Renamed support->viewpager, removed old deprecated code

Fixes #582

.travis.yml

@@ -3,8 +3,8 @@ language: android
 android:
   components:
     - tools
-    - build-tools-25.0.0
-    - android-25
+    - build-tools-28.0.3
+    - android-28
     - extra-android-m2repository
   licenses:
     - '.+'
@@ -31,5 +31,5 @@ sudo: false
 
 env:
   global:
-    - secure: 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
-    - secure: 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
+    - secure: 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
+    - secure: 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

CONTRIBUTING.md

@@ -0,0 +1,70 @@
+# Community Contribution Guidelines
+
+As the creators and maintainers of this project, we want to ensure that the project lives and continues to grow. Not blocked by any singular person's computer time. One of the simplest ways of doing this is by encouraging a larger set of shallow contributors. Through this, we hope to mitigate the problems of a project that needs updates, but there is no-one who has the power to do so.
+
+#### Development Process
+
+We maintain two permanent, protected branches: `master` and `development`.
+
+`master` is for the current release. It has already been distributed to jcenter and can't be modified at this point (except for docs that may be incorrect for the current release!).
+
+`development` is where we stage work for the *next* release. Pull requests should be directed to this branch.
+
+When working on a new feature or fix that may span multiple commits, please do so in a feature branch (ex: `feature/my_cool_thing`). Please clean up these feature branches once merged into `development`.
+
+When a new version is ready to be released, please create a pull request to merge `development` into `master`, named something like "Release 10.0". Then we can have some final discussion before we merge it into `master` and push the release out to the public.
+
+Since `development` is a *shared* branch, it is important not to ever rebase this branch onto `master`. If a bug fix is applied to `master` it can be merged into `development` using good old simple `git checkout development && git merge master`. Yes this will clutter the history a little bit, but it also provides important context to know how/when a patch was applied. Merge commits can be considered necessary historical data, not warts on an idealized history graph.
+
+#### Testing
+
+To run tests locally, just run `./gradlew test`. Tests should always be run before pushing anything to the repo.
+
+#### Ownership
+
+If you get a merged pull-request of substance (ie not just a typo fix), then you are eligible for push access to this repo. Simply request access via a new GitHub issue.
+
+Offhand, it is easy to imagine that this would make code quality suffer, but in reality it offers fresh perspectives to the codebase and encourages ownership from people who are depending on the project. If you are building a project that relies on this codebase, then you probably have the skills to improve it and offer valuable feedback. At the end of the day, there isn't too much risk in this, as the `master` branch is still locked, and jcenter access is still being restricted.
+
+Everyone comes in with their own perspective on what a project could/should look like, and encouraging discussion can help expose good ideas sooner.
+
+#### Why do we give out push access?
+
+It can be overwhelming to be offered the chance to wipe the source code for a project. Do not worry, we do not let you push to master. All code is peer-reviewed, and we have the convention that someone other than the submitter should merge non-trivial pull requests.
+
+As a contributor, you can merge other people's pull requests, or other contributors can merge yours. You will not be assigned a pull request, but you are welcome to jump in and take a code review on topics that interest you.
+
+This project is not continuously deployed, there is space for debate after review too. Offering everyone the chance to revert, or make an amending pull request. If it feels right, merge.
+
+#### How can we help you get comfortable contributing?
+
+It is normal for a first pull request to be a potential fix for a problem, and moving on from there to helping the project's direction can be difficult. We will try to help contributors cross that barrier by offering good first step issues. These issues can be fixed without feeling like you are stepping on toes. Ideally, these are non-critical issues that are well defined. They will be purposely avoided by mature contributors to the project, to make space for others.
+
+We aim to keep all project discussion inside GitHub issues. This is to make sure valuable discussion is accessible via search. If you have questions about how to use the library, or how the project is running - GitHub issues are the goto tool for this project.
+
+#### Our expectations on you as a contributor
+
+To quote [@alloy](https://github.com/alloy) from [this issue](https://github.com/Moya/Moya/issues/135):
+
+> Do not ever feel bad for not contributing to open source.
+
+We want contributors to provide ideas, keep the ship shipping and to take some of the load from others. It is non-obligatory; we’re here to get things done in an enjoyable way. :trophy:
+
+The fact that you will have push access will allow you to:
+
+- Avoid having to fork the project if you want to submit other pull requests, as you will be able to create branches directly on the project.
+- Help triage issues and merge pull requests.
+- Pick up the project if other maintainers move their focus elsewhere.
+
+It is up to you to use those superpowers or not though 😉
+
+If someone submits a pull request that is not perfect, and you are reviewing, it is better to think about the PR's motivation rather than the specific implementation. Having braces on the wrong line should not be a blocker. Though we do want to keep test coverage high, we will work with you to figure that out together.
+
+#### What about if you have problems that cannot be discussed in a public issue?
+
+[Eric Kuck](https://github.com/erickuck) has a contactable email on his GitHub profile, and is happy to talk about any problems.
+
+#### This is a different way to handle open source! Where did it come from?
+
+The original source of this document can be found at [https://github.com/moya/contributors](https://github.com/moya/contributors).
+

README.md

@@ -1,4 +1,4 @@
-[![Travis Build](https://travis-ci.org/bluelinelabs/Conductor.svg)](https://travis-ci.org/bluelinelabs/Conductor) [![Android Arsenal](https://img.shields.io/badge/Android%20Arsenal-Conductor-brightgreen.svg?style=flat)](http://android-arsenal.com/details/1/3361) [![Javadocs](http://javadoc.io/badge/com.bluelinelabs/conductor.svg)](http://javadoc.io/doc/com.bluelinelabs/conductor)
+[![Travis Build](https://travis-ci.com/bluelinelabs/Conductor.svg)](https://travis-ci.com/bluelinelabs/Conductor) [![Android Arsenal](https://img.shields.io/badge/Android%20Arsenal-Conductor-brightgreen.svg?style=flat)](http://android-arsenal.com/details/1/3361) [![Javadocs](http://javadoc.io/badge/com.bluelinelabs/conductor.svg)](http://javadoc.io/doc/com.bluelinelabs/conductor)
 
 # Conductor
 
@@ -20,36 +20,36 @@ Conductor is architecture-agnostic and does not try to force any design decision
 ## Installation
 
 ```gradle
-compile 'com.bluelinelabs:conductor:2.1.3'
+implementation 'com.bluelinelabs:conductor:3.0.0-rc3'
 
-// If you want the components that go along with
-// Android's support libraries (currently just a PagerAdapter):
-compile 'com.bluelinelabs:conductor-support:2.1.3'
+// If you want AndroidX Transition change handlers:
+implementation 'com.bluelinelabs:conductor-androidx-transition:3.0.0-rc3'
+
+// If you want a PagerAdapter for ViewPager:
+implementation 'com.bluelinelabs:conductor-viewpager:3.0.0-rc3'
 
 // If you want RxJava lifecycle support:
-compile 'com.bluelinelabs:conductor-rxlifecycle:2.1.3'
+implementation 'com.bluelinelabs:conductor-rxlifecycle:3.0.0-rc3'
 
 // If you want RxJava2 lifecycle support:
-compile 'com.bluelinelabs:conductor-rxlifecycle2:2.1.3'
+implementation 'com.bluelinelabs:conductor-rxlifecycle2:3.0.0-rc3'
+
+// If you want RxJava2 Autodispose support:
+implementation 'com.bluelinelabs:conductor-autodispose:3.0.0-rc3'
+
+// If you want Controllers that are Lifecycle-aware (architecture components):
+implementation 'com.bluelinelabs:conductor-archlifecycle:3.0.0-rc3'
 ```
 
-SNAPSHOT:
+**SNAPSHOT**
 
-```gradle
-compile 'com.bluelinelabs:conductor:2.1.4-SNAPSHOT'
-compile 'com.bluelinelabs:conductor-support:2.1.4-SNAPSHOT'
-compile 'com.bluelinelabs:conductor-rxlifecycle:2.1.4-SNAPSHOT'
-compile 'com.bluelinelabs:conductor-rxlifecycle2:2.1.4-SNAPSHOT'
-```
-
-You also have to add the url to the snapshot repository:
+Just use `3.0.1-SNAPSHOT` as your version number in any of the dependencies above and add the url to the snapshot repository:
 
 ```gradle
 allprojects {
   repositories {
-    ...
-
     maven { url "https://oss.sonatype.org/content/repositories/snapshots/" }
+  }
 }
 ```
 
@@ -60,7 +60,7 @@ allprojects {
 __Controller__ | The Controller is the View wrapper that will give you all of your lifecycle management features. Think of it as a lighter-weight and more predictable Fragment alternative with an easier to manage lifecycle.
 __Router__ | A Router implements navigation and backstack handling for Controllers. Router objects are attached to Activity/containing ViewGroup pairs. Routers do not directly render or push Views to the container ViewGroup, but instead defer this responsibility to the ControllerChangeHandler specified in a given transaction.
 __ControllerChangeHandler__ | ControllerChangeHandlers are responsible for swapping the View for one Controller to the View of another. They can be useful for performing animations and transitions between Controllers. Several default ControllerChangeHandlers are included.
-__ControllerTransaction__ | Transactions are used to define data about adding Controllers. RouterControllerTransactions are used to push a Controller to a Router with specified ControllerChangeHandlers, while ChildControllerTransactions are used to add child Controllers.
+__RouterTransaction__ | Transactions are used to define data about adding Controllers. RouterTransactions are used to push a Controller to a Router with specified ControllerChangeHandlers, while ChildControllerTransactions are used to add child Controllers.
 
 ## Getting Started
 
@@ -77,7 +77,7 @@ public class MainActivity extends Activity {
 
         setContentView(R.layout.activity_main);
 
-        ViewGroup container = (ViewGroup)findViewById(R.id.controller_container);
+        ViewGroup container = (ViewGroup) findViewById(R.id.controller_container);
 
         router = Conductor.attachRouter(this, container, savedInstanceState);
         if (!router.hasRootController()) {
@@ -103,7 +103,7 @@ public class HomeController extends Controller {
     @Override
     protected View onCreateView(@NonNull LayoutInflater inflater, @NonNull ViewGroup container) {
         View view = inflater.inflate(R.layout.controller_home, container, false);
-        ((TextView)view.findViewById(R.id.tv_title)).setText("Hello World");
+        ((TextView) view.findViewById(R.id.tv_title)).setText("Hello World");
         return view;
     }
 
@@ -132,7 +132,15 @@ The lifecycle of a Controller is significantly simpler to understand than that o
 `getChildRouter` can be called on a `Controller` in order to get a nested `Router` into which child `Controller`s can be pushed. This enables creating advanced layouts, such as Master/Detail.
 
 ### RxJava Lifecycle
-If the RxLifecycle dependency has been added, there is an `RxController` available that can be used along with the standard [RxLifecycle library](https://github.com/trello/RxLifecycle). There is also a `ControllerLifecycleProvider` available if you do not wish to use this subclass.
+If the AutoDispose dependency has been added, there is a `ControllerScopeProvider` available that can be used along with the standard [AutoDispose library](https://github.com/uber/AutoDispose).
+
+## Community Projects
+The community has provided several helpful modules to make developing apps with Conductor even easier. Here's a collection of helpful libraries:
+
+* [ConductorGlide](https://github.com/MkhytarMkhoian/ConductorGlide) - Adds Glide lifecycle support to Controllers
+* [ConductorDialog](https://github.com/MkhytarMkhoian/ConductorDialog) - Adds a helpful DialogController (a Conductor version of DialogFragment)
+* [Mosby-Conductor](https://github.com/sockeqwe/mosby-conductor) - A plugin to integrate Mosby, an MVP/MVI library
+
 
 ## License
 ```

build.gradle

@@ -1,16 +1,18 @@
 buildscript {
     repositories {
         jcenter()
+        google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.3.0'
+        classpath 'com.android.tools.build:gradle:3.5.2'
     }
 }
 
 allprojects {
     repositories {
-        jcenter()
         mavenCentral()
+        maven { url 'https://maven.google.com' }
+        jcenter()
     }
 }
 

conductor-lint/build.gradle

@@ -8,11 +8,11 @@ configurations {
 }
 
 dependencies {
-    compile rootProject.ext.lintapi
-    compile rootProject.ext.lintchecks
+    implementation rootProject.ext.lintapi
+    implementation rootProject.ext.lintchecks
 
-    testCompile rootProject.ext.lint
-    testCompile rootProject.ext.lintTests
+    testImplementation rootProject.ext.lint
+    testImplementation rootProject.ext.lintTests
 
     lintChecks files(jar)
 }

conductor-lint/src/main/java/com/bluelinelabs/conductor/lint/ControllerChangeHandlerIssueDetector.java

@@ -1,6 +1,7 @@
 package com.bluelinelabs.conductor.lint;
 
 import com.android.tools.lint.client.api.JavaEvaluator;
+import com.android.tools.lint.client.api.UElementHandler;
 import com.android.tools.lint.detector.api.Category;
 import com.android.tools.lint.detector.api.Detector;
 import com.android.tools.lint.detector.api.Implementation;
@@ -8,13 +9,16 @@ import com.android.tools.lint.detector.api.Issue;
 import com.android.tools.lint.detector.api.JavaContext;
 import com.android.tools.lint.detector.api.Scope;
 import com.android.tools.lint.detector.api.Severity;
-import com.intellij.psi.PsiClass;
-import com.intellij.psi.PsiMethod;
+
+import org.jetbrains.uast.UClass;
+import org.jetbrains.uast.UElement;
+import org.jetbrains.uast.UMethod;
+import org.jetbrains.uast.UTypeReferenceExpression;
 
 import java.util.Collections;
 import java.util.List;
 
-public final class ControllerChangeHandlerIssueDetector extends Detector implements Detector.JavaPsiScanner {
+public final class ControllerChangeHandlerIssueDetector extends Detector implements Detector.UastScanner {
 
     public static final Issue ISSUE =
             Issue.create("ValidControllerChangeHandler", "ControllerChangeHandler not instantiatable",
@@ -23,47 +27,67 @@ public final class ControllerChangeHandlerIssueDetector extends Detector impleme
                     Category.CORRECTNESS, 6, Severity.FATAL,
                     new Implementation(ControllerChangeHandlerIssueDetector.class, Scope.JAVA_FILE_SCOPE));
 
-    public ControllerChangeHandlerIssueDetector() { }
+    private static final String CLASS_NAME = "com.bluelinelabs.conductor.ControllerChangeHandler";
 
     @Override
-    public List<String> applicableSuperClasses() {
-        return Collections.singletonList("com.bluelinelabs.conductor.ControllerChangeHandler");
+    public List<Class<? extends UElement>> getApplicableUastTypes() {
+        return Collections.<Class<? extends UElement>>singletonList(UClass.class);
     }
 
     @Override
-    public void checkClass(JavaContext context, PsiClass declaration) {
+    public UElementHandler createUastHandler(final JavaContext context) {
         final JavaEvaluator evaluator = context.getEvaluator();
-        if (evaluator.isAbstract(declaration)) {
-            return;
-        }
 
-        if (!evaluator.isPublic(declaration)) {
-            String message = String.format("This ControllerChangeHandler class should be public (%1$s)", declaration.getQualifiedName());
-            context.report(ISSUE, declaration, context.getLocation(declaration), message);
-            return;
-        }
+        return new UElementHandler() {
 
-        if (declaration.getContainingClass() != null && !evaluator.isStatic(declaration)) {
-            String message = String.format("This ControllerChangeHandler inner class should be static (%1$s)", declaration.getQualifiedName());
-            context.report(ISSUE, declaration, context.getLocation(declaration), message);
-            return;
-        }
+            @Override
+            public void visitClass(UClass node) {
+                if (evaluator.isAbstract(node)) {
+                    return;
+                }
 
-        boolean hasDefaultConstructor = false;
-        PsiMethod[] constructors = declaration.getConstructors();
-        for (PsiMethod constructor : constructors) {
-            if (evaluator.isPublic(constructor)) {
-                if (constructor.getParameterList().getParametersCount() == 0) {
-                    hasDefaultConstructor = true;
-                    break;
+                boolean hasSuperType = false;
+                for (UTypeReferenceExpression superType : node.getUastSuperTypes()) {
+                    if (CLASS_NAME.equals(superType.asRenderString())) {
+                        hasSuperType = true;
+                        break;
+                    }
+                }
+                if (!hasSuperType) {
+                    return;
+                }
+
+                if (!evaluator.isPublic(node)) {
+                    String message = String.format("This ControllerChangeHandler class should be public (%1$s)", node.getQualifiedName());
+                    context.report(ISSUE, node, context.getLocation((UElement) node), message);
+                    return;
+                }
+
+                if (node.getContainingClass() != null && !evaluator.isStatic(node)) {
+                    String message = String.format("This ControllerChangeHandler inner class should be static (%1$s)", node.getQualifiedName());
+                    context.report(ISSUE, node, context.getLocation((UElement) node), message);
+                    return;
+                }
+
+                boolean hasConstructor = false;
+                boolean hasDefaultConstructor = false;
+                for (UMethod method : node.getMethods()) {
+                    if (method.isConstructor()) {
+                        hasConstructor = true;
+                        if (evaluator.isPublic(method) && method.getUastParameters().size() == 0) {
+                            hasDefaultConstructor = true;
+                            break;
+                        }
+                    }
+                }
+
+                if (hasConstructor && !hasDefaultConstructor) {
+                    String message = String.format(
+                            "This ControllerChangeHandler needs to have a public default constructor (`%1$s`)", node.getQualifiedName());
+                    context.report(ISSUE, node, context.getLocation((UElement) node), message);
                 }
             }
-        }
-
-        if (constructors.length > 0 && !hasDefaultConstructor) {
-            String message = String.format(
-                    "This ControllerChangeHandler needs to have a public default constructor (`%1$s`)", declaration.getQualifiedName());
-            context.report(ISSUE, declaration, context.getLocation(declaration), message);
-        }
+        };
     }
-}
+
+}

conductor-lint/src/main/java/com/bluelinelabs/conductor/lint/ControllerIssueDetector.java

@@ -2,6 +2,7 @@ package com.bluelinelabs.conductor.lint;
 
 import com.android.SdkConstants;
 import com.android.tools.lint.client.api.JavaEvaluator;
+import com.android.tools.lint.client.api.UElementHandler;
 import com.android.tools.lint.detector.api.Category;
 import com.android.tools.lint.detector.api.Detector;
 import com.android.tools.lint.detector.api.Implementation;
@@ -9,14 +10,17 @@ import com.android.tools.lint.detector.api.Issue;
 import com.android.tools.lint.detector.api.JavaContext;
 import com.android.tools.lint.detector.api.Scope;
 import com.android.tools.lint.detector.api.Severity;
-import com.intellij.psi.PsiClass;
-import com.intellij.psi.PsiMethod;
-import com.intellij.psi.PsiParameter;
+
+import org.jetbrains.uast.UClass;
+import org.jetbrains.uast.UElement;
+import org.jetbrains.uast.UMethod;
+import org.jetbrains.uast.UParameter;
+import org.jetbrains.uast.UTypeReferenceExpression;
 
 import java.util.Collections;
 import java.util.List;
 
-public final class ControllerIssueDetector extends Detector implements Detector.JavaPsiScanner {
+public final class ControllerIssueDetector extends Detector implements Detector.UastScanner {
 
     public static final Issue ISSUE =
             Issue.create("ValidController", "Controller not instantiatable",
@@ -25,58 +29,76 @@ public final class ControllerIssueDetector extends Detector implements Detector.
                             + " case of the process being killed.", Category.CORRECTNESS, 6, Severity.FATAL,
                     new Implementation(ControllerIssueDetector.class, Scope.JAVA_FILE_SCOPE));
 
-    public ControllerIssueDetector() { }
+    private static final String CLASS_NAME = "com.bluelinelabs.conductor.Controller";
 
     @Override
-    public List<String> applicableSuperClasses() {
-        return Collections.singletonList("com.bluelinelabs.conductor.Controller");
+    public List<Class<? extends UElement>> getApplicableUastTypes() {
+        return Collections.<Class<? extends UElement>>singletonList(UClass.class);
     }
 
     @Override
-    public void checkClass(JavaContext context, PsiClass declaration) {
+    public UElementHandler createUastHandler(final JavaContext context) {
         final JavaEvaluator evaluator = context.getEvaluator();
-        if (evaluator.isAbstract(declaration)) {
-            return;
-        }
 
-        if (!evaluator.isPublic(declaration)) {
-            String message = String.format("This Controller class should be public (%1$s)", declaration.getQualifiedName());
-            context.report(ISSUE, declaration, context.getLocation(declaration), message);
-            return;
-        }
+        return new UElementHandler() {
+            @Override
+            public void visitClass(UClass node) {
+                if (evaluator.isAbstract(node)) {
+                    return;
+                }
 
-        if (declaration.getContainingClass() != null && !evaluator.isStatic(declaration)) {
-            String message = String.format("This Controller inner class should be static (%1$s)", declaration.getQualifiedName());
-            context.report(ISSUE, declaration, context.getLocation(declaration), message);
-            return;
-        }
+                boolean hasSuperType = false;
+                for (UTypeReferenceExpression superType : node.getUastSuperTypes()) {
+                    if (CLASS_NAME.equals(superType.asRenderString())) {
+                        hasSuperType = true;
+                        break;
+                    }
+                }
+                if (!hasSuperType) {
+                    return;
+                }
 
+                if (!evaluator.isPublic(node)) {
+                    String message = String.format("This Controller class should be public (%1$s)", node.getQualifiedName());
+                    context.report(ISSUE, node, context.getLocation((UElement) node), message);
+                    return;
+                }
 
-        boolean hasDefaultConstructor = false;
-        boolean hasBundleConstructor = false;
-        PsiMethod[] constructors = declaration.getConstructors();
-        for (PsiMethod constructor : constructors) {
-            if (evaluator.isPublic(constructor)) {
-                PsiParameter[] parameters = constructor.getParameterList().getParameters();
+                if (node.getContainingClass() != null && !evaluator.isStatic(node)) {
+                    String message = String.format("This Controller inner class should be static (%1$s)", node.getQualifiedName());
+                    context.report(ISSUE, node, context.getLocation((UElement) node), message);
+                    return;
+                }
 
-                if (parameters.length == 0) {
-                    hasDefaultConstructor = true;
-                    break;
-                } else if (parameters.length == 1 &&
-                        parameters[0].getType().equalsToText(SdkConstants.CLASS_BUNDLE) ||
-                        parameters[0].getType().equalsToText("Bundle")) {
-                    hasBundleConstructor = true;
-                    break;
+                boolean hasConstructor = false;
+                boolean hasDefaultConstructor = false;
+                boolean hasBundleConstructor = false;
+                for (UMethod method : node.getMethods()) {
+                    if (method.isConstructor()) {
+                        hasConstructor = true;
+                        if (evaluator.isPublic(method)) {
+                            List<UParameter> parameters = method.getUastParameters();
+                            if (parameters.size() == 0) {
+                                hasDefaultConstructor = true;
+                                break;
+                            } else if (parameters.size() == 1 &&
+                                    (parameters.get(0).getType().equalsToText(SdkConstants.CLASS_BUNDLE)) ||
+                                    parameters.get(0).getType().equalsToText("Bundle")) {
+                                hasBundleConstructor = true;
+                            }
+                        }
+                    }
+                }
+
+                if (hasConstructor && !hasDefaultConstructor && !hasBundleConstructor) {
+                    String message = String.format(
+                            "This Controller needs to have either a public default constructor or a" +
+                                    " public single-argument constructor that takes a Bundle. (`%1$s`)",
+                            node.getQualifiedName());
+                    context.report(ISSUE, node, context.getLocation((UElement) node), message);
                 }
             }
-        }
-
-        if (constructors.length > 0 && !hasDefaultConstructor && !hasBundleConstructor) {
-            String message = String.format(
-                    "This Controller needs to have either a public default constructor or a" +
-                            " public single-argument constructor that takes a Bundle. (`%1$s`)",
-                    declaration.getQualifiedName());
-            context.report(ISSUE, declaration, context.getLocation(declaration), message);
-        }
+        };
     }
-}
+    
+}

conductor-lint/src/main/java/com/bluelinelabs/conductor/lint/IssueRegistry.java

@@ -5,10 +5,19 @@ import com.android.tools.lint.detector.api.Issue;
 import java.util.Arrays;
 import java.util.List;
 
+import static com.android.tools.lint.detector.api.ApiKt.CURRENT_API;
+
 public final class IssueRegistry extends com.android.tools.lint.client.api.IssueRegistry {
-    @Override public List<Issue> getIssues() {
+
+    @Override
+    public List<Issue> getIssues() {
         return Arrays.asList(
                 ControllerIssueDetector.ISSUE,
                 ControllerChangeHandlerIssueDetector.ISSUE);
     }
-}
+
+    @Override
+    public int getApi() {
+        return CURRENT_API;
+    }
+}

conductor-lint/src/test/java/com/bluelinelabs/conductor/lint/ControllerChangeHandlerDetectorTest.java

@@ -1,19 +1,13 @@
 package com.bluelinelabs.conductor.lint;
 
-import com.android.tools.lint.checks.infrastructure.LintDetectorTest;
-import com.android.tools.lint.detector.api.Detector;
-import com.android.tools.lint.detector.api.Issue;
-
 import org.intellij.lang.annotations.Language;
+import org.junit.Test;
 
-import java.util.Collections;
-import java.util.List;
+import static com.android.tools.lint.checks.infrastructure.TestFiles.java;
+import static com.android.tools.lint.checks.infrastructure.TestLintTask.lint;
 
-import static com.google.common.truth.Truth.assertThat;
+public class ControllerChangeHandlerDetectorTest {
 
-public class ControllerChangeHandlerDetectorTest extends LintDetectorTest {
-
-    private static final String NO_WARNINGS = "No warnings.";
     private static final String CONSTRUCTOR =
             "src/test/SampleHandler.java:2: Error: This ControllerChangeHandler needs to have a public default constructor (test.SampleHandler) [ValidControllerChangeHandler]\n"
             + "public class SampleHandler extends com.bluelinelabs.conductor.ControllerChangeHandler {\n"
@@ -25,72 +19,94 @@ public class ControllerChangeHandlerDetectorTest extends LintDetectorTest {
                     + "^\n"
                     + "1 errors, 0 warnings\n";
 
-    public void testWithNoConstructor() throws Exception {
+    @Test
+    public void testWithNoConstructor() {
         @Language("JAVA") String source = ""
                 + "package test;\n"
                 + "public class SampleHandler extends com.bluelinelabs.conductor.ControllerChangeHandler {\n"
                 + "}";
-        assertThat(lintProject(java(source))).isEqualTo(NO_WARNINGS);
+
+        lint()
+                .files(java(source))
+                .issues(ControllerIssueDetector.ISSUE, ControllerChangeHandlerIssueDetector.ISSUE)
+                .run()
+                .expectClean();
     }
 
-    public void testWithEmptyConstructor() throws Exception {
+    @Test
+    public void testWithEmptyConstructor() {
         @Language("JAVA") String source = ""
                 + "package test;\n"
                 + "public class SampleHandler extends com.bluelinelabs.conductor.ControllerChangeHandler {\n"
                 + "    public SampleHandler() { }\n"
                 + "}";
-        assertThat(lintProject(java(source))).isEqualTo(NO_WARNINGS);
+
+        lint()
+                .files(java(source))
+                .issues(ControllerIssueDetector.ISSUE, ControllerChangeHandlerIssueDetector.ISSUE)
+                .run()
+                .expectClean();
     }
 
-    public void testWithInvalidConstructor() throws Exception {
+    @Test
+    public void testWithInvalidConstructor() {
         @Language("JAVA") String source = ""
                 + "package test;\n"
                 + "public class SampleHandler extends com.bluelinelabs.conductor.ControllerChangeHandler {\n"
                 + "    public SampleHandler(int number) { }\n"
                 + "}";
-        assertThat(lintProject(java(source))).isEqualTo(CONSTRUCTOR);
+
+        lint()
+                .files(java(source))
+                .issues(ControllerIssueDetector.ISSUE, ControllerChangeHandlerIssueDetector.ISSUE)
+                .run()
+                .expect(CONSTRUCTOR);
     }
 
-    public void testWithEmptyAndInvalidConstructor() throws Exception {
+    @Test
+    public void testWithEmptyAndInvalidConstructor() {
         @Language("JAVA") String source = ""
                 + "package test;\n"
                 + "public class SampleHandler extends com.bluelinelabs.conductor.ControllerChangeHandler {\n"
                 + "    public SampleHandler() { }\n"
                 + "    public SampleHandler(int number) { }\n"
                 + "}";
-        assertThat(lintProject(java(source))).isEqualTo(NO_WARNINGS);
+
+        lint()
+                .files(java(source))
+                .issues(ControllerIssueDetector.ISSUE, ControllerChangeHandlerIssueDetector.ISSUE)
+                .run()
+                .expectClean();
     }
 
-    public void testWithPrivateConstructor() throws Exception {
+    @Test
+    public void testWithPrivateConstructor() {
         @Language("JAVA") String source = ""
                 + "package test;\n"
                 + "public class SampleHandler extends com.bluelinelabs.conductor.ControllerChangeHandler {\n"
                 + "    private SampleHandler() { }\n"
                 + "}";
-        assertThat(lintProject(java(source))).isEqualTo(CONSTRUCTOR);
+
+        lint()
+                .files(java(source))
+                .issues(ControllerIssueDetector.ISSUE, ControllerChangeHandlerIssueDetector.ISSUE)
+                .run()
+                .expect(CONSTRUCTOR);
     }
 
-    public void testWithPrivateClass() throws Exception {
+    @Test
+    public void testWithPrivateClass() {
         @Language("JAVA") String source = ""
                 + "package test;\n"
                 + "private class SampleHandler extends com.bluelinelabs.conductor.ControllerChangeHandler {\n"
                 + "    public SampleHandler() { }\n"
                 + "}";
-        assertThat(lintProject(java(source))).isEqualTo(PRIVATE_CLASS_ERROR);
+
+        lint()
+                .files(java(source))
+                .issues(ControllerIssueDetector.ISSUE, ControllerChangeHandlerIssueDetector.ISSUE)
+                .run()
+                .expect(PRIVATE_CLASS_ERROR);
     }
 
-    @Override
-    protected Detector getDetector() {
-        return new ControllerChangeHandlerIssueDetector();
-    }
-
-    @Override
-    protected List<Issue> getIssues() {
-        return Collections.singletonList(ControllerChangeHandlerIssueDetector.ISSUE);
-    }
-
-    @Override
-    protected boolean allowCompilationErrors() {
-        return true;
-    }
 }

conductor-lint/src/test/java/com/bluelinelabs/conductor/lint/ControllerDetectorTest.java

@@ -1,19 +1,13 @@
 package com.bluelinelabs.conductor.lint;
 
-import com.android.tools.lint.checks.infrastructure.LintDetectorTest;
-import com.android.tools.lint.detector.api.Detector;
-import com.android.tools.lint.detector.api.Issue;
-
 import org.intellij.lang.annotations.Language;
+import org.junit.Test;
 
-import java.util.Collections;
-import java.util.List;
+import static com.android.tools.lint.checks.infrastructure.TestFiles.java;
+import static com.android.tools.lint.checks.infrastructure.TestLintTask.lint;
 
-import static com.google.common.truth.Truth.assertThat;
+public class ControllerDetectorTest {
 
-public class ControllerDetectorTest extends LintDetectorTest {
-
-    private static final String NO_WARNINGS = "No warnings.";
     private static final String CONSTRUCTOR_ERROR =
             "src/test/SampleController.java:2: Error: This Controller needs to have either a public default constructor or a public single-argument constructor that takes a Bundle. (test.SampleController) [ValidController]\n"
             + "public class SampleController extends com.bluelinelabs.conductor.Controller {\n"
@@ -25,72 +19,94 @@ public class ControllerDetectorTest extends LintDetectorTest {
                     + "^\n"
                     + "1 errors, 0 warnings\n";
 
-    public void testWithNoConstructor() throws Exception {
+    @Test
+    public void testWithNoConstructor() {
         @Language("JAVA") String source = ""
                 + "package test;\n"
                 + "public class SampleController extends com.bluelinelabs.conductor.Controller {\n"
                 + "}";
-        assertThat(lintProject(java(source))).isEqualTo(NO_WARNINGS);
+
+        lint()
+                .files(java(source))
+                .issues(ControllerIssueDetector.ISSUE, ControllerChangeHandlerIssueDetector.ISSUE)
+                .run()
+                .expectClean();
     }
 
-    public void testWithEmptyConstructor() throws Exception {
+    @Test
+    public void testWithEmptyConstructor() {
         @Language("JAVA") String source = ""
                 + "package test;\n"
                 + "public class SampleController extends com.bluelinelabs.conductor.Controller {\n"
                 + "    public SampleController() { }\n"
                 + "}";
-        assertThat(lintProject(java(source))).isEqualTo(NO_WARNINGS);
+
+        lint()
+                .files(java(source))
+                .issues(ControllerIssueDetector.ISSUE, ControllerChangeHandlerIssueDetector.ISSUE)
+                .run()
+                .expectClean();
     }
 
-    public void testWithInvalidConstructor() throws Exception {
+    @Test
+    public void testWithInvalidConstructor() {
         @Language("JAVA") String source = ""
                 + "package test;\n"
                 + "public class SampleController extends com.bluelinelabs.conductor.Controller {\n"
                 + "    public SampleController(int number) { }\n"
                 + "}";
-        assertThat(lintProject(java(source))).isEqualTo(CONSTRUCTOR_ERROR);
+
+        lint()
+                .files(java(source))
+                .issues(ControllerIssueDetector.ISSUE, ControllerChangeHandlerIssueDetector.ISSUE)
+                .run()
+                .expect(CONSTRUCTOR_ERROR);
     }
 
-    public void testWithEmptyAndInvalidConstructor() throws Exception {
+    @Test
+    public void testWithEmptyAndInvalidConstructor() {
         @Language("JAVA") String source = ""
                 + "package test;\n"
                 + "public class SampleController extends com.bluelinelabs.conductor.Controller {\n"
                 + "    public SampleController() { }\n"
                 + "    public SampleController(int number) { }\n"
                 + "}";
-        assertThat(lintProject(java(source))).isEqualTo(NO_WARNINGS);
+
+        lint()
+                .files(java(source))
+                .issues(ControllerIssueDetector.ISSUE, ControllerChangeHandlerIssueDetector.ISSUE)
+                .run()
+                .expectClean();
     }
 
-    public void testWithPrivateConstructor() throws Exception {
+    @Test
+    public void testWithPrivateConstructor() {
         @Language("JAVA") String source = ""
                 + "package test;\n"
                 + "public class SampleController extends com.bluelinelabs.conductor.Controller {\n"
                 + "    private SampleController() { }\n"
                 + "}";
-        assertThat(lintProject(java(source))).isEqualTo(CONSTRUCTOR_ERROR);
+
+        lint()
+                .files(java(source))
+                .issues(ControllerIssueDetector.ISSUE, ControllerChangeHandlerIssueDetector.ISSUE)
+                .run()
+                .expect(CONSTRUCTOR_ERROR);
     }
 
-    public void testWithPrivateClass() throws Exception {
+    @Test
+    public void testWithPrivateClass() {
         @Language("JAVA") String source = ""
                 + "package test;\n"
                 + "private class SampleController extends com.bluelinelabs.conductor.Controller {\n"
                 + "    public SampleController() { }\n"
                 + "}";
-        assertThat(lintProject(java(source))).isEqualTo(CLASS_ERROR);
+
+        lint()
+                .files(java(source))
+                .issues(ControllerIssueDetector.ISSUE, ControllerChangeHandlerIssueDetector.ISSUE)
+                .run()
+                .expect(CLASS_ERROR);
     }
 
-    @Override
-    protected Detector getDetector() {
-        return new ControllerIssueDetector();
-    }
-
-    @Override
-    protected List<Issue> getIssues() {
-        return Collections.singletonList(ControllerIssueDetector.ISSUE);
-    }
-
-    @Override
-    protected boolean allowCompilationErrors() {
-        return true;
-    }
 }

conductor-modules/androidx-transition/build.gradle

@@ -0,0 +1,35 @@
+buildscript {
+    repositories {
+        jcenter()
+    }
+}
+
+apply plugin: 'com.android.library'
+
+android {
+    compileSdkVersion rootProject.ext.compileSdkVersion
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_7
+        targetCompatibility JavaVersion.VERSION_1_7
+    }
+
+    defaultConfig {
+        minSdkVersion rootProject.ext.minSdkVersion
+        targetSdkVersion rootProject.ext.targetSdkVersion
+        versionCode Integer.parseInt(project.VERSION_CODE)
+        versionName project.VERSION_NAME
+    }
+}
+
+dependencies {
+    implementation rootProject.ext.androidxAppCompat
+    implementation rootProject.ext.androidxCollection
+    api rootProject.ext.androidxTransition
+    implementation project(':conductor')
+}
+
+ext.artifactId = 'conductor-androidx-transition'
+
+apply from: rootProject.file('dependencies.gradle')
+apply from: rootProject.file('gradle-mvn-push.gradle')

conductor-modules/androidx-transition/gradle.properties

@@ -0,0 +1,3 @@
+POM_NAME=Conductor AndroidX Transition Extensions
+POM_ARTIFACT_ID=conductor-androidx-transition
+POM_PACKAGING=aar

conductor-modules/androidx-transition/src/main/AndroidManifest.xml

@@ -0,0 +1,3 @@
+<manifest package="com.bluelinelabs.conductor.androidxtransition">
+    <application />
+</manifest>

conductor-modules/androidx-transition/src/main/java/com/bluelinelabs/conductor/changehandler/androidxtransition/SharedElementTransitionChangeHandler.java

@@ -0,0 +1,653 @@
+package com.bluelinelabs.conductor.changehandler.androidxtransition;
+
+import android.graphics.Rect;
+import android.view.View;
+import android.view.ViewGroup;
+import android.view.ViewTreeObserver;
+import android.view.ViewTreeObserver.OnPreDrawListener;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.collection.ArrayMap;
+import androidx.core.app.SharedElementCallback;
+import androidx.core.view.ViewCompat;
+import androidx.core.view.ViewGroupCompat;
+import androidx.transition.Transition;
+import androidx.transition.TransitionSet;
+
+import com.bluelinelabs.conductor.Controller;
+import com.bluelinelabs.conductor.ControllerChangeHandler;
+import com.bluelinelabs.conductor.internal.TransitionUtils;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A TransitionChangeHandler that facilitates using different Transitions for the entering view, the exiting view,
+ * and shared elements between the two.
+ */
+// Much of this class is based on FragmentTransition.java and FragmentTransitionCompat21.java from the Android support library
+public abstract class SharedElementTransitionChangeHandler extends TransitionChangeHandler {
+
+    // A map of from -> to names. Generally these will be the same.
+    @NonNull  final ArrayMap<String, String> sharedElementNames = new ArrayMap<>();
+
+    @NonNull  final List<String> waitForTransitionNames = new ArrayList<>();
+    @NonNull  final List<ViewParentPair> removedViews = new ArrayList<>();
+
+    @Nullable Transition exitTransition;
+    @Nullable Transition enterTransition;
+    @Nullable Transition sharedElementTransition;
+    @Nullable private SharedElementCallback exitTransitionCallback;
+    @Nullable private SharedElementCallback enterTransitionCallback;
+
+    @NonNull
+    @Override
+    protected final Transition getTransition(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush) {
+        exitTransition = getExitTransition(container, from, to, isPush);
+        enterTransition = getEnterTransition(container, from, to, isPush);
+        sharedElementTransition = getSharedElementTransition(container, from, to, isPush);
+        exitTransitionCallback = getExitTransitionCallback(container, from, to, isPush);
+        enterTransitionCallback = getEnterTransitionCallback(container, from, to, isPush);
+
+        if (enterTransition == null && sharedElementTransition == null && exitTransition == null) {
+            throw new IllegalStateException("SharedElementTransitionChangeHandler must have at least one transaction.");
+        }
+
+        return mergeTransitions(isPush);
+    }
+
+    @Override
+    public void prepareForTransition(@NonNull final ViewGroup container, @Nullable final View from, @Nullable final View to, @NonNull final Transition transition, final boolean isPush, @NonNull final OnTransitionPreparedListener onTransitionPreparedListener) {
+        OnTransitionPreparedListener listener = new OnTransitionPreparedListener() {
+            @Override
+            public void onPrepared() {
+                configureTransition(container, from, to, transition, isPush);
+                onTransitionPreparedListener.onPrepared();
+            }
+        };
+
+        configureSharedElements(container, from, to, isPush);
+
+        if (to != null && to.getParent() == null && waitForTransitionNames.size() > 0) {
+            waitOnAllTransitionNames(to, listener);
+            container.addView(to);
+        } else {
+            listener.onPrepared();
+        }
+    }
+
+    @Override
+    public final void executePropertyChanges(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, @Nullable Transition transition, boolean isPush) {
+        if (to != null && removedViews.size() > 0) {
+            to.setVisibility(View.VISIBLE);
+
+            for (ViewParentPair removedView : removedViews) {
+                removedView.parent.addView(removedView.view);
+            }
+
+            removedViews.clear();
+        }
+
+        super.executePropertyChanges(container, from, to, transition, isPush);
+    }
+
+    @Override
+    public void onAbortPush(@NonNull ControllerChangeHandler newHandler, @Nullable Controller newTop) {
+        super.onAbortPush(newHandler, newTop);
+
+        removedViews.clear();
+    }
+
+    void configureTransition(@NonNull final ViewGroup container, @Nullable View from, @Nullable View to, @NonNull final Transition transition, boolean isPush) {
+        final View nonExistentView = new View(container.getContext());
+
+        List<View> fromSharedElements = new ArrayList<>();
+        List<View> toSharedElements = new ArrayList<>();
+
+        configureSharedElements(container, nonExistentView, to, from, isPush, fromSharedElements, toSharedElements);
+
+        List<View> exitingViews = exitTransition != null ? configureEnteringExitingViews(exitTransition, from, fromSharedElements, nonExistentView) : null;
+        if (exitingViews == null || exitingViews.isEmpty()) {
+            exitTransition = null;
+        }
+
+        if (enterTransition != null) {
+            enterTransition.addTarget(nonExistentView);
+        }
+
+        final List<View> enteringViews = new ArrayList<>();
+        scheduleRemoveTargets(transition, enterTransition, enteringViews, exitTransition, exitingViews, sharedElementTransition, toSharedElements);
+        scheduleTargetChange(container, to, nonExistentView, toSharedElements, enteringViews, exitingViews);
+
+        setNameOverrides(container, toSharedElements);
+        scheduleNameReset(container, toSharedElements);
+    }
+
+    private void waitOnAllTransitionNames(@NonNull final View to, @NonNull final OnTransitionPreparedListener onTransitionPreparedListener) {
+        OnPreDrawListener onPreDrawListener = new OnPreDrawListener() {
+            boolean addedSubviewListeners;
+
+            @Override
+            public boolean onPreDraw() {
+                List<View> foundViews = new ArrayList<>();
+                boolean allViewsFound = true;
+                for (String transitionName : waitForTransitionNames) {
+                    View namedView = TransitionUtils.findNamedView(to, transitionName);
+                    if (namedView != null) {
+                        foundViews.add(TransitionUtils.findNamedView(to, transitionName));
+                    } else {
+                        allViewsFound = false;
+                        break;
+                    }
+                }
+
+                if (allViewsFound && !addedSubviewListeners) {
+                    addedSubviewListeners = true;
+                    waitOnChildTransitionNames(to, foundViews, this, onTransitionPreparedListener);
+                }
+
+                return false;
+            }
+        };
+
+        to.getViewTreeObserver().addOnPreDrawListener(onPreDrawListener);
+    }
+
+    void waitOnChildTransitionNames(@NonNull final View to, @NonNull List<View> foundViews, @NonNull final OnPreDrawListener parentPreDrawListener, @NonNull final OnTransitionPreparedListener onTransitionPreparedListener) {
+        for (final View view : foundViews) {
+            OneShotPreDrawListener.add(true, view, new Runnable() {
+                @Override
+                public void run() {
+                    waitForTransitionNames.remove(ViewCompat.getTransitionName(view));
+
+                    removedViews.add(new ViewParentPair(view, (ViewGroup)view.getParent()));
+                    ((ViewGroup)view.getParent()).removeView(view);
+
+                    if (waitForTransitionNames.size() == 0) {
+                        to.getViewTreeObserver().removeOnPreDrawListener(parentPreDrawListener);
+                        to.setVisibility(View.INVISIBLE);
+                        onTransitionPreparedListener.onPrepared();
+                    }
+                }
+            });
+        }
+    }
+
+    private void scheduleTargetChange(@NonNull final ViewGroup container, @Nullable final View to, @NonNull final View nonExistentView,
+                                      @NonNull final List<View> toSharedElements, @NonNull final List<View> enteringViews, @Nullable final List<View> exitingViews) {
+        OneShotPreDrawListener.add(true, container, new Runnable() {
+            @Override
+            public void run() {
+                if (enterTransition != null) {
+                    enterTransition.removeTarget(nonExistentView);
+                    List<View> views = configureEnteringExitingViews(enterTransition, to, toSharedElements, nonExistentView);
+                    enteringViews.addAll(views);
+                }
+
+                if (exitingViews != null) {
+                    if (exitTransition != null) {
+                        List<View> tempExiting = new ArrayList<>();
+                        tempExiting.add(nonExistentView);
+                        TransitionUtils.replaceTargets(exitTransition, exitingViews, tempExiting);
+                    }
+                    exitingViews.clear();
+                    exitingViews.add(nonExistentView);
+                }
+            }
+        });
+    }
+
+    private Transition mergeTransitions(boolean isPush) {
+        boolean overlap = enterTransition == null || exitTransition == null || allowTransitionOverlap(isPush);
+
+        if (overlap) {
+            return TransitionUtils.mergeTransitions(TransitionSet.ORDERING_TOGETHER, exitTransition, enterTransition, sharedElementTransition);
+        } else {
+            Transition staggered = TransitionUtils.mergeTransitions(TransitionSet.ORDERING_SEQUENTIAL, exitTransition, enterTransition);
+            return TransitionUtils.mergeTransitions(TransitionSet.ORDERING_TOGETHER, staggered, sharedElementTransition);
+        }
+    }
+
+    @NonNull List<View> configureEnteringExitingViews(@NonNull Transition transition, @Nullable View view, @NonNull List<View> sharedElements, @NonNull View nonExistentView) {
+        List<View> viewList = new ArrayList<>();
+        if (view != null) {
+            captureTransitioningViews(viewList, view);
+        }
+        viewList.removeAll(sharedElements);
+        if (!viewList.isEmpty()) {
+            viewList.add(nonExistentView);
+            TransitionUtils.addTargets(transition, viewList);
+        }
+        return viewList;
+    }
+
+    private void configureSharedElements(@NonNull ViewGroup container, @NonNull final View nonExistentView, @Nullable final View to, @Nullable View from,
+                                         final boolean isPush, @NonNull final List<View> fromSharedElements, @NonNull final List<View> toSharedElements) {
+
+        if (to == null || from == null) {
+            return;
+        }
+
+        ArrayMap<String, View> capturedFromSharedElements = captureFromSharedElements(from);
+
+        if (sharedElementNames.isEmpty()) {
+            sharedElementTransition = null;
+        } else if (capturedFromSharedElements != null) {
+            fromSharedElements.addAll(capturedFromSharedElements.values());
+        }
+
+        if (enterTransition == null && exitTransition == null && sharedElementTransition == null) {
+            return;
+        }
+
+        callSharedElementStartEnd(capturedFromSharedElements, true);
+
+        final Rect toEpicenter;
+        if (sharedElementTransition != null) {
+            toEpicenter = new Rect();
+            TransitionUtils.setTargets(sharedElementTransition, nonExistentView, fromSharedElements);
+            setFromEpicenter(capturedFromSharedElements);
+            if (enterTransition != null) {
+                enterTransition.setEpicenterCallback(new Transition.EpicenterCallback() {
+                    @Override
+                    public Rect onGetEpicenter(Transition transition) {
+                        if (toEpicenter.isEmpty()) {
+                            return null;
+                        }
+                        return toEpicenter;
+                    }
+                });
+            }
+        } else {
+            toEpicenter = null;
+        }
+
+        OneShotPreDrawListener.add(true, container, new Runnable() {
+            @Override
+            public void run() {
+                ArrayMap<String, View> capturedToSharedElements = captureToSharedElements(to, isPush);
+
+                if (capturedToSharedElements != null) {
+                    toSharedElements.addAll(capturedToSharedElements.values());
+                    toSharedElements.add(nonExistentView);
+                }
+
+                callSharedElementStartEnd(capturedToSharedElements, false);
+                if (sharedElementTransition != null) {
+                    sharedElementTransition.getTargets().clear();
+                    sharedElementTransition.getTargets().addAll(toSharedElements);
+                    TransitionUtils.replaceTargets(sharedElementTransition, fromSharedElements, toSharedElements);
+
+                    final View toEpicenterView = getToEpicenterView(capturedToSharedElements);
+                    if (toEpicenterView != null && toEpicenter != null) {
+                        TransitionUtils.getBoundsOnScreen(toEpicenterView, toEpicenter);
+                    }
+                }
+            }
+        });
+    }
+
+    @Nullable View getToEpicenterView(@Nullable ArrayMap<String, View> toSharedElements) {
+        if (enterTransition != null && sharedElementNames.size() > 0 && toSharedElements != null) {
+            return toSharedElements.get(sharedElementNames.valueAt(0));
+        }
+        return null;
+    }
+
+    private void setFromEpicenter(@Nullable ArrayMap<String, View> fromSharedElements) {
+        if (sharedElementNames.size() > 0 && fromSharedElements != null) {
+            final View fromEpicenterView = fromSharedElements.get(sharedElementNames.keyAt(0));
+
+            if (sharedElementTransition != null) {
+                TransitionUtils.setEpicenter(sharedElementTransition, fromEpicenterView);
+            }
+
+            if (exitTransition != null) {
+                TransitionUtils.setEpicenter(exitTransition, fromEpicenterView);
+            }
+        }
+    }
+
+    @Nullable ArrayMap<String, View> captureToSharedElements(@Nullable final View to, boolean isPush) {
+        if (sharedElementNames.isEmpty() || sharedElementTransition == null || to == null) {
+            sharedElementNames.clear();
+            return null;
+        }
+
+        final ArrayMap<String, View> toSharedElements = new ArrayMap<>();
+        TransitionUtils.findNamedViews(toSharedElements, to);
+        for (ViewParentPair removedView : removedViews) {
+            toSharedElements.put(ViewCompat.getTransitionName(removedView.view), removedView.view);
+        }
+
+        final List<String> names = new ArrayList<>(sharedElementNames.values());
+
+        toSharedElements.retainAll(names);
+        if (enterTransitionCallback != null) {
+            enterTransitionCallback.onMapSharedElements(names, toSharedElements);
+            for (int i = names.size() - 1; i >= 0; i--) {
+                String name = names.get(i);
+                View view = toSharedElements.get(name);
+                if (view == null) {
+                    String key = findKeyForValue(sharedElementNames, name);
+                    if (key != null) {
+                        sharedElementNames.remove(key);
+                    }
+                } else if (!name.equals(ViewCompat.getTransitionName(view))) {
+                    String key = findKeyForValue(sharedElementNames, name);
+                    if (key != null) {
+                        sharedElementNames.put(key, ViewCompat.getTransitionName(view));
+                    }
+                }
+            }
+        } else {
+            for (int i = sharedElementNames.size() - 1; i >= 0; i--) {
+                final String targetName = sharedElementNames.valueAt(i);
+                if (!toSharedElements.containsKey(targetName)) {
+                    sharedElementNames.removeAt(i);
+                }
+            }
+        }
+        return toSharedElements;
+    }
+
+    @Nullable String findKeyForValue(@NonNull ArrayMap<String, String> map, @NonNull String value) {
+        final int numElements = map.size();
+        for (int i = 0; i < numElements; i++) {
+            if (value.equals(map.valueAt(i))) {
+                return map.keyAt(i);
+            }
+        }
+        return null;
+    }
+
+    @Nullable
+    private ArrayMap<String, View> captureFromSharedElements(@NonNull View from) {
+        if (sharedElementNames.isEmpty() || sharedElementTransition == null) {
+            sharedElementNames.clear();
+            return null;
+        }
+
+        final ArrayMap<String, View> fromSharedElements = new ArrayMap<>();
+        TransitionUtils.findNamedViews(fromSharedElements, from);
+
+        final List<String> names = new ArrayList<>(sharedElementNames.keySet());
+
+        fromSharedElements.retainAll(names);
+        if (exitTransitionCallback != null) {
+            exitTransitionCallback.onMapSharedElements(names, fromSharedElements);
+            for (int i = names.size() - 1; i >= 0; i--) {
+                String name = names.get(i);
+                View view = fromSharedElements.get(name);
+                if (view == null) {
+                    sharedElementNames.remove(name);
+                } else if (!name.equals(ViewCompat.getTransitionName(view))) {
+                    String targetValue = sharedElementNames.remove(name);
+                    sharedElementNames.put(ViewCompat.getTransitionName(view), targetValue);
+                }
+            }
+        } else {
+            sharedElementNames.retainAll(fromSharedElements.keySet());
+        }
+        return fromSharedElements;
+    }
+
+    void callSharedElementStartEnd(@Nullable ArrayMap<String, View> sharedElements, boolean isStart) {
+        if (enterTransitionCallback != null) {
+            final int count = sharedElements == null ? 0 : sharedElements.size();
+            List<View> views = new ArrayList<>(count);
+            List<String> names = new ArrayList<>(count);
+            for (int i = 0; i < count; i++) {
+                names.add(sharedElements.keyAt(i));
+                views.add(sharedElements.valueAt(i));
+            }
+            if (isStart) {
+                enterTransitionCallback.onSharedElementStart(names, views, null);
+            } else {
+                enterTransitionCallback.onSharedElementEnd(names, views, null);
+            }
+        }
+    }
+
+    private void captureTransitioningViews(@NonNull List<View> transitioningViews, @NonNull View view) {
+        if (view.getVisibility() == View.VISIBLE) {
+            if (view instanceof ViewGroup) {
+                ViewGroup viewGroup = (ViewGroup) view;
+                if (ViewGroupCompat.isTransitionGroup(viewGroup)) {
+                    transitioningViews.add(viewGroup);
+                } else {
+                    int count = viewGroup.getChildCount();
+                    for (int i = 0; i < count; i++) {
+                        View child = viewGroup.getChildAt(i);
+                        captureTransitioningViews(transitioningViews, child);
+                    }
+                }
+            } else {
+                transitioningViews.add(view);
+            }
+        }
+    }
+
+    private void scheduleRemoveTargets(@NonNull final Transition overallTransition,
+                                       @Nullable final Transition enterTransition, @Nullable final List<View> enteringViews,
+                                       @Nullable final Transition exitTransition, @Nullable final List<View> exitingViews,
+                                       @Nullable final Transition sharedElementTransition, @Nullable final List<View> toSharedElements) {
+        overallTransition.addListener(new Transition.TransitionListener() {
+            @Override
+            public void onTransitionStart(Transition transition) {
+                if (enterTransition != null && enteringViews != null) {
+                    TransitionUtils.replaceTargets(enterTransition, enteringViews, null);
+                }
+                if (exitTransition != null && exitingViews != null) {
+                    TransitionUtils.replaceTargets(exitTransition, exitingViews, null);
+                }
+                if (sharedElementTransition != null && toSharedElements != null) {
+                    TransitionUtils.replaceTargets(sharedElementTransition, toSharedElements, null);
+                }
+            }
+
+            @Override
+            public void onTransitionEnd(Transition transition) { }
+
+            @Override
+            public void onTransitionCancel(Transition transition) { }
+
+            @Override
+            public void onTransitionPause(Transition transition) { }
+
+            @Override
+            public void onTransitionResume(Transition transition) { }
+        });
+    }
+
+    private void setNameOverrides(@NonNull final View container, @NonNull final List<View> toSharedElements) {
+        OneShotPreDrawListener.add(true, container, new Runnable() {
+            @Override
+            public void run() {
+                final int numSharedElements = toSharedElements.size();
+                for (int i = 0; i < numSharedElements; i++) {
+                    View view = toSharedElements.get(i);
+                    String name = ViewCompat.getTransitionName(view);
+                    if (name != null) {
+                        String inName = findKeyForValue(sharedElementNames, name);
+                        ViewCompat.setTransitionName(view, inName);
+                    }
+                }
+            }
+        });
+    }
+
+    private void scheduleNameReset(@NonNull final ViewGroup container, @NonNull final List<View> toSharedElements) {
+        OneShotPreDrawListener.add(true, container, new Runnable() {
+            @Override
+            public void run() {
+                final int numSharedElements = toSharedElements.size();
+                for (int i = 0; i < numSharedElements; i++) {
+                    final View view = toSharedElements.get(i);
+                    final String name = ViewCompat.getTransitionName(view);
+                    final String inName = sharedElementNames.get(name);
+                    ViewCompat.setTransitionName(view, inName);
+                }
+            }
+        });
+    }
+
+    /**
+     * Will be called when views are ready to have their shared elements configured. Within this method one of the addSharedElement methods
+     * should be called for each shared element that will be used. If one or more of these shared elements will not instantly be available in
+     * the incoming view (for ex, in a RecyclerView), waitOnSharedElementNamed can be called to delay the transition until everything is available.
+     */
+    public abstract void configureSharedElements(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush);
+
+    /**
+     * Should return the transition that will be used on the exiting ("from") view, if one is desired.
+     */
+    @Nullable
+    public abstract Transition getExitTransition(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush);
+
+    /**
+     * Should return the transition that will be used on shared elements between the from and to views.
+     */
+    @Nullable
+    public abstract Transition getSharedElementTransition(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush);
+
+    /**
+     * Should return the transition that will be used on the entering ("to") view, if one is desired.
+     */
+    @Nullable
+    public abstract Transition getEnterTransition(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush);
+
+    /**
+     * Should return a callback that can be used to customize transition behavior of the shared element transition for the "from" view.
+     */
+    @Nullable
+    public SharedElementCallback getExitTransitionCallback(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush) {
+        return null;
+    }
+
+    /**
+     * Should return a callback that can be used to customize transition behavior of the shared element transition for the "to" view.
+     */
+    @Nullable
+    public SharedElementCallback getEnterTransitionCallback(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush) {
+        return null;
+    }
+
+    /**
+     * Should return whether or not the the exit transition and enter transition should overlap. If true,
+     * the enter transition will start as soon as possible. Otherwise, the enter transition will wait until the
+     * completion of the exit transition. Defaults to true.
+     */
+    public boolean allowTransitionOverlap(boolean isPush) {
+        return true;
+    }
+
+    /**
+     * Used to register an element that will take part in the shared element transition.
+     *
+     * @param name The transition name that is used for both the entering and exiting views.
+     */
+    protected final void addSharedElement(@NonNull String name) {
+        sharedElementNames.put(name, name);
+    }
+
+    /**
+     * Used to register an element that will take part in the shared element transition. Maps the name used in the
+     * "from" view to the name used in the "to" view if they are not the same.
+     *
+     * @param fromName The transition name used in the "from" view
+     * @param toName The transition name used in the "to" view
+     */
+    protected final void addSharedElement(@NonNull String fromName, @NonNull String toName) {
+        sharedElementNames.put(fromName, toName);
+    }
+
+    /**
+     * Used to register an element that will take part in the shared element transition. Maps the name used in the
+     * "from" view to the name used in the "to" view if they are not the same.
+     *
+     * @param sharedElement The view from the "from" view that will take part in the shared element transition
+     * @param toName The transition name used in the "to" view
+     */
+    protected final void addSharedElement(@NonNull View sharedElement, @NonNull String toName) {
+        String transitionName = ViewCompat.getTransitionName(sharedElement);
+        if (transitionName == null) {
+            throw new IllegalArgumentException("Unique transitionNames are required for all sharedElements");
+        }
+        sharedElementNames.put(transitionName, toName);
+    }
+
+    /**
+     * The transition will be delayed until the view with the name passed in is available in the "to" hierarchy. This is
+     * particularly useful for views that don't load instantly, like RecyclerViews. Note that using this method can
+     * potentially lock up your app indefinitely if the view never loads!
+     */
+    protected final void waitOnSharedElementNamed(@NonNull String name) {
+        if (!sharedElementNames.values().contains(name)) {
+            throw new IllegalStateException("Can't wait on a shared element that hasn't been registered using addSharedElement");
+        }
+        waitForTransitionNames.add(name);
+    }
+
+    private static class OneShotPreDrawListener implements OnPreDrawListener, View.OnAttachStateChangeListener {
+
+        private final View view;
+        private ViewTreeObserver viewTreeObserver;
+        private final Runnable runnable;
+        private final boolean preDrawReturnValue;
+
+        private OneShotPreDrawListener(boolean preDrawReturnValue, @NonNull View view, @NonNull Runnable runnable) {
+            this.preDrawReturnValue = preDrawReturnValue;
+            this.view = view;
+            viewTreeObserver = view.getViewTreeObserver();
+            this.runnable = runnable;
+        }
+
+        @NonNull
+        public static OneShotPreDrawListener add(boolean preDrawReturnValue, @NonNull View view, @NonNull Runnable runnable) {
+            OneShotPreDrawListener listener = new OneShotPreDrawListener(preDrawReturnValue, view, runnable);
+            view.getViewTreeObserver().addOnPreDrawListener(listener);
+            view.addOnAttachStateChangeListener(listener);
+            return listener;
+        }
+
+        @Override
+        public boolean onPreDraw() {
+            removeListener();
+            runnable.run();
+            return preDrawReturnValue;
+        }
+
+        private void removeListener() {
+            if (viewTreeObserver.isAlive()) {
+                viewTreeObserver.removeOnPreDrawListener(this);
+            } else {
+                view.getViewTreeObserver().removeOnPreDrawListener(this);
+            }
+            view.removeOnAttachStateChangeListener(this);
+        }
+
+        @Override
+        public void onViewAttachedToWindow(View v) {
+            viewTreeObserver = v.getViewTreeObserver();
+        }
+
+        @Override
+        public void onViewDetachedFromWindow(View v) {
+            removeListener();
+        }
+
+    }
+
+    private static class ViewParentPair {
+        @NonNull final View view;
+        @NonNull final ViewGroup parent;
+
+        ViewParentPair(@NonNull View view, ViewGroup parent) {
+            this.view = view;
+            this.parent = parent;
+        }
+    }
+
+}

conductor-modules/androidx-transition/src/main/java/com/bluelinelabs/conductor/changehandler/androidxtransition/TransitionChangeHandler.java

@@ -0,0 +1,150 @@
+package com.bluelinelabs.conductor.changehandler.androidxtransition;
+
+import android.view.View;
+import android.view.ViewGroup;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.transition.Transition;
+import androidx.transition.TransitionManager;
+
+import com.bluelinelabs.conductor.Controller;
+import com.bluelinelabs.conductor.ControllerChangeHandler;
+
+/**
+ * A base {@link ControllerChangeHandler} that facilitates using {@link Transition}s to replace Controller Views.
+ */
+public abstract class TransitionChangeHandler extends ControllerChangeHandler {
+
+    public interface OnTransitionPreparedListener {
+        void onPrepared();
+    }
+
+    boolean canceled;
+    private boolean needsImmediateCompletion;
+
+    /**
+     * Should be overridden to return the Transition to use while replacing Views.
+     *
+     * @param container The container these Views are hosted in
+     * @param from      The previous View in the container or {@code null} if there was no Controller before this transition
+     * @param to        The next View that should be put in the container or {@code null} if no Controller is being transitioned to
+     * @param isPush    True if this is a push transaction, false if it's a pop
+     */
+    @NonNull
+    protected abstract Transition getTransition(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush);
+
+    @Override
+    public void onAbortPush(@NonNull ControllerChangeHandler newHandler, @Nullable Controller newTop) {
+        super.onAbortPush(newHandler, newTop);
+
+        canceled = true;
+    }
+
+    @Override
+    public void completeImmediately() {
+        super.completeImmediately();
+
+        needsImmediateCompletion = true;
+    }
+
+    @Nullable
+    private ControllerChangeCompletedListener listener;
+
+    @Override
+    public void performChange(@NonNull final ViewGroup container, @Nullable final View from, @Nullable final View to, final boolean isPush, @NonNull final ControllerChangeCompletedListener changeListener) {
+        listener = changeListener;
+        if (canceled) {
+            changeListener.onChangeCompleted();
+            return;
+        }
+        if (needsImmediateCompletion) {
+            executePropertyChanges(container, from, to, null, isPush);
+            changeListener.onChangeCompleted();
+            return;
+        }
+
+        final Runnable onTransitionNotStarted = new Runnable() {
+            @Override
+            public void run() {
+                changeListener.onChangeCompleted();
+            }
+        };
+
+        final Transition transition = getTransition(container, from, to, isPush);
+        transition.addListener(new Transition.TransitionListener() {
+            @Override
+            public void onTransitionStart(Transition transition) {
+                container.removeCallbacks(onTransitionNotStarted);
+            }
+
+            @Override
+            public void onTransitionEnd(Transition transition) {
+                listener.onChangeCompleted();
+                listener = null;
+            }
+
+            @Override
+            public void onTransitionCancel(Transition transition) {
+                listener.onChangeCompleted();
+                listener = null;
+            }
+
+            @Override
+            public void onTransitionPause(Transition transition) { }
+
+            @Override
+            public void onTransitionResume(Transition transition) { }
+        });
+
+        prepareForTransition(container, from, to, transition, isPush, new OnTransitionPreparedListener() {
+            @Override
+            public void onPrepared() {
+                if (!canceled) {
+                    TransitionManager.beginDelayedTransition(container, transition);
+                    executePropertyChanges(container, from, to, transition, isPush);
+                    container.post(onTransitionNotStarted);
+                }
+            }
+        });
+    }
+
+    @Override
+    public boolean removesFromViewOnPush() {
+        return true;
+    }
+
+    /**
+     * Called before a transition occurs. This can be used to reorder views, set their transition names, etc. The transition will begin
+     * when {@code onTransitionPreparedListener} is called.
+     *
+     * @param container  The container these Views are hosted in
+     * @param from       The previous View in the container or {@code null} if there was no Controller before this transition
+     * @param to         The next View that should be put in the container or {@code null} if no Controller is being transitioned to
+     * @param transition The transition that is being prepared for
+     * @param isPush     True if this is a push transaction, false if it's a pop
+     */
+    public void prepareForTransition(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, @NonNull Transition transition, boolean isPush, @NonNull OnTransitionPreparedListener onTransitionPreparedListener) {
+        onTransitionPreparedListener.onPrepared();
+    }
+
+    /**
+     * This should set all view properties needed for the transition to work properly. By default it removes the "from" view
+     * and adds the "to" view.
+     *
+     * @param container  The container these Views are hosted in
+     * @param from       The previous View in the container or {@code null} if there was no Controller before this transition
+     * @param to         The next View that should be put in the container or {@code null} if no Controller is being transitioned to
+     * @param transition The transition with which {@code TransitionManager.beginDelayedTransition} has been called. This will be null only if another ControllerChangeHandler immediately overrides this one.
+     * @param isPush     True if this is a push transaction, false if it's a pop
+     */
+    public void executePropertyChanges(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, @Nullable Transition transition, boolean isPush) {
+        if (from != null && (removesFromViewOnPush() || !isPush) && from.getParent() == container) {
+            container.removeView(from);
+        }
+        if (to != null && to.getParent() == null) {
+            container.addView(to);
+        }
+    }
+
+}

conductor-modules/androidx-transition/src/main/java/com/bluelinelabs/conductor/internal/TransitionUtils.java

@@ -0,0 +1,184 @@
+package com.bluelinelabs.conductor.internal;
+
+import android.graphics.Rect;
+import android.view.View;
+import android.view.ViewGroup;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.core.view.ViewCompat;
+import androidx.transition.Transition;
+import androidx.transition.TransitionSet;
+
+import java.util.List;
+import java.util.Map;
+
+public class TransitionUtils {
+
+    public static void findNamedViews(@NonNull Map<String, View> namedViews, View view) {
+        if (view.getVisibility() == View.VISIBLE) {
+            String transitionName = ViewCompat.getTransitionName(view);
+            if (transitionName != null) {
+                namedViews.put(transitionName, view);
+            }
+
+            if (view instanceof ViewGroup) {
+                ViewGroup viewGroup = (ViewGroup) view;
+                int childCount = viewGroup.getChildCount();
+                for (int i = 0; i < childCount; i++) {
+                    View child = viewGroup.getChildAt(i);
+                    findNamedViews(namedViews, child);
+                }
+            }
+        }
+    }
+
+    @Nullable
+    public static View findNamedView(@NonNull View view, @NonNull String transitionName) {
+        if (transitionName.equals(ViewCompat.getTransitionName(view))) {
+            return view;
+        }
+
+        if (view instanceof ViewGroup) {
+            ViewGroup viewGroup = (ViewGroup) view;
+            int childCount = viewGroup.getChildCount();
+            for (int i = 0; i < childCount; i++) {
+                View viewWithTransitionName = findNamedView(viewGroup.getChildAt(i), transitionName);
+                if (viewWithTransitionName != null) {
+                    return viewWithTransitionName;
+                }
+            }
+        }
+
+        return null;
+    }
+
+    public static void setEpicenter(@NonNull Transition transition, @Nullable View view) {
+        if (view != null) {
+            final Rect epicenter = new Rect();
+            getBoundsOnScreen(view, epicenter);
+            transition.setEpicenterCallback(new Transition.EpicenterCallback() {
+                @Override
+                public Rect onGetEpicenter(Transition transition) {
+                    return epicenter;
+                }
+            });
+        }
+    }
+
+    public static void getBoundsOnScreen(@NonNull View view, @NonNull Rect epicenter) {
+        int[] loc = new int[2];
+        view.getLocationOnScreen(loc);
+        epicenter.set(loc[0], loc[1], loc[0] + view.getWidth(), loc[1] + view.getHeight());
+    }
+
+    public static void setTargets(@NonNull Transition transition, @NonNull View nonExistentView, @NonNull List<View> sharedViews) {
+        final List<View> views = transition.getTargets();
+        views.clear();
+        final int count = sharedViews.size();
+        for (int i = 0; i < count; i++) {
+            final View view = sharedViews.get(i);
+            bfsAddViewChildren(views, view);
+        }
+        views.add(nonExistentView);
+        sharedViews.add(nonExistentView);
+        addTargets(transition, sharedViews);
+    }
+
+    public static void addTargets(@Nullable Transition transition, @NonNull List<View> views) {
+        if (transition == null) {
+            return;
+        }
+        if (transition instanceof TransitionSet) {
+            TransitionSet set = (TransitionSet) transition;
+            int numTransitions = set.getTransitionCount();
+            for (int i = 0; i < numTransitions; i++) {
+                Transition child = set.getTransitionAt(i);
+                addTargets(child, views);
+            }
+        } else if (!hasSimpleTarget(transition)) {
+            List<View> targets = transition.getTargets();
+            if (isNullOrEmpty(targets)) {
+                int numViews = views.size();
+                for (int i = 0; i < numViews; i++) {
+                    transition.addTarget(views.get(i));
+                }
+            }
+        }
+    }
+
+    public static void replaceTargets(@NonNull Transition transition, @NonNull List<View> oldTargets, @Nullable List<View> newTargets) {
+        if (transition instanceof TransitionSet) {
+            TransitionSet set = (TransitionSet) transition;
+            int numTransitions = set.getTransitionCount();
+            for (int i = 0; i < numTransitions; i++) {
+                Transition child = set.getTransitionAt(i);
+                replaceTargets(child, oldTargets, newTargets);
+            }
+        } else if (!TransitionUtils.hasSimpleTarget(transition)) {
+            List<View> targets = transition.getTargets();
+            if (targets != null && targets.size() == oldTargets.size() && targets.containsAll(oldTargets)) {
+                final int targetCount = newTargets == null ? 0 : newTargets.size();
+                for (int i = 0; i < targetCount; i++) {
+                    transition.addTarget(newTargets.get(i));
+                }
+                for (int i = oldTargets.size() - 1; i >= 0; i--) {
+                    transition.removeTarget(oldTargets.get(i));
+                }
+            }
+        }
+    }
+
+    private static void bfsAddViewChildren(@NonNull final List<View> views, @NonNull final View startView) {
+        final int startIndex = views.size();
+        if (containedBeforeIndex(views, startView, startIndex)) {
+            return; // This child is already in the list, so all its children are also.
+        }
+        views.add(startView);
+        for (int index = startIndex; index < views.size(); index++) {
+            final View view = views.get(index);
+            if (view instanceof ViewGroup) {
+                ViewGroup viewGroup = (ViewGroup) view;
+                final int childCount = viewGroup.getChildCount();
+                for (int childIndex = 0; childIndex < childCount; childIndex++) {
+                    final View child = viewGroup.getChildAt(childIndex);
+                    if (!containedBeforeIndex(views, child, startIndex)) {
+                        views.add(child);
+                    }
+                }
+            }
+        }
+    }
+
+    private static boolean containedBeforeIndex(@NonNull List<View> views, View view, int maxIndex) {
+        for (int i = 0; i < maxIndex; i++) {
+            if (views.get(i) == view) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public static boolean hasSimpleTarget(@NonNull Transition transition) {
+        return !isNullOrEmpty(transition.getTargetIds())
+                || !isNullOrEmpty(transition.getTargetNames())
+                || !isNullOrEmpty(transition.getTargetTypes());
+    }
+
+    private static boolean isNullOrEmpty(@Nullable List list) {
+        return list == null || list.isEmpty();
+    }
+
+    @NonNull
+    public static TransitionSet mergeTransitions(int ordering, Transition... transitions) {
+        TransitionSet transitionSet = new TransitionSet();
+        for (Transition transition : transitions) {
+            if (transition != null) {
+                transitionSet.addTransition(transition);
+            }
+        }
+        transitionSet.setOrdering(ordering);
+        return transitionSet;
+    }
+
+}

conductor-modules/arch-components-lifecycle/build.gradle

@@ -0,0 +1,28 @@
+apply from: rootProject.file('dependencies.gradle')
+apply from: rootProject.file('gradle-mvn-push.gradle')
+
+apply plugin: 'com.android.library'
+
+android {
+    compileSdkVersion rootProject.ext.compileSdkVersion
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_7
+        targetCompatibility JavaVersion.VERSION_1_7
+    }
+
+    defaultConfig {
+        minSdkVersion rootProject.ext.minSdkVersion
+        targetSdkVersion rootProject.ext.targetSdkVersion
+        versionCode Integer.parseInt(project.VERSION_CODE)
+        versionName project.VERSION_NAME
+    }
+}
+
+dependencies {
+    api rootProject.ext.archComponentsLifecycle
+
+    implementation project(':conductor')
+}
+
+ext.artifactId = 'conductor-arch-components-lifecycle'

conductor-modules/arch-components-lifecycle/gradle.properties

@@ -0,0 +1,3 @@
+POM_NAME=Conductor Architecture Components Lifecycle Extensions
+POM_ARTIFACT_ID=conductor-archlifecycle
+POM_PACKAGING=aar

conductor-modules/arch-components-lifecycle/src/main/AndroidManifest.xml

@@ -0,0 +1,3 @@
+<manifest package="com.bluelinelabs.conductor.archlifecycle">
+    <application />
+</manifest>

conductor-modules/arch-components-lifecycle/src/main/java/com/bluelinelabs/conductor/archlifecycle/ControllerLifecycleOwner.java

@@ -0,0 +1,65 @@
+package com.bluelinelabs.conductor.archlifecycle;
+
+import androidx.lifecycle.Lifecycle;
+import androidx.lifecycle.Lifecycle.Event;
+import androidx.lifecycle.LifecycleOwner;
+import androidx.lifecycle.LifecycleRegistry;
+import android.content.Context;
+import androidx.annotation.NonNull;
+import android.view.View;
+
+import com.bluelinelabs.conductor.Controller;
+import com.bluelinelabs.conductor.Controller.LifecycleListener;
+
+public class ControllerLifecycleOwner implements LifecycleOwner {
+
+    private final LifecycleRegistry lifecycleRegistry;
+
+    public <T extends Controller & LifecycleOwner> ControllerLifecycleOwner(@NonNull T lifecycleController) {
+        lifecycleRegistry = new LifecycleRegistry(lifecycleController); // --> State.INITIALIZED
+
+        lifecycleController.addLifecycleListener(new LifecycleListener() {
+            @Override
+            public void postContextAvailable(@NonNull Controller controller, @NonNull Context context) {
+                lifecycleRegistry.handleLifecycleEvent(Event.ON_CREATE); // --> State.CREATED;
+            }
+
+            @Override
+            public void postCreateView(@NonNull Controller controller, @NonNull View view) {
+                lifecycleRegistry.handleLifecycleEvent(Event.ON_START); // --> State.STARTED;
+            }
+
+            @Override
+            public void postAttach(@NonNull Controller controller, @NonNull View view) {
+                lifecycleRegistry.handleLifecycleEvent(Event.ON_RESUME); // --> State.RESUMED;
+            }
+
+            @Override
+            public void preDetach(@NonNull Controller controller, @NonNull View view) {
+                lifecycleRegistry.handleLifecycleEvent(Event.ON_PAUSE); // --> State.STARTED;
+            }
+
+            @Override
+            public void preDestroyView(@NonNull Controller controller, @NonNull View view) {
+                lifecycleRegistry.handleLifecycleEvent(Event.ON_STOP); // --> State.CREATED;
+            }
+
+            @Override
+            public void preContextUnavailable(@NonNull Controller controller, @NonNull Context context) {
+                // do nothing
+            }
+
+            @Override
+            public void preDestroy(@NonNull Controller controller) {
+                lifecycleRegistry.handleLifecycleEvent(Event.ON_DESTROY); // --> State.DESTROYED;
+            }
+
+        });
+    }
+
+    @Override @NonNull
+    public Lifecycle getLifecycle() {
+        return lifecycleRegistry;
+    }
+
+}

conductor-modules/arch-components-lifecycle/src/main/java/com/bluelinelabs/conductor/archlifecycle/LifecycleController.java

@@ -0,0 +1,28 @@
+package com.bluelinelabs.conductor.archlifecycle;
+
+import androidx.lifecycle.Lifecycle;
+import androidx.lifecycle.LifecycleOwner;
+import android.os.Bundle;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.bluelinelabs.conductor.Controller;
+
+public abstract class LifecycleController extends Controller implements LifecycleOwner {
+
+    private final ControllerLifecycleOwner lifecycleOwner = new ControllerLifecycleOwner(this);
+
+    public LifecycleController() {
+        super();
+    }
+
+    public LifecycleController(@Nullable Bundle args) {
+        super(args);
+    }
+
+    @Override @NonNull
+    public Lifecycle getLifecycle() {
+        return lifecycleOwner.getLifecycle();
+    }
+
+}

conductor-modules/arch-components-lifecycle/src/main/java/com/bluelinelabs/conductor/archlifecycle/LifecycleRestoreViewOnCreateController.java

@@ -0,0 +1,28 @@
+package com.bluelinelabs.conductor.archlifecycle;
+
+import androidx.lifecycle.Lifecycle;
+import androidx.lifecycle.LifecycleOwner;
+import android.os.Bundle;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.bluelinelabs.conductor.RestoreViewOnCreateController;
+
+public abstract class LifecycleRestoreViewOnCreateController extends RestoreViewOnCreateController implements LifecycleOwner {
+
+    private final ControllerLifecycleOwner mLifecycleOwner = new ControllerLifecycleOwner(this);
+
+    public LifecycleRestoreViewOnCreateController() {
+        super();
+    }
+
+    public LifecycleRestoreViewOnCreateController(@Nullable Bundle args) {
+        super(args);
+    }
+
+    @Override @NonNull
+    public Lifecycle getLifecycle() {
+        return mLifecycleOwner.getLifecycle();
+    }
+
+}

conductor-modules/autodispose/build.gradle

@@ -0,0 +1,30 @@
+apply from: rootProject.file('dependencies.gradle')
+apply from: rootProject.file('gradle-mvn-push.gradle')
+
+apply plugin: 'com.android.library'
+
+android {
+    compileSdkVersion rootProject.ext.compileSdkVersion
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_7
+        targetCompatibility JavaVersion.VERSION_1_7
+    }
+
+    defaultConfig {
+        minSdkVersion rootProject.ext.minSdkVersion
+        targetSdkVersion rootProject.ext.targetSdkVersion
+        versionCode Integer.parseInt(project.VERSION_CODE)
+        versionName project.VERSION_NAME
+    }
+}
+
+dependencies {
+    api rootProject.ext.rxJava2
+    api rootProject.ext.autodispose
+    api rootProject.ext.autodisposeLifecycle
+
+    implementation project(':conductor')
+}
+
+ext.artifactId = 'conductor-autodispose'

conductor-modules/autodispose/gradle.properties

@@ -0,0 +1,3 @@
+POM_NAME=Conductor AutoDispose Extensions
+POM_ARTIFACT_ID=conductor-autodispose
+POM_PACKAGING=aar

conductor-modules/autodispose/src/main/AndroidManifest.xml

@@ -0,0 +1,3 @@
+<manifest package="com.bluelinelabs.conductor.autodispose">
+    <application />
+</manifest>

conductor-modules/autodispose/src/main/java/com/bluelinelabs/conductor/autodispose/ControllerEvent.java

@@ -0,0 +1,14 @@
+package com.bluelinelabs.conductor.autodispose;
+
+public enum ControllerEvent {
+
+    CREATE,
+    CONTEXT_AVAILABLE,
+    CREATE_VIEW,
+    ATTACH,
+    DETACH,
+    DESTROY_VIEW,
+    CONTEXT_UNAVAILABLE,
+    DESTROY
+
+}

conductor-modules/autodispose/src/main/java/com/bluelinelabs/conductor/autodispose/ControllerLifecycleSubjectHelper.java

@@ -0,0 +1,71 @@
+package com.bluelinelabs.conductor.autodispose;
+
+import android.content.Context;
+import androidx.annotation.NonNull;
+import android.view.View;
+
+import com.bluelinelabs.conductor.Controller;
+import com.uber.autodispose.OutsideScopeException;
+
+import io.reactivex.subjects.BehaviorSubject;
+
+public class ControllerLifecycleSubjectHelper {
+    private ControllerLifecycleSubjectHelper() { }
+
+    @NonNull
+    public static BehaviorSubject<ControllerEvent> create(@NonNull Controller controller) {
+        ControllerEvent initialState;
+        if (controller.isBeingDestroyed() || controller.isDestroyed()) {
+            throw new OutsideScopeException("Cannot bind to Controller lifecycle when outside of it.");
+        } else if (controller.isAttached()) {
+            initialState = ControllerEvent.ATTACH;
+        } else if (controller.getView() != null) {
+            initialState = ControllerEvent.CREATE_VIEW;
+        } else if (controller.getActivity() != null) {
+            initialState = ControllerEvent.CONTEXT_AVAILABLE;
+        } else {
+            initialState = ControllerEvent.CREATE;
+        }
+
+        final BehaviorSubject<ControllerEvent> subject = BehaviorSubject.createDefault(initialState);
+
+        controller.addLifecycleListener(new Controller.LifecycleListener() {
+            @Override
+            public void preContextAvailable(@NonNull Controller controller) {
+                subject.onNext(ControllerEvent.CONTEXT_AVAILABLE);
+            }
+
+            @Override
+            public void preCreateView(@NonNull Controller controller) {
+                subject.onNext(ControllerEvent.CREATE_VIEW);
+            }
+
+            @Override
+            public void preAttach(@NonNull Controller controller, @NonNull View view) {
+                subject.onNext(ControllerEvent.ATTACH);
+            }
+
+            @Override
+            public void preDetach(@NonNull Controller controller, @NonNull View view) {
+                subject.onNext(ControllerEvent.DETACH);
+            }
+
+            @Override
+            public void preDestroyView(@NonNull Controller controller, @NonNull View view) {
+                subject.onNext(ControllerEvent.DESTROY_VIEW);
+            }
+
+            @Override
+            public void preContextUnavailable(@NonNull Controller controller, @NonNull Context context) {
+                subject.onNext(ControllerEvent.CONTEXT_UNAVAILABLE);
+            }
+
+            @Override
+            public void preDestroy(@NonNull Controller controller) {
+                subject.onNext(ControllerEvent.DESTROY);
+            }
+        });
+
+        return subject;
+    }
+}

conductor-modules/autodispose/src/main/java/com/bluelinelabs/conductor/autodispose/ControllerScopeProvider.java

@@ -0,0 +1,81 @@
+package com.bluelinelabs.conductor.autodispose;
+
+import androidx.annotation.NonNull;
+
+import com.bluelinelabs.conductor.Controller;
+import com.uber.autodispose.OutsideScopeException;
+import com.uber.autodispose.lifecycle.LifecycleScopeProvider;
+import com.uber.autodispose.lifecycle.LifecycleScopes;
+import com.uber.autodispose.lifecycle.CorrespondingEventsFunction;
+
+import io.reactivex.CompletableSource;
+import io.reactivex.Observable;
+import io.reactivex.subjects.BehaviorSubject;
+
+public class ControllerScopeProvider implements LifecycleScopeProvider<ControllerEvent> {
+    private static final CorrespondingEventsFunction<ControllerEvent> CORRESPONDING_EVENTS =
+            new CorrespondingEventsFunction<ControllerEvent>() {
+                @Override
+                public ControllerEvent apply(ControllerEvent lastEvent) throws OutsideScopeException {
+                    switch (lastEvent) {
+                        case CREATE:
+                            return ControllerEvent.DESTROY;
+                        case CONTEXT_AVAILABLE:
+                            return ControllerEvent.CONTEXT_UNAVAILABLE;
+                        case CREATE_VIEW:
+                            return ControllerEvent.DESTROY_VIEW;
+                        case ATTACH:
+                            return ControllerEvent.DETACH;
+                        case DETACH:
+                            return ControllerEvent.DESTROY;
+                        default:
+                            throw new OutsideScopeException("Cannot bind to Controller lifecycle when outside of it.");
+                    }
+                }
+            };
+
+    @NonNull private final BehaviorSubject<ControllerEvent> lifecycleSubject;
+    @NonNull private final CorrespondingEventsFunction<ControllerEvent> correspondingEventsFunction;
+
+    public static ControllerScopeProvider from(@NonNull Controller controller) {
+        return new ControllerScopeProvider(controller, CORRESPONDING_EVENTS);
+    }
+
+    public static ControllerScopeProvider from(@NonNull Controller controller, @NonNull final ControllerEvent untilEvent) {
+        return new ControllerScopeProvider(controller, new CorrespondingEventsFunction<ControllerEvent>() {
+            @Override
+            public ControllerEvent apply(ControllerEvent controllerEvent) {
+                return untilEvent;
+            }
+        });
+    }
+
+    public static ControllerScopeProvider from(@NonNull Controller controller, @NonNull final CorrespondingEventsFunction<ControllerEvent> correspondingEventsFunction) {
+        return new ControllerScopeProvider(controller, correspondingEventsFunction);
+    }
+
+    private ControllerScopeProvider(@NonNull Controller controller, @NonNull CorrespondingEventsFunction<ControllerEvent> correspondingEventsFunction) {
+        lifecycleSubject = ControllerLifecycleSubjectHelper.create(controller);
+        this.correspondingEventsFunction = correspondingEventsFunction;
+    }
+
+    @Override
+    public Observable<ControllerEvent> lifecycle() {
+        return lifecycleSubject.hide();
+    }
+
+    @Override
+    public CorrespondingEventsFunction<ControllerEvent> correspondingEvents() {
+        return correspondingEventsFunction;
+    }
+
+    @Override
+    public ControllerEvent peekLifecycle() {
+        return lifecycleSubject.getValue();
+    }
+
+    @Override
+    public CompletableSource requestScope() throws Exception {
+        return LifecycleScopes.resolveScopeFromLifecycle(this);
+    }
+}

conductor-modules/rxlifecycle/build.gradle

@@ -5,7 +5,6 @@ apply plugin: 'com.android.library'
 
 android {
     compileSdkVersion rootProject.ext.compileSdkVersion
-    buildToolsVersion rootProject.ext.buildToolsVersion
 
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_7
@@ -21,12 +20,11 @@ android {
 }
 
 dependencies {
-    compile rootProject.ext.rxJava
-    compile rootProject.ext.rxLifecycle
-    compile rootProject.ext.rxLifecycleAndroid
+    api rootProject.ext.rxJava
+    api rootProject.ext.rxLifecycle
+    api rootProject.ext.rxLifecycleAndroid
 
-    compile project(':conductor')
+    implementation project(':conductor')
 }
 
 ext.artifactId = 'conductor-rxlifecycle'
-

conductor-modules/rxlifecycle/src/main/AndroidManifest.xml

@@ -1,3 +1,3 @@
 <manifest package="com.bluelinelabs.conductor.rxlifecycle">
     <application />
-</manifest>
+</manifest>

conductor-modules/rxlifecycle/src/main/java/com/bluelinelabs/conductor/rxlifecycle/ControllerEvent.java

@@ -3,10 +3,12 @@ package com.bluelinelabs.conductor.rxlifecycle;
 public enum ControllerEvent {
 
     CREATE,
+    CONTEXT_AVAILABLE,
     CREATE_VIEW,
     ATTACH,
     DETACH,
     DESTROY_VIEW,
+    CONTEXT_UNAVAILABLE,
     DESTROY
 
 }

conductor-modules/rxlifecycle/src/main/java/com/bluelinelabs/conductor/rxlifecycle/ControllerLifecycleSubjectHelper.java

@@ -1,10 +1,12 @@
 package com.bluelinelabs.conductor.rxlifecycle;
 
-import android.support.annotation.NonNull;
+import android.content.Context;
+import androidx.annotation.NonNull;
 import android.view.View;
 
 import com.bluelinelabs.conductor.Controller;
 import com.bluelinelabs.conductor.Controller.LifecycleListener;
+import com.trello.rxlifecycle.OutsideLifecycleException;
 
 import rx.subjects.BehaviorSubject;
 
@@ -17,9 +19,27 @@ public class ControllerLifecycleSubjectHelper {
     private ControllerLifecycleSubjectHelper() { }
 
     public static BehaviorSubject<ControllerEvent> create(Controller controller) {
-        final BehaviorSubject<ControllerEvent> subject = BehaviorSubject.create(ControllerEvent.CREATE);
+        ControllerEvent initialState;
+        if (controller.isBeingDestroyed() || controller.isDestroyed()) {
+            throw new OutsideLifecycleException("Cannot bind to Controller lifecycle when outside of it.");
+        } else if (controller.isAttached()) {
+            initialState = ControllerEvent.ATTACH;
+        } else if (controller.getView() != null) {
+            initialState = ControllerEvent.CREATE_VIEW;
+        } else if (controller.getActivity() != null) {
+            initialState = ControllerEvent.CONTEXT_AVAILABLE;
+        } else {
+            initialState = ControllerEvent.CREATE;
+        }
+
+        final BehaviorSubject<ControllerEvent> subject = BehaviorSubject.create(initialState);
 
         controller.addLifecycleListener(new LifecycleListener() {
+            @Override
+            public void preContextAvailable(@NonNull Controller controller) {
+                subject.onNext(ControllerEvent.CONTEXT_AVAILABLE);
+            }
+
             @Override
             public void preCreateView(@NonNull Controller controller) {
                 subject.onNext(ControllerEvent.CREATE_VIEW);
@@ -40,6 +60,11 @@ public class ControllerLifecycleSubjectHelper {
                 subject.onNext(ControllerEvent.DESTROY_VIEW);
             }
 
+            @Override
+            public void preContextUnavailable(@NonNull Controller controller, @NonNull Context context) {
+                subject.onNext(ControllerEvent.CONTEXT_UNAVAILABLE);
+            }
+
             @Override
             public void preDestroy(@NonNull Controller controller) {
                 subject.onNext(ControllerEvent.DESTROY);

conductor-modules/rxlifecycle/src/main/java/com/bluelinelabs/conductor/rxlifecycle/RxController.java

@@ -1,8 +1,8 @@
 package com.bluelinelabs.conductor.rxlifecycle;
 
 import android.os.Bundle;
-import android.support.annotation.CheckResult;
-import android.support.annotation.NonNull;
+import androidx.annotation.CheckResult;
+import androidx.annotation.NonNull;
 
 import com.bluelinelabs.conductor.Controller;
 import com.trello.rxlifecycle.LifecycleProvider;
@@ -49,4 +49,4 @@ public abstract class RxController extends Controller implements LifecycleProvid
         return RxControllerLifecycle.bindController(lifecycleSubject);
     }
 
-}
+}

conductor-modules/rxlifecycle/src/main/java/com/bluelinelabs/conductor/rxlifecycle/RxControllerLifecycle.java

@@ -1,7 +1,7 @@
 package com.bluelinelabs.conductor.rxlifecycle;
 
-import android.support.annotation.CheckResult;
-import android.support.annotation.NonNull;
+import androidx.annotation.CheckResult;
+import androidx.annotation.NonNull;
 
 import com.trello.rxlifecycle.LifecycleTransformer;
 import com.trello.rxlifecycle.OutsideLifecycleException;
@@ -17,7 +17,7 @@ public class RxControllerLifecycle {
      * {@link com.trello.rxlifecycle.android.RxLifecycleAndroid#bindFragment(Observable)}.
      *
      * @param lifecycle the lifecycle sequence of a Controller
-     * @return a reusable {@link Observable.Transformer} that unsubscribes the source during the Controller lifecycle
+     * @return a reusable {@link rx.Observable.Transformer} that unsubscribes the source during the Controller lifecycle
      */
     @NonNull
     @CheckResult
@@ -32,6 +32,8 @@ public class RxControllerLifecycle {
                     switch (lastEvent) {
                         case CREATE:
                             return ControllerEvent.DESTROY;
+                        case CONTEXT_AVAILABLE:
+                            return ControllerEvent.CONTEXT_UNAVAILABLE;
                         case ATTACH:
                             return ControllerEvent.DETACH;
                         case CREATE_VIEW:

conductor-modules/rxlifecycle/src/main/java/com/bluelinelabs/conductor/rxlifecycle/RxRestoreViewOnCreateController.java

@@ -1,8 +1,8 @@
 package com.bluelinelabs.conductor.rxlifecycle;
 
 import android.os.Bundle;
-import android.support.annotation.CheckResult;
-import android.support.annotation.NonNull;
+import androidx.annotation.CheckResult;
+import androidx.annotation.NonNull;
 
 import com.bluelinelabs.conductor.RestoreViewOnCreateController;
 import com.trello.rxlifecycle.LifecycleProvider;
@@ -49,4 +49,4 @@ public abstract class RxRestoreViewOnCreateController extends RestoreViewOnCreat
         return RxControllerLifecycle.bindController(lifecycleSubject);
     }
 
-}
+}

conductor-modules/rxlifecycle2/build.gradle

@@ -5,7 +5,6 @@ apply plugin: 'com.android.library'
 
 android {
     compileSdkVersion rootProject.ext.compileSdkVersion
-    buildToolsVersion rootProject.ext.buildToolsVersion
 
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_7
@@ -21,11 +20,11 @@ android {
 }
 
 dependencies {
-    compile rootProject.ext.rxJava2
-    compile rootProject.ext.rxLifecycle2
-    compile rootProject.ext.rxLifecycleAndroid2
+    api rootProject.ext.rxJava2
+    api rootProject.ext.rxLifecycle2
+    api rootProject.ext.rxLifecycleAndroid2
 
-    compile project(':conductor')
+    implementation project(':conductor')
 }
 
 ext.artifactId = 'conductor-rxlifecycle2'

conductor-modules/rxlifecycle2/src/main/AndroidManifest.xml

@@ -1,4 +1,3 @@
 <manifest package="com.bluelinelabs.conductor.rxlifecycle2">
     <application />
 </manifest>
-

conductor-modules/rxlifecycle2/src/main/java/com/bluelinelabs/conductor/rxlifecycle2/ControllerEvent.java

@@ -3,10 +3,12 @@ package com.bluelinelabs.conductor.rxlifecycle2;
 public enum ControllerEvent {
 
     CREATE,
+    CONTEXT_AVAILABLE,
     CREATE_VIEW,
     ATTACH,
     DETACH,
     DESTROY_VIEW,
+    CONTEXT_UNAVAILABLE,
     DESTROY
 
 }

conductor-modules/rxlifecycle2/src/main/java/com/bluelinelabs/conductor/rxlifecycle2/ControllerLifecycleSubjectHelper.java

@@ -1,18 +1,40 @@
 package com.bluelinelabs.conductor.rxlifecycle2;
 
-import android.support.annotation.NonNull;
+import android.content.Context;
+import androidx.annotation.NonNull;
 import android.view.View;
+
 import com.bluelinelabs.conductor.Controller;
+import com.trello.rxlifecycle2.OutsideLifecycleException;
+
 import io.reactivex.subjects.BehaviorSubject;
 
 public class ControllerLifecycleSubjectHelper {
     private ControllerLifecycleSubjectHelper() {
     }
 
-    public static BehaviorSubject<ControllerEvent> create(Controller controller){
-        final BehaviorSubject<ControllerEvent> subject = BehaviorSubject.createDefault(ControllerEvent.CREATE);
+    public static BehaviorSubject<ControllerEvent> create(Controller controller) {
+        ControllerEvent initialState;
+        if (controller.isBeingDestroyed() || controller.isDestroyed()) {
+            throw new OutsideLifecycleException("Cannot bind to Controller lifecycle when outside of it.");
+        } else if (controller.isAttached()) {
+            initialState = ControllerEvent.ATTACH;
+        } else if (controller.getView() != null) {
+            initialState = ControllerEvent.CREATE_VIEW;
+        } else if (controller.getActivity() != null) {
+            initialState = ControllerEvent.CONTEXT_AVAILABLE;
+        } else {
+            initialState = ControllerEvent.CREATE;
+        }
+
+        final BehaviorSubject<ControllerEvent> subject = BehaviorSubject.createDefault(initialState);
 
         controller.addLifecycleListener(new Controller.LifecycleListener() {
+            @Override
+            public void preContextAvailable(@NonNull Controller controller) {
+                subject.onNext(ControllerEvent.CONTEXT_AVAILABLE);
+            }
+
             @Override
             public void preCreateView(@NonNull Controller controller) {
                 subject.onNext(ControllerEvent.CREATE_VIEW);
@@ -33,6 +55,11 @@ public class ControllerLifecycleSubjectHelper {
                 subject.onNext(ControllerEvent.DESTROY_VIEW);
             }
 
+            @Override
+            public void preContextUnavailable(@NonNull Controller controller, @NonNull Context context) {
+                subject.onNext(ControllerEvent.CONTEXT_UNAVAILABLE);
+            }
+
             @Override
             public void preDestroy(@NonNull Controller controller) {
                 subject.onNext(ControllerEvent.DESTROY);

conductor-modules/rxlifecycle2/src/main/java/com/bluelinelabs/conductor/rxlifecycle2/RxController.java

@@ -1,9 +1,9 @@
 package com.bluelinelabs.conductor.rxlifecycle2;
 
 import android.os.Bundle;
-import android.support.annotation.CheckResult;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.CheckResult;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import com.bluelinelabs.conductor.Controller;
 import com.trello.rxlifecycle2.LifecycleProvider;
 import com.trello.rxlifecycle2.LifecycleTransformer;

conductor-modules/rxlifecycle2/src/main/java/com/bluelinelabs/conductor/rxlifecycle2/RxControllerLifecycle.java

@@ -1,6 +1,6 @@
 package com.bluelinelabs.conductor.rxlifecycle2;
 
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 import com.trello.rxlifecycle2.LifecycleTransformer;
 import com.trello.rxlifecycle2.OutsideLifecycleException;
 import com.trello.rxlifecycle2.RxLifecycle;
@@ -27,6 +27,8 @@ public class RxControllerLifecycle {
                 switch (lastEvent) {
                     case CREATE:
                         return ControllerEvent.DESTROY;
+                    case CONTEXT_AVAILABLE:
+                        return ControllerEvent.CONTEXT_UNAVAILABLE;
                     case ATTACH:
                         return ControllerEvent.DETACH;
                     case CREATE_VIEW:

conductor-modules/rxlifecycle2/src/main/java/com/bluelinelabs/conductor/rxlifecycle2/RxRestoreViewOnCreateController.java

@@ -1,8 +1,8 @@
 package com.bluelinelabs.conductor.rxlifecycle2;
 
 import android.os.Bundle;
-import android.support.annotation.CheckResult;
-import android.support.annotation.NonNull;
+import androidx.annotation.CheckResult;
+import androidx.annotation.NonNull;
 import com.bluelinelabs.conductor.RestoreViewOnCreateController;
 import com.trello.rxlifecycle2.LifecycleProvider;
 import com.trello.rxlifecycle2.LifecycleTransformer;

conductor-modules/viewpager/build.gradle

@@ -3,7 +3,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'de.mobilej.unmock:UnMockPlugin:0.3.6'
+        classpath 'de.mobilej.unmock:UnMockPlugin:0.6.5'
     }
 }
 
@@ -12,7 +12,6 @@ apply plugin: 'de.mobilej.unmock'
 
 android {
     compileSdkVersion rootProject.ext.compileSdkVersion
-    buildToolsVersion rootProject.ext.buildToolsVersion
 
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_7
@@ -28,22 +27,14 @@ android {
 }
 
 dependencies {
-    testCompile rootProject.ext.junit
-    testCompile rootProject.ext.roboelectric
+    testImplementation rootProject.ext.junit
+    testImplementation rootProject.ext.roboelectric
 
-    compile rootProject.ext.supportAppCompat
-    compile project(':conductor')
+    implementation rootProject.ext.androidxAppCompat
+    implementation project(':conductor')
 }
 
-unMock {
-    downloadFrom 'https://oss.sonatype.org/content/groups/public/org/robolectric/android-all/4.3_r2-robolectric-0/android-all-4.3_r2-robolectric-0.jar'
-
-    keep "android.os.Bundle"
-    keep "android.os.BaseBundle"
-}
-
-ext.artifactId = 'conductor-support'
+ext.artifactId = 'conductor-viewpager'
 
 apply from: rootProject.file('dependencies.gradle')
 apply from: rootProject.file('gradle-mvn-push.gradle')
-

conductor-modules/viewpager/gradle.properties

@@ -0,0 +1,3 @@
+POM_NAME=Conductor PagerAdapter
+POM_ARTIFACT_ID=conductor-viewpager
+POM_PACKAGING=aar

conductor-modules/viewpager/src/main/AndroidManifest.xml

@@ -1,3 +1,3 @@
 <manifest package="com.bluelinelabs.conductor.support">
     <application />
-</manifest>
+</manifest>

conductor-modules/viewpager/src/main/java/com/bluelinelabs/conductor/support/RouterPagerAdapter.java

@@ -2,9 +2,6 @@ package com.bluelinelabs.conductor.support;
 
 import android.os.Bundle;
 import android.os.Parcelable;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
-import android.support.v4.view.PagerAdapter;
 import android.util.SparseArray;
 import android.view.View;
 import android.view.ViewGroup;
@@ -14,7 +11,13 @@ import com.bluelinelabs.conductor.Router;
 import com.bluelinelabs.conductor.RouterTransaction;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.viewpager.widget.PagerAdapter;
 
 /**
  * An adapter for ViewPagers that uses Routers as pages
@@ -22,14 +25,18 @@ import java.util.List;
 public abstract class RouterPagerAdapter extends PagerAdapter {
 
     private static final String KEY_SAVED_PAGES = "RouterPagerAdapter.savedStates";
+    private static final String KEY_TAGS_KEYS = "RouterPagerAdapter.tags.keys";
+    private static final String KEY_TAGS_VALUES = "RouterPagerAdapter.tags.values";
     private static final String KEY_MAX_PAGES_TO_STATE_SAVE = "RouterPagerAdapter.maxPagesToStateSave";
     private static final String KEY_SAVE_PAGE_HISTORY = "RouterPagerAdapter.savedPageHistory";
 
     private final Controller host;
     private int maxPagesToStateSave = Integer.MAX_VALUE;
+    private Map<Integer, String> tags = new HashMap<>();
     private SparseArray<Bundle> savedPages = new SparseArray<>();
     private SparseArray<Router> visibleRouters = new SparseArray<>();
     private ArrayList<Integer> savedPageHistory = new ArrayList<>();
+    private Router currentPrimaryRouter;
 
     /**
      * Creates a new RouterPagerAdapter using the passed host.
@@ -64,6 +71,12 @@ public abstract class RouterPagerAdapter extends PagerAdapter {
     public Object instantiateItem(ViewGroup container, int position) {
         final String name = makeRouterName(container.getId(), getItemId(position));
 
+        // Ensure we don't try to restore state for a router with a different ID just because
+        // the position was reused. Fixes https://github.com/bluelinelabs/Conductor/issues/582
+        if (tags.get(position) != null && !tags.get(position).equals(name)) {
+            savedPages.remove(position);
+        }
+
         Router router = host.getChildRouter(container, name);
         if (!router.hasRootController()) {
             Bundle routerSavedState = savedPages.get(position);
@@ -71,12 +84,20 @@ public abstract class RouterPagerAdapter extends PagerAdapter {
             if (routerSavedState != null) {
                 router.restoreInstanceState(routerSavedState);
                 savedPages.remove(position);
+                savedPageHistory.remove((Integer) position);
             }
         }
 
         router.rebindIfNeeded();
         configureRouter(router, position);
 
+        if (router != currentPrimaryRouter) {
+            for (RouterTransaction transaction : router.getBackstack()) {
+                transaction.controller().setOptionsMenuHidden(true);
+            }
+        }
+
+        tags.put(position, name);
         visibleRouters.put(position, router);
         return router;
     }
@@ -89,7 +110,7 @@ public abstract class RouterPagerAdapter extends PagerAdapter {
         router.saveInstanceState(savedState);
         savedPages.put(position, savedState);
 
-        savedPageHistory.remove((Integer)position);
+        savedPageHistory.remove((Integer) position);
         savedPageHistory.add(position);
 
         ensurePagesSaved();
@@ -99,6 +120,24 @@ public abstract class RouterPagerAdapter extends PagerAdapter {
         visibleRouters.remove(position);
     }
 
+    @Override
+    public void setPrimaryItem(ViewGroup container, int position, Object object) {
+        Router router = (Router)object;
+        if (router != currentPrimaryRouter) {
+            if (currentPrimaryRouter != null) {
+                for (RouterTransaction transaction : currentPrimaryRouter.getBackstack()) {
+                    transaction.controller().setOptionsMenuHidden(true);
+                }
+            }
+            if (router != null) {
+                for (RouterTransaction transaction : router.getBackstack()) {
+                    transaction.controller().setOptionsMenuHidden(false);
+                }
+            }
+            currentPrimaryRouter = router;
+        }
+    }
+
     @Override
     public boolean isViewFromObject(View view, Object object) {
         Router router = (Router)object;
@@ -115,6 +154,8 @@ public abstract class RouterPagerAdapter extends PagerAdapter {
     public Parcelable saveState() {
         Bundle bundle = new Bundle();
         bundle.putSparseParcelableArray(KEY_SAVED_PAGES, savedPages);
+        bundle.putIntegerArrayList(KEY_TAGS_KEYS, new ArrayList<>(tags.keySet()));
+        bundle.putStringArrayList(KEY_TAGS_VALUES, new ArrayList<>(tags.values()));
         bundle.putInt(KEY_MAX_PAGES_TO_STATE_SAVE, maxPagesToStateSave);
         bundle.putIntegerArrayList(KEY_SAVE_PAGE_HISTORY, savedPageHistory);
         return bundle;
@@ -127,6 +168,14 @@ public abstract class RouterPagerAdapter extends PagerAdapter {
             savedPages = bundle.getSparseParcelableArray(KEY_SAVED_PAGES);
             maxPagesToStateSave = bundle.getInt(KEY_MAX_PAGES_TO_STATE_SAVE);
             savedPageHistory = bundle.getIntegerArrayList(KEY_SAVE_PAGE_HISTORY);
+
+            List<Integer> tagsKeys = bundle.getIntegerArrayList(KEY_TAGS_KEYS);
+            List<String> tagsValues = bundle.getStringArrayList(KEY_TAGS_VALUES);
+            if (tagsKeys != null && tagsValues != null && tagsKeys.size() == tagsValues.size()) {
+                for (int i = 0; i < tagsKeys.size(); i++) {
+                    tags.put(tagsKeys.get(i), tagsValues.get(i));
+                }
+            }
         }
     }
 
@@ -158,4 +207,4 @@ public abstract class RouterPagerAdapter extends PagerAdapter {
         return viewId + ":" + id;
     }
 
-}
+}

conductor-modules/viewpager/src/test/java/com/bluelinelabs/conductor/support/StateSaveTests.java

@@ -2,7 +2,7 @@ package com.bluelinelabs.conductor.support;
 
 import android.app.Activity;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 import android.util.SparseArray;
 import android.widget.FrameLayout;
 
@@ -17,8 +17,8 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.robolectric.Robolectric;
 import org.robolectric.RobolectricTestRunner;
+import org.robolectric.android.controller.ActivityController;
 import org.robolectric.annotation.Config;
-import org.robolectric.util.ActivityController;
 
 import static org.junit.Assert.assertEquals;
 

conductor-modules/viewpager/src/test/java/com/bluelinelabs/conductor/support/util/TestController.java

@@ -1,6 +1,6 @@
 package com.bluelinelabs.conductor.support.util;
 
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -10,7 +10,7 @@ import com.bluelinelabs.conductor.Controller;
 
 public class TestController extends Controller {
 
-    @NonNull @Override
+    @Override @NonNull
     protected View onCreateView(@NonNull LayoutInflater inflater, @NonNull ViewGroup container) {
         return new FrameLayout(inflater.getContext());
     }

conductor-support/gradle.properties

@@ -1,3 +0,0 @@
-POM_NAME=Conductor Support Extensions
-POM_ARTIFACT_ID=conductor-support
-POM_PACKAGING=aar

conductor-support/src/main/java/com/bluelinelabs/conductor/support/ControllerPagerAdapter.java

@@ -1,154 +0,0 @@
-package com.bluelinelabs.conductor.support;
-
-import android.os.Bundle;
-import android.os.Parcelable;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
-import android.support.v4.view.PagerAdapter;
-import android.util.SparseArray;
-import android.view.View;
-import android.view.ViewGroup;
-
-import com.bluelinelabs.conductor.Controller;
-import com.bluelinelabs.conductor.Router;
-import com.bluelinelabs.conductor.RouterTransaction;
-
-/**
- * @deprecated Use RouterPagerAdapter instead! This implementation was too limited and had too many
- * gotchas associated with it.
- *
- * An adapter for ViewPagers that will handle adding and removing Controllers
- */
-@Deprecated
-public abstract class ControllerPagerAdapter extends PagerAdapter {
-
-    private static final String KEY_SAVED_PAGES = "ControllerPagerAdapter.savedStates";
-    private static final String KEY_SAVES_STATE = "ControllerPagerAdapter.savesState";
-    private static final String KEY_VISIBLE_PAGE_IDS_KEYS = "ControllerPagerAdapter.visiblePageIds.keys";
-    private static final String KEY_VISIBLE_PAGE_IDS_VALUES = "ControllerPagerAdapter.visiblePageIds.values";
-
-    private final Controller host;
-    private boolean savesState;
-    private SparseArray<Bundle> savedPages = new SparseArray<>();
-    private SparseArray<String> visiblePageIds = new SparseArray<>();
-
-    /**
-     * Creates a new ControllerPagerAdapter using the passed host.
-     */
-    public ControllerPagerAdapter(@NonNull Controller host, boolean saveControllerState) {
-        this.host = host;
-        savesState = saveControllerState;
-    }
-
-    /**
-     * Return the Controller associated with a specified position.
-     */
-    @NonNull
-    public abstract Controller getItem(int position);
-
-    @Override
-    public Object instantiateItem(ViewGroup container, int position) {
-        final String name = makeControllerName(container.getId(), getItemId(position));
-
-        Router router = host.getChildRouter(container, name);
-        if (savesState && !router.hasRootController()) {
-            Bundle routerSavedState = savedPages.get(position);
-
-            if (routerSavedState != null) {
-                router.restoreInstanceState(routerSavedState);
-            }
-        }
-
-        final Controller controller;
-        if (!router.hasRootController()) {
-            controller = getItem(position);
-            router.setRoot(RouterTransaction.with(controller).tag(name));
-        } else {
-            router.rebindIfNeeded();
-            controller = router.getControllerWithTag(name);
-        }
-
-        if (controller != null) {
-            visiblePageIds.put(position, controller.getInstanceId());
-        }
-
-        return router.getControllerWithTag(name);
-    }
-
-    @Override
-    public void destroyItem(ViewGroup container, int position, Object object) {
-        Router router = ((Controller)object).getRouter();
-
-        if (savesState) {
-            Bundle savedState = new Bundle();
-            router.saveInstanceState(savedState);
-            savedPages.put(position, savedState);
-        }
-
-        visiblePageIds.remove(position);
-
-        host.removeChildRouter(router);
-    }
-
-    @Override
-    public boolean isViewFromObject(View view, Object object) {
-        return ((Controller)object).getView() == view;
-    }
-
-    @Override
-    public Parcelable saveState() {
-        Bundle bundle = new Bundle();
-        bundle.putBoolean(KEY_SAVES_STATE, savesState);
-        bundle.putSparseParcelableArray(KEY_SAVED_PAGES, savedPages);
-
-        int[] visiblePageIdsKeys = new int[visiblePageIds.size()];
-        String[] visiblePageIdsValues = new String[visiblePageIds.size()];
-        for (int i = 0; i < visiblePageIds.size(); i++) {
-            visiblePageIdsKeys[i] = visiblePageIds.keyAt(i);
-            visiblePageIdsValues[i] = visiblePageIds.valueAt(i);
-        }
-        bundle.putIntArray(KEY_VISIBLE_PAGE_IDS_KEYS, visiblePageIdsKeys);
-        bundle.putStringArray(KEY_VISIBLE_PAGE_IDS_VALUES, visiblePageIdsValues);
-
-        return bundle;
-    }
-
-    @Override
-    public void restoreState(Parcelable state, ClassLoader loader) {
-        Bundle bundle = (Bundle)state;
-        if (state != null) {
-            savesState = bundle.getBoolean(KEY_SAVES_STATE, false);
-            savedPages = bundle.getSparseParcelableArray(KEY_SAVED_PAGES);
-
-            int[] visiblePageIdsKeys = bundle.getIntArray(KEY_VISIBLE_PAGE_IDS_KEYS);
-            String[] visiblePageIdsValues = bundle.getStringArray(KEY_VISIBLE_PAGE_IDS_VALUES);
-            visiblePageIds = new SparseArray<>(visiblePageIdsKeys.length);
-            for (int i = 0; i < visiblePageIdsKeys.length; i++) {
-                visiblePageIds.put(visiblePageIdsKeys[i], visiblePageIdsValues[i]);
-            }
-        }
-    }
-
-    /**
-     * Returns the already instantiated Controller in the specified position or {@code null} if
-     * this position does not yet have a controller.
-     */
-    @Nullable
-    public Controller getController(int position) {
-        String instanceId = visiblePageIds.get(position);
-        if (instanceId != null) {
-            return host.getRouter().getControllerWithInstanceId(instanceId);
-        } else {
-            return null;
-        }
-    }
-
-    public long getItemId(int position) {
-        return position;
-    }
-
-    private static String makeControllerName(int viewId, long id) {
-        return viewId + ":" + id;
-    }
-
-}

conductor/build.gradle

@@ -3,7 +3,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'de.mobilej.unmock:UnMockPlugin:0.3.6'
+        classpath 'de.mobilej.unmock:UnMockPlugin:0.6.5'
     }
 }
 
@@ -12,7 +12,6 @@ apply plugin: 'de.mobilej.unmock'
 
 android {
     compileSdkVersion rootProject.ext.compileSdkVersion
-    buildToolsVersion rootProject.ext.buildToolsVersion
 
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_7
@@ -33,22 +32,14 @@ configurations {
 }
 
 dependencies {
-    testCompile rootProject.ext.junit
-    testCompile rootProject.ext.roboelectric
+    testImplementation rootProject.ext.junit
+    testImplementation rootProject.ext.roboelectric
 
-    compile rootProject.ext.supportAnnotations
+    api rootProject.ext.androidxAnnotations
 
     lintChecks project(path: ':conductor-lint', configuration: 'lintChecks')
 }
 
-unMock {
-    downloadFrom 'https://oss.sonatype.org/content/groups/public/org/robolectric/android-all/4.3_r2-robolectric-0/android-all-4.3_r2-robolectric-0.jar'
-
-    keep "android.os.Bundle"
-    keep "android.os.BaseBundle"
-    keep "android.text.TextUtils"
-}
-
 task copyLintJar(type: Copy) {
     from(configurations.lintChecks) {
         rename { 'lint.jar' }

conductor/proguard-rules.txt

@@ -2,4 +2,7 @@
 -keepclassmembers public class * extends com.bluelinelabs.conductor.Controller {
    public <init>();
    public <init>(android.os.Bundle);
-}
+}
+-keepclassmembers public class * extends com.bluelinelabs.conductor.ControllerChangeHandler {
+   public <init>();
+}

conductor/src/main/AndroidManifest.xml

@@ -1,3 +1,3 @@
 <manifest package="com.bluelinelabs.conductor">
     <application />
-</manifest>
+</manifest>

conductor/src/main/java/com/bluelinelabs/conductor/ActivityHostedRouter.java

@@ -5,8 +5,8 @@ import android.content.Intent;
 import android.content.IntentSender;
 import android.content.IntentSender.SendIntentException;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.view.ViewGroup;
 
 import com.bluelinelabs.conductor.ControllerChangeHandler.ControllerChangeListener;
@@ -32,6 +32,8 @@ public class ActivityHostedRouter extends Router {
 
             this.lifecycleHandler = lifecycleHandler;
             this.container = container;
+
+            watchContainerAttach();
         }
     }
 
@@ -123,8 +125,14 @@ public class ActivityHostedRouter extends Router {
         return this;
     }
 
-    @Override @Nullable
+    @Override @NonNull
     TransactionIndexer getTransactionIndexer() {
         return transactionIndexer;
     }
+
+    @Override
+    public void onContextAvailable() {
+        super.onContextAvailable();
+    }
+
 }

conductor/src/main/java/com/bluelinelabs/conductor/Backstack.java

@@ -1,8 +1,8 @@
 package com.bluelinelabs.conductor;
 
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 
 import java.util.ArrayDeque;
 import java.util.ArrayList;
@@ -67,10 +67,6 @@ class Backstack implements Iterable<RouterTransaction> {
         return backstack.peek();
     }
 
-    void remove(@NonNull RouterTransaction transaction) {
-        backstack.removeFirstOccurrence(transaction);
-    }
-
     void push(@NonNull RouterTransaction transaction) {
         backstack.push(transaction);
     }
@@ -85,28 +81,19 @@ class Backstack implements Iterable<RouterTransaction> {
     }
 
     void setBackstack(@NonNull List<RouterTransaction> backstack) {
-        for (RouterTransaction existingTransaction : this.backstack) {
-            boolean contains = false;
-            for (RouterTransaction newTransaction : backstack) {
-                if (existingTransaction.controller == newTransaction.controller) {
-                    contains = true;
-                    break;
-                }
-            }
-
-            if (!contains) {
-                existingTransaction.controller.destroy();
-            }
-        }
-
         this.backstack.clear();
         for (RouterTransaction transaction : backstack) {
             this.backstack.push(transaction);
         }
     }
 
-    boolean contains(@NonNull RouterTransaction transaction) {
-        return backstack.contains(transaction);
+    boolean contains(@NonNull Controller controller) {
+        for (RouterTransaction transaction : backstack) {
+            if (controller == transaction.controller) {
+                return true;
+            }
+        }
+        return false;
     }
 
     void saveInstanceState(@NonNull Bundle outState) {

conductor/src/main/java/com/bluelinelabs/conductor/ChangeHandlerFrameLayout.java

@@ -3,8 +3,8 @@ package com.bluelinelabs.conductor;
 import android.annotation.TargetApi;
 import android.content.Context;
 import android.os.Build;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.util.AttributeSet;
 import android.view.MotionEvent;
 import android.view.ViewGroup;

conductor/src/main/java/com/bluelinelabs/conductor/Conductor.java

@@ -2,9 +2,9 @@ package com.bluelinelabs.conductor;
 
 import android.app.Activity;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
-import android.support.annotation.UiThread;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.annotation.UiThread;
 import android.view.ViewGroup;
 
 import com.bluelinelabs.conductor.internal.LifecycleHandler;

conductor/src/main/java/com/bluelinelabs/conductor/Controller.java

@@ -8,11 +8,7 @@ import android.content.IntentSender;
 import android.content.res.Resources;
 import android.os.Build;
 import android.os.Bundle;
-import android.os.Handler;
 import android.os.Parcelable;
-import android.support.annotation.IdRes;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
 import android.text.TextUtils;
 import android.util.SparseArray;
 import android.view.LayoutInflater;
@@ -36,6 +32,10 @@ import java.util.Comparator;
 import java.util.List;
 import java.util.UUID;
 
+import androidx.annotation.IdRes;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
 /**
  * A Controller manages portions of the UI. It is similar to an Activity or Fragment in that it manages its
  * own lifecycle and controls interactions between the UI and whatever logic is required. It is, however,
@@ -63,22 +63,23 @@ public abstract class Controller {
 
     Bundle viewState;
     private Bundle savedInstanceState;
-    private boolean isBeingDestroyed;
+    boolean isBeingDestroyed;
     private boolean destroyed;
     private boolean attached;
     private boolean hasOptionsMenu;
     private boolean optionsMenuHidden;
-    private boolean viewIsAttached;
-    private boolean viewWasDetached;
-    private Router router;
-    private View view;
+    boolean viewIsAttached;
+    boolean viewWasDetached;
+    Router router;
+    View view;
     private Controller parentController;
-    private String instanceId;
+    String instanceId;
     private String targetInstanceId;
     private boolean needsAttach;
     private boolean attachedToUnownedParent;
+    private boolean awaitingParentAttach;
     private boolean hasSavedViewState;
-    private boolean isDetachFrozen;
+    boolean isDetachFrozen;
     private ControllerChangeHandler overriddenPushHandler;
     private ControllerChangeHandler overriddenPopHandler;
     private RetainViewMode retainViewMode = RetainViewMode.RELEASE_DETACH;
@@ -87,9 +88,9 @@ public abstract class Controller {
     private final List<LifecycleListener> lifecycleListeners = new ArrayList<>();
     private final ArrayList<String> requestedPermissions = new ArrayList<>();
     private final ArrayList<RouterRequiringFunc> onRouterSetListeners = new ArrayList<>();
-    private final Handler handler = new Handler();
     private WeakReference<View> destroyedView;
     private boolean isPerformingExitTransition;
+    private boolean isContextAvailable;
 
     @NonNull
     static Controller newInstance(@NonNull Bundle bundle) {
@@ -99,17 +100,23 @@ public abstract class Controller {
         Constructor[] constructors = cls.getConstructors();
         Constructor bundleConstructor = getBundleConstructor(constructors);
 
+        Bundle args = bundle.getBundle(KEY_ARGS);
+        if (args != null) {
+            args.setClassLoader(cls.getClassLoader());
+        }
+
         Controller controller;
         try {
             if (bundleConstructor != null) {
-                Bundle args = bundle.getBundle(KEY_ARGS);
-                if (args != null) {
-                    args.setClassLoader(cls.getClassLoader());
-                }
                 controller = (Controller)bundleConstructor.newInstance(args);
             } else {
                 //noinspection ConstantConditions
                 controller = (Controller)getDefaultConstructor(constructors).newInstance();
+
+                // Restore the args that existed before the last process death
+                if (args != null) {
+                    controller.args.putAll(args);
+                }
             }
         } catch (Exception e) {
             throw new RuntimeException("An exception occurred while creating a new instance of " + className + ". " + e.getMessage(), e);
@@ -347,10 +354,8 @@ public abstract class Controller {
      */
     @NonNull
     public final List<Router> getChildRouters() {
-        List<Router> routers = new ArrayList<>();
-        for (Router router : childRouters) {
-            routers.add(router);
-        }
+        List<Router> routers = new ArrayList<>(childRouters.size());
+        routers.addAll(childRouters);
         return routers;
     }
 
@@ -407,6 +412,19 @@ public abstract class Controller {
      */
     protected void onChangeEnded(@NonNull ControllerChangeHandler changeHandler, @NonNull ControllerChangeType changeType) { }
 
+    /**
+     * Called when this Controller has a Context available to it. This will happen very early on in the lifecycle
+     * (before a view is created). If the host activity is re-created (ex: for orientation change), this will be
+     * called again when the new context is available.
+     */
+    protected void onContextAvailable(@NonNull Context context) { }
+
+    /**
+     * Called when this Controller's Context is no longer available. This can happen when the Controller is
+     * destroyed or when the host Activity is destroyed.
+     */
+    protected void onContextUnavailable() { }
+
     /**
      * Called when this Controller is attached to its host ViewGroup
      *
@@ -558,7 +576,7 @@ public abstract class Controller {
      * @param permission A permission this Controller has requested
      */
     public boolean shouldShowRequestPermissionRationale(@NonNull String permission) {
-        return false;
+        return Build.VERSION.SDK_INT >= 23 && getActivity().shouldShowRequestPermissionRationale(permission);
     }
 
     /**
@@ -733,8 +751,8 @@ public abstract class Controller {
         return false;
     }
 
-    final void setNeedsAttach() {
-        needsAttach = true;
+    final void setNeedsAttach(boolean needsAttach) {
+        this.needsAttach = needsAttach;
     }
 
     final void prepareForHostDetach() {
@@ -773,6 +791,29 @@ public abstract class Controller {
         }
     }
 
+    final void onContextAvailable() {
+        final Context context = router.getActivity();
+
+        if (context != null && !isContextAvailable) {
+            List<LifecycleListener> listeners = new ArrayList<>(lifecycleListeners);
+            for (LifecycleListener lifecycleListener : listeners) {
+                lifecycleListener.preContextAvailable(this);
+            }
+
+            isContextAvailable = true;
+            onContextAvailable(context);
+
+            listeners = new ArrayList<>(lifecycleListeners);
+            for (LifecycleListener lifecycleListener : listeners) {
+                lifecycleListener.postContextAvailable(this, context);
+            }
+        }
+
+        for (Router childRouter : childRouters) {
+            childRouter.onContextAvailable();
+        }
+    }
+
     final void executeWithRouter(@NonNull RouterRequiringFunc listener) {
         if (router != null) {
             listener.execute();
@@ -805,26 +846,55 @@ public abstract class Controller {
     }
 
     final void activityStopped(@NonNull Activity activity) {
+        final boolean attached = this.attached;
+
         if (viewAttachHandler != null) {
             viewAttachHandler.onActivityStopped();
         }
+
+        if (attached && activity.isChangingConfigurations()) {
+            needsAttach = true;
+        }
+
         onActivityStopped(activity);
     }
 
-    final void activityDestroyed(boolean isChangingConfigurations) {
-        if (isChangingConfigurations) {
+    final void activityDestroyed(@NonNull Activity activity) {
+        if (activity.isChangingConfigurations()) {
             detach(view, true, false);
         } else {
             destroy(true);
         }
+
+        if (isContextAvailable) {
+            List<LifecycleListener> listeners = new ArrayList<>(lifecycleListeners);
+            for (LifecycleListener lifecycleListener : listeners) {
+                lifecycleListener.preContextUnavailable(this, activity);
+            }
+
+            isContextAvailable = false;
+            onContextUnavailable();
+
+            listeners = new ArrayList<>(lifecycleListeners);
+            for (LifecycleListener lifecycleListener : listeners) {
+                lifecycleListener.postContextUnavailable(this);
+            }
+        }
     }
 
-    private void attach(@NonNull final View view) {
+    void attach(@NonNull View view) {
         attachedToUnownedParent = router == null || view.getParent() != router.container;
-        if (attachedToUnownedParent) {
+        if (attachedToUnownedParent || isBeingDestroyed) {
             return;
         }
 
+        if (parentController != null && !parentController.attached) {
+            awaitingParentAttach = true;
+            return;
+        } else {
+            awaitingParentAttach = false;
+        }
+
         hasSavedViewState = false;
 
         List<LifecycleListener> listeners = new ArrayList<>(lifecycleListeners);
@@ -833,25 +903,26 @@ public abstract class Controller {
         }
 
         attached = true;
-        needsAttach = false;
+        needsAttach = router.isActivityStopped;
 
-        // This must be posted in a handler to ensure the system can finish attaching views if needed. Otherwise
-        // we can get NPEs when developers decide to immediately pop this controller from onAttach.
-        handler.post(new Runnable() {
-            @Override
-            public void run() {
-                onAttach(view);
+        onAttach(view);
 
-                if (hasOptionsMenu && !optionsMenuHidden) {
-                    router.invalidateOptionsMenu();
-                }
+        if (hasOptionsMenu && !optionsMenuHidden) {
+            router.invalidateOptionsMenu();
+        }
 
-                List<LifecycleListener> listeners = new ArrayList<>(lifecycleListeners);
-                for (LifecycleListener lifecycleListener : listeners) {
-                    lifecycleListener.postAttach(Controller.this, view);
+        listeners = new ArrayList<>(lifecycleListeners);
+        for (LifecycleListener lifecycleListener : listeners) {
+            lifecycleListener.postAttach(Controller.this, view);
+        }
+
+        for (ControllerHostedRouter childRouter : childRouters) {
+            for (RouterTransaction childTransaction : childRouter.backstack) {
+                if (childTransaction.controller.awaitingParentAttach) {
+                    childTransaction.controller.attach(childTransaction.controller.view);
                 }
             }
-        });
+        }
     }
 
     void detach(@NonNull View view, boolean forceViewRefRemoval, boolean blockViewRefRemoval) {
@@ -870,7 +941,10 @@ public abstract class Controller {
             }
 
             attached = false;
-            onDetach(view);
+
+            if (!awaitingParentAttach) {
+                onDetach(view);
+            }
 
             if (hasOptionsMenu && !optionsMenuHidden) {
                 router.invalidateOptionsMenu();
@@ -995,6 +1069,21 @@ public abstract class Controller {
     }
 
     private void performDestroy() {
+        if (isContextAvailable) {
+            List<LifecycleListener> listeners = new ArrayList<>(lifecycleListeners);
+            for (LifecycleListener lifecycleListener : listeners) {
+                lifecycleListener.preContextUnavailable(this, getActivity());
+            }
+
+            isContextAvailable = false;
+            onContextUnavailable();
+
+            listeners = new ArrayList<>(lifecycleListeners);
+            for (LifecycleListener lifecycleListener : listeners) {
+                lifecycleListener.postContextUnavailable(this);
+            }
+        }
+
         if (!destroyed) {
             List<LifecycleListener> listeners = new ArrayList<>(lifecycleListeners);
             for (LifecycleListener lifecycleListener : listeners) {
@@ -1093,7 +1182,7 @@ public abstract class Controller {
             outState.putBundle(KEY_OVERRIDDEN_POP_HANDLER, overriddenPopHandler.toBundle());
         }
 
-        ArrayList<Bundle> childBundles = new ArrayList<>();
+        ArrayList<Bundle> childBundles = new ArrayList<>(childRouters.size());
         for (ControllerHostedRouter childRouter : childRouters) {
             Bundle routerBundle = new Bundle();
             childRouter.saveInstanceState(routerBundle);
@@ -1193,6 +1282,8 @@ public abstract class Controller {
             }
             destroyedView = null;
         }
+
+        changeHandler.onEnd();
     }
 
     final void setDetachFrozen(boolean frozen) {
@@ -1285,6 +1376,12 @@ public abstract class Controller {
         public void preDestroy(@NonNull Controller controller) { }
         public void postDestroy(@NonNull Controller controller) { }
 
+        public void preContextAvailable(@NonNull Controller controller) { }
+        public void postContextAvailable(@NonNull Controller controller, @NonNull Context context) { }
+
+        public void preContextUnavailable(@NonNull Controller controller, @NonNull Context context) { }
+        public void postContextUnavailable(@NonNull Controller controller) { }
+
         public void onSaveInstanceState(@NonNull Controller controller, @NonNull Bundle outState) { }
         public void onRestoreInstanceState(@NonNull Controller controller, @NonNull Bundle savedInstanceState) { }
 

conductor/src/main/java/com/bluelinelabs/conductor/ControllerChangeHandler.java

@@ -1,8 +1,8 @@
 package com.bluelinelabs.conductor;
 
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewParent;
@@ -24,9 +24,9 @@ public abstract class ControllerChangeHandler {
     private static final String KEY_CLASS_NAME = "ControllerChangeHandler.className";
     private static final String KEY_SAVED_STATE = "ControllerChangeHandler.savedState";
 
-    private static final Map<String, ControllerChangeHandler> inProgressPushHandlers = new HashMap<>();
+    static final Map<String, ChangeHandlerData> inProgressChangeHandlers = new HashMap<>();
 
-    private boolean forceRemoveViewOnPush;
+    boolean forceRemoveViewOnPush;
     private boolean hasBeenUsed;
 
     /**
@@ -127,29 +127,34 @@ public abstract class ControllerChangeHandler {
         }
     }
 
-    static boolean completePushImmediately(@NonNull String controllerInstanceId) {
-        ControllerChangeHandler changeHandler = inProgressPushHandlers.get(controllerInstanceId);
-        if (changeHandler != null) {
-            changeHandler.completeImmediately();
-            inProgressPushHandlers.remove(controllerInstanceId);
+    static boolean completeHandlerImmediately(@NonNull String controllerInstanceId) {
+        ChangeHandlerData changeHandlerData = inProgressChangeHandlers.get(controllerInstanceId);
+        if (changeHandlerData != null) {
+            changeHandlerData.changeHandler.completeImmediately();
+            inProgressChangeHandlers.remove(controllerInstanceId);
             return true;
         }
         return false;
     }
 
-    static void abortPush(@NonNull Controller toAbort, @Nullable Controller newController, @NonNull ControllerChangeHandler newChangeHandler) {
-        ControllerChangeHandler handlerForPush = inProgressPushHandlers.get(toAbort.getInstanceId());
-        if (handlerForPush != null) {
-            handlerForPush.onAbortPush(newChangeHandler, newController);
-            inProgressPushHandlers.remove(toAbort.getInstanceId());
+    static void abortOrComplete(@NonNull Controller toAbort, @Nullable Controller newController, @NonNull ControllerChangeHandler newChangeHandler) {
+        ChangeHandlerData changeHandlerData = inProgressChangeHandlers.get(toAbort.getInstanceId());
+        if (changeHandlerData != null) {
+            if (changeHandlerData.isPush) {
+                changeHandlerData.changeHandler.onAbortPush(newChangeHandler, newController);
+            } else {
+                changeHandlerData.changeHandler.completeImmediately();
+            }
+
+            inProgressChangeHandlers.remove(toAbort.getInstanceId());
         }
     }
 
-    static void executeChange(@Nullable final Controller to, @Nullable final Controller from, final boolean isPush, @Nullable final ViewGroup container, @Nullable final ControllerChangeHandler inHandler, @NonNull final List<ControllerChangeListener> listeners) {
-        if (isPush && to != null && to.isDestroyed()) {
-            throw new IllegalStateException("Trying to push a controller that has already been destroyed. (" + to.getClass().getSimpleName() + ")");
-        }
+    static void executeChange(@NonNull final ChangeTransaction transaction) {
+        executeChange(transaction.to, transaction.from, transaction.isPush, transaction.container, transaction.changeHandler, transaction.listeners);
+    }
 
+    private static void executeChange(@Nullable final Controller to, @Nullable final Controller from, final boolean isPush, @Nullable final ViewGroup container, @Nullable final ControllerChangeHandler inHandler, @NonNull final List<ControllerChangeListener> listeners) {
         if (container != null) {
             final ControllerChangeHandler handler;
             if (inHandler == null) {
@@ -161,14 +166,16 @@ public abstract class ControllerChangeHandler {
             }
             handler.hasBeenUsed = true;
 
-            if (isPush && to != null) {
-                inProgressPushHandlers.put(to.getInstanceId(), handler);
-
-                if (from != null) {
-                    completePushImmediately(from.getInstanceId());
+            if (from != null) {
+                if (isPush) {
+                    completeHandlerImmediately(from.getInstanceId());
+                } else {
+                    abortOrComplete(from, to, handler);
                 }
-            } else if (!isPush && from != null) {
-                abortPush(from, to, handler);
+            }
+
+            if (to != null) {
+                inProgressChangeHandlers.put(to.getInstanceId(), new ChangeHandlerData(handler, isPush));
             }
 
             for (ControllerChangeListener listener : listeners) {
@@ -202,7 +209,7 @@ public abstract class ControllerChangeHandler {
                     }
 
                     if (to != null) {
-                        inProgressPushHandlers.remove(to.getInstanceId());
+                        inProgressChangeHandlers.remove(to.getInstanceId());
                         to.changeEnded(handler, toChangeType);
                     }
 
@@ -216,11 +223,17 @@ public abstract class ControllerChangeHandler {
                             ((ViewGroup)fromParent).removeView(fromView);
                         }
                     }
+
+                    if (handler.removesFromViewOnPush() && from != null) {
+                        from.setNeedsAttach(false);
+                    }
                 }
             });
         }
     }
 
+    protected void onEnd(){ }
+
     public boolean removesFromViewOnPush() {
         return true;
     }
@@ -229,6 +242,24 @@ public abstract class ControllerChangeHandler {
         forceRemoveViewOnPush = force;
     }
 
+    static class ChangeTransaction {
+        @Nullable final Controller to;
+        @Nullable final Controller from;
+        final boolean isPush;
+        @Nullable final ViewGroup container;
+        @Nullable final ControllerChangeHandler changeHandler;
+        @NonNull final List<ControllerChangeListener> listeners;
+
+        public ChangeTransaction(@Nullable Controller to, @Nullable Controller from, boolean isPush, @Nullable ViewGroup container, @Nullable ControllerChangeHandler changeHandler, @NonNull List<ControllerChangeListener> listeners) {
+            this.to = to;
+            this.from = from;
+            this.isPush = isPush;
+            this.container = container;
+            this.changeHandler = changeHandler;
+            this.listeners = listeners;
+        }
+    }
+
     /**
      * A listener interface useful for allowing external classes to be notified of change events.
      */
@@ -267,4 +298,14 @@ public abstract class ControllerChangeHandler {
         void onChangeCompleted();
     }
 
+    private static class ChangeHandlerData {
+        public final ControllerChangeHandler changeHandler;
+        public final boolean isPush;
+
+        public ChangeHandlerData(ControllerChangeHandler changeHandler, boolean isPush) {
+            this.changeHandler = changeHandler;
+            this.isPush = isPush;
+        }
+    }
+
 }

conductor/src/main/java/com/bluelinelabs/conductor/ControllerHostedRouter.java

@@ -5,9 +5,9 @@ import android.content.Intent;
 import android.content.IntentSender;
 import android.content.IntentSender.SendIntentException;
 import android.os.Bundle;
-import android.support.annotation.IdRes;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.IdRes;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.view.ViewGroup;
 
 import com.bluelinelabs.conductor.ControllerChangeHandler.ControllerChangeListener;
@@ -15,6 +15,7 @@ import com.bluelinelabs.conductor.internal.TransactionIndexer;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 
 class ControllerHostedRouter extends Router {
 
@@ -44,6 +45,12 @@ class ControllerHostedRouter extends Router {
 
             hostController = controller;
             this.container = container;
+
+            for (RouterTransaction transaction : backstack) {
+                transaction.controller.setParentController(controller);
+            }
+
+            watchContainerAttach();
         }
     }
 
@@ -198,8 +205,8 @@ class ControllerHostedRouter extends Router {
 
     @Override
     void setControllerRouter(@NonNull Controller controller) {
-        super.setControllerRouter(controller);
         controller.setParentController(hostController);
+        super.setControllerRouter(controller);
     }
 
     int getHostId() {
@@ -228,8 +235,21 @@ class ControllerHostedRouter extends Router {
         }
     }
 
-    @Override @Nullable
+    @Override @NonNull
     TransactionIndexer getTransactionIndexer() {
-        return getRootRouter().getTransactionIndexer();
+        Router rootRouter = getRootRouter();
+        if (rootRouter == this) {
+            String debugInfo;
+            if (hostController != null) {
+                debugInfo = String.format(Locale.ENGLISH, "%s (attached? %b, destroyed? %b, parent: %s)",
+                        hostController.getClass().getSimpleName(), hostController.isAttached(), hostController.isBeingDestroyed, hostController.getParentController());
+            } else {
+                debugInfo = "null host controller";
+            }
+            throw new IllegalStateException("Unable to retrieve TransactionIndexer from " + debugInfo);
+        } else {
+            return getRootRouter().getTransactionIndexer();
+        }
     }
+
 }

conductor/src/main/java/com/bluelinelabs/conductor/RestoreViewOnCreateController.java

@@ -1,8 +1,8 @@
 package com.bluelinelabs.conductor;
 
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;

conductor/src/main/java/com/bluelinelabs/conductor/Router.java

@@ -4,9 +4,6 @@ import android.app.Activity;
 import android.content.Intent;
 import android.content.IntentSender;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
-import android.support.annotation.UiThread;
 import android.view.Menu;
 import android.view.MenuInflater;
 import android.view.MenuItem;
@@ -14,6 +11,7 @@ import android.view.View;
 import android.view.ViewGroup;
 
 import com.bluelinelabs.conductor.Controller.LifecycleListener;
+import com.bluelinelabs.conductor.ControllerChangeHandler.ChangeTransaction;
 import com.bluelinelabs.conductor.ControllerChangeHandler.ControllerChangeListener;
 import com.bluelinelabs.conductor.changehandler.SimpleSwapChangeHandler;
 import com.bluelinelabs.conductor.internal.NoOpControllerChangeHandler;
@@ -25,6 +23,10 @@ import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.annotation.UiThread;
+
 /**
  * A Router implements navigation and backstack handling for {@link Controller}s. Router objects are attached
  * to Activity/containing ViewGroup pairs. Routers do not directly render or push Views to the container ViewGroup,
@@ -35,11 +37,14 @@ public abstract class Router {
     private static final String KEY_BACKSTACK = "Router.backstack";
     private static final String KEY_POPS_LAST_VIEW = "Router.popsLastView";
 
-    protected final Backstack backstack = new Backstack();
+    final Backstack backstack = new Backstack();
     private final List<ControllerChangeListener> changeListeners = new ArrayList<>();
+    private final List<ChangeTransaction> pendingControllerChanges = new ArrayList<>();
     final List<Controller> destroyingControllers = new ArrayList<>();
 
     private boolean popsLastView = false;
+    boolean containerFullyAttached = false;
+    boolean isActivityStopped = false;
 
     ViewGroup container;
 
@@ -134,15 +139,20 @@ public abstract class Router {
         } else {
             RouterTransaction removedTransaction = null;
             RouterTransaction nextTransaction = null;
-            for (RouterTransaction transaction : backstack) {
+            Iterator<RouterTransaction> iterator = backstack.iterator();
+            ControllerChangeHandler topPushHandler = topTransaction != null ? topTransaction.pushChangeHandler() : null;
+            final boolean needsNextTransactionAttach = topPushHandler != null ? !topPushHandler.removesFromViewOnPush() : false;
+
+            while (iterator.hasNext()) {
+                RouterTransaction transaction = iterator.next();
                 if (transaction.controller == controller) {
                     if (controller.isAttached()) {
                         trackDestroyingController(transaction);
                     }
-                    backstack.remove(transaction);
+                    iterator.remove();
                     removedTransaction = transaction;
                 } else if (removedTransaction != null) {
-                    if (!transaction.controller.isAttached()) {
+                    if (needsNextTransactionAttach && !transaction.controller.isAttached()) {
                         nextTransaction = transaction;
                     }
                     break;
@@ -376,7 +386,7 @@ public abstract class Router {
      */
     @NonNull
     public List<RouterTransaction> getBackstack() {
-        List<RouterTransaction> list = new ArrayList<>();
+        List<RouterTransaction> list = new ArrayList<>(backstack.size());
         Iterator<RouterTransaction> backstackIterator = backstack.reverseIterator();
         while (backstackIterator.hasNext()) {
             list.add(backstackIterator.next());
@@ -396,29 +406,58 @@ public abstract class Router {
     public void setBackstack(@NonNull List<RouterTransaction> newBackstack, @Nullable ControllerChangeHandler changeHandler) {
         ThreadUtils.ensureMainThread();
 
+        List<RouterTransaction> oldTransactions = getBackstack();
         List<RouterTransaction> oldVisibleTransactions = getVisibleTransactions(backstack.iterator());
 
-        boolean newRootRequiresPush = !(newBackstack.size() > 0 && backstack.contains(newBackstack.get(0)));
-
         removeAllExceptVisibleAndUnowned();
         ensureOrderedTransactionIndices(newBackstack);
+        ensureNoDuplicateControllers(newBackstack);
 
         backstack.setBackstack(newBackstack);
-        for (RouterTransaction transaction : backstack) {
+
+        List<RouterTransaction> transactionsToBeRemoved = new ArrayList<>();
+        for (RouterTransaction oldTransaction : oldTransactions) {
+            boolean contains = false;
+            for (RouterTransaction newTransaction : newBackstack) {
+                if (oldTransaction.controller == newTransaction.controller) {
+                    contains = true;
+                    break;
+                }
+            }
+
+            if (!contains) {
+                // Inform the controller that it will be destroyed soon
+                oldTransaction.controller.isBeingDestroyed = true;
+                transactionsToBeRemoved.add(oldTransaction);
+            }
+        }
+
+        // Ensure all new controllers have a valid router set
+        Iterator<RouterTransaction> backstackIterator = backstack.reverseIterator();
+        while (backstackIterator.hasNext()) {
+            RouterTransaction transaction = backstackIterator.next();
             transaction.onAttachedToRouter();
+            setControllerRouter(transaction.controller);
         }
 
         if (newBackstack.size() > 0) {
             List<RouterTransaction> reverseNewBackstack = new ArrayList<>(newBackstack);
             Collections.reverse(reverseNewBackstack);
             List<RouterTransaction> newVisibleTransactions = getVisibleTransactions(reverseNewBackstack.iterator());
+            boolean newRootRequiresPush = !(newVisibleTransactions.size() > 0 && oldTransactions.contains(newVisibleTransactions.get(0)));
 
             boolean visibleTransactionsChanged = !backstacksAreEqual(newVisibleTransactions, oldVisibleTransactions);
             if (visibleTransactionsChanged) {
-                RouterTransaction rootTransaction = oldVisibleTransactions.size() > 0 ? oldVisibleTransactions.get(0) : null;
+                RouterTransaction oldRootTransaction = oldVisibleTransactions.size() > 0 ? oldVisibleTransactions.get(0) : null;
+                RouterTransaction newRootTransaction = newVisibleTransactions.get(0);
+
                 // Replace the old root with the new one
-                if (rootTransaction == null || rootTransaction.controller != newVisibleTransactions.get(0).controller) {
-                    performControllerChange(newVisibleTransactions.get(0), rootTransaction, newRootRequiresPush, changeHandler);
+                if (oldRootTransaction == null || oldRootTransaction.controller != newRootTransaction.controller) {
+                    // Ensure the existing root controller is fully pushed to the view hierarchy
+                    if (oldRootTransaction != null) {
+                        ControllerChangeHandler.completeHandlerImmediately(oldRootTransaction.controller.getInstanceId());
+                    }
+                    performControllerChange(newRootTransaction, oldRootTransaction, newRootRequiresPush, changeHandler);
                 }
 
                 // Remove all visible controllers that were previously on the backstack
@@ -427,6 +466,7 @@ public abstract class Router {
                     if (!newVisibleTransactions.contains(transaction)) {
                         ControllerChangeHandler localHandler = changeHandler != null ? changeHandler.copy() : new SimpleSwapChangeHandler();
                         localHandler.setForceRemoveViewOnPush(true);
+                        ControllerChangeHandler.completeHandlerImmediately(transaction.controller.getInstanceId());
                         performControllerChange(null, transaction, newRootRequiresPush, localHandler);
                     }
                 }
@@ -440,9 +480,31 @@ public abstract class Router {
                 }
             }
 
-            // Ensure all new controllers have a valid router set
-            for (RouterTransaction transaction : newBackstack) {
-                transaction.controller.setRouter(this);
+        } else {
+            // Remove all visible controllers that were previously on the backstack
+            for (int i = oldVisibleTransactions.size() - 1; i >= 0; i--) {
+                RouterTransaction transaction = oldVisibleTransactions.get(i);
+                ControllerChangeHandler localHandler = changeHandler != null ? changeHandler.copy() : new SimpleSwapChangeHandler();
+                ControllerChangeHandler.completeHandlerImmediately(transaction.controller.getInstanceId());
+                performControllerChange(null, transaction, false, localHandler);
+            }
+        }
+
+        // Destroy all old controllers that are no longer on the backstack. We don't do this when we initially
+        // set the backstack to prevent the possibility that they'll be destroyed before the controller
+        // change handler runs.
+        for (RouterTransaction removedTransaction : transactionsToBeRemoved) {
+
+            // Still need to ensure the controller isn't queued up to be removed later on.
+            boolean willBeRemoved = false;
+            for (ChangeTransaction pendingTransaction : pendingControllerChanges) {
+                if (pendingTransaction.from == removedTransaction.controller) {
+                    willBeRemoved = true;
+                }
+            }
+
+            if (!willBeRemoved) {
+                removedTransaction.controller.destroy();
             }
         }
     }
@@ -489,6 +551,8 @@ public abstract class Router {
 
             if (transaction.controller.getNeedsAttach()) {
                 performControllerChange(transaction, null, true, new SimpleSwapChangeHandler(false));
+            } else {
+                setControllerRouter(transaction.controller);
             }
         }
     }
@@ -501,6 +565,8 @@ public abstract class Router {
     }
 
     public final void onActivityStarted(@NonNull Activity activity) {
+        isActivityStopped = false;
+
         for (RouterTransaction transaction : backstack) {
             transaction.controller.activityStarted(activity);
 
@@ -538,6 +604,8 @@ public abstract class Router {
                 childRouter.onActivityStopped(activity);
             }
         }
+
+        isActivityStopped = true;
     }
 
     public void onActivityDestroyed(@NonNull Activity activity) {
@@ -545,7 +613,7 @@ public abstract class Router {
         changeListeners.clear();
 
         for (RouterTransaction transaction : backstack) {
-            transaction.controller.activityDestroyed(activity.isChangingConfigurations());
+            transaction.controller.activityDestroyed(activity);
 
             for (Router childRouter : transaction.controller.getChildRouters()) {
                 childRouter.onActivityDestroyed(activity);
@@ -554,7 +622,7 @@ public abstract class Router {
 
         for (int index = destroyingControllers.size() - 1; index >= 0; index--) {
             Controller controller = destroyingControllers.get(index);
-            controller.activityDestroyed(activity.isChangingConfigurations());
+            controller.activityDestroyed(activity);
 
             for (Router childRouter : controller.getChildRouters()) {
                 childRouter.onActivityDestroyed(activity);
@@ -564,18 +632,16 @@ public abstract class Router {
         container = null;
     }
 
-    void prepareForHostDetach() {
+    public void prepareForHostDetach() {
         for (RouterTransaction transaction : backstack) {
-            if (ControllerChangeHandler.completePushImmediately(transaction.controller.getInstanceId())) {
-                transaction.controller.setNeedsAttach();
+            if (ControllerChangeHandler.completeHandlerImmediately(transaction.controller.getInstanceId())) {
+                transaction.controller.setNeedsAttach(true);
             }
             transaction.controller.prepareForHostDetach();
         }
     }
 
     public void saveInstanceState(@NonNull Bundle outState) {
-        prepareForHostDetach();
-
         Bundle backstackState = new Bundle();
         backstack.saveInstanceState(backstackState);
 
@@ -653,15 +719,32 @@ public abstract class Router {
         }
     }
 
+    void watchContainerAttach() {
+        container.post(new Runnable() {
+            @Override
+            public void run() {
+                containerFullyAttached = true;
+            }
+        });
+    }
+
     void prepareForContainerRemoval() {
+        containerFullyAttached = false;
+
         if (container != null) {
             container.setOnHierarchyChangeListener(null);
         }
     }
 
+    void onContextAvailable() {
+        for (RouterTransaction transaction : backstack) {
+            transaction.controller.onContextAvailable();
+        }
+    }
+
     @NonNull
     final List<Controller> getControllers() {
-        List<Controller> controllers = new ArrayList<>();
+        List<Controller> controllers = new ArrayList<>(backstack.size());
 
         Iterator<RouterTransaction> backstackIterator = backstack.reverseIterator();
         while (backstackIterator.hasNext()) {
@@ -699,23 +782,68 @@ public abstract class Router {
         performControllerChange(to, from, isPush, changeHandler);
     }
 
-    private void performControllerChange(@Nullable final RouterTransaction to, @Nullable final RouterTransaction from, boolean isPush, @Nullable ControllerChangeHandler changeHandler) {
+    void performControllerChange(@Nullable RouterTransaction to, @Nullable RouterTransaction from, boolean isPush, @Nullable ControllerChangeHandler changeHandler) {
         Controller toController = to != null ? to.controller : null;
         Controller fromController = from != null ? from.controller : null;
+        boolean forceDetachDestroy = false;
 
         if (to != null) {
             to.ensureValidIndex(getTransactionIndexer());
             setControllerRouter(toController);
         } else if (backstack.size() == 0 && !popsLastView) {
-            // We're emptying out the backstack. Views get weird if you transition them out, so just no-op it. The hosting
-            // Activity should be handling this by finishing or at least hiding this view.
+            // We're emptying out the backstack. Views get weird if you transition them out, so just no-op it. The host
+            // Activity or controller should be handling this by finishing or at least hiding this view.
             changeHandler = new NoOpControllerChangeHandler();
+            forceDetachDestroy = true;
         }
 
-        ControllerChangeHandler.executeChange(toController, fromController, isPush, container, changeHandler, changeListeners);
+        performControllerChange(toController, fromController, isPush, changeHandler);
+
+        if (forceDetachDestroy && fromController != null && fromController.getView() != null) {
+            fromController.detach(fromController.getView(), true, false);
+        }
+    }
+
+    private void performControllerChange(@Nullable final Controller to, @Nullable final Controller from, final boolean isPush, @Nullable final ControllerChangeHandler changeHandler) {
+        if (isPush && to != null && to.isDestroyed()) {
+            throw new IllegalStateException("Trying to push a controller that has already been destroyed. (" + to.getClass().getSimpleName() + ")");
+        }
+
+        final ChangeTransaction transaction = new ChangeTransaction(to, from, isPush, container, changeHandler, new ArrayList<>(changeListeners));
+
+        if (pendingControllerChanges.size() > 0) {
+            // If we already have changes queued up (awaiting full container attach), queue this one up as well so they don't happen
+            // out of order.
+            pendingControllerChanges.add(transaction);
+        } else if (from != null && (changeHandler == null || changeHandler.removesFromViewOnPush()) && !containerFullyAttached) {
+            // If the change handler will remove the from view, we have to make sure the container is fully attached first so we avoid NPEs
+            // within ViewGroup (details on issue #287). Post this to the container to ensure the attach is complete before we try to remove
+            // anything.
+            pendingControllerChanges.add(transaction);
+            container.post(new Runnable() {
+                @Override
+                public void run() {
+                    performPendingControllerChanges();
+                }
+            });
+        } else {
+            ControllerChangeHandler.executeChange(transaction);
+        }
+    }
+
+    void performPendingControllerChanges() {
+        // We're intentionally using dynamic size checking (list.size()) here so we can account for changes
+        // that occur during this loop (ex: if a controller is popped from within onAttach)
+        for (int i = 0; i < pendingControllerChanges.size(); i++) {
+            ControllerChangeHandler.executeChange(pendingControllerChanges.get(i));
+        }
+        pendingControllerChanges.clear();
     }
 
     protected void pushToBackstack(@NonNull RouterTransaction entry) {
+        if (backstack.contains(entry.controller)) {
+            throw new IllegalStateException("Trying to push a controller that already exists on the backstack.");
+        }
         backstack.push(entry);
     }
 
@@ -754,7 +882,7 @@ public abstract class Router {
         }
 
         final int childCount = container.getChildCount();
-        for (int i = 0; i < childCount; i++) {
+        for (int i = childCount - 1; i >= 0; i--) {
             final View child = container.getChildAt(i);
             if (!views.contains(child)) {
                 container.removeView(child);
@@ -762,10 +890,10 @@ public abstract class Router {
         }
     }
 
-    // Swap around transaction indicies to ensure they don't get thrown out of order by the
+    // Swap around transaction indices to ensure they don't get thrown out of order by the
     // developer rearranging the backstack at runtime.
     private void ensureOrderedTransactionIndices(List<RouterTransaction> backstack) {
-        List<Integer> indices = new ArrayList<>();
+        List<Integer> indices = new ArrayList<>(backstack.size());
         for (RouterTransaction transaction : backstack) {
             transaction.ensureValidIndex(getTransactionIndexer());
             indices.add(transaction.transactionIndex);
@@ -778,6 +906,17 @@ public abstract class Router {
         }
     }
 
+    private void ensureNoDuplicateControllers(List<RouterTransaction> backstack) {
+        for (int i = 0; i < backstack.size(); i++) {
+            Controller controller = backstack.get(i).controller;
+            for (int j = i + 1; j < backstack.size(); j++) {
+                if (backstack.get(j).controller == controller) {
+                    throw new IllegalStateException("Trying to push the same controller to the backstack more than once.");
+                }
+            }
+        }
+    }
+
     private void addRouterViewsToList(@NonNull Router router, @NonNull List<View> list) {
         for (Controller controller : router.getControllers()) {
             if (controller.getView() != null) {
@@ -822,6 +961,7 @@ public abstract class Router {
 
     void setControllerRouter(@NonNull Controller controller) {
         controller.setRouter(this);
+        controller.onContextAvailable();
     }
 
     abstract void invalidateOptionsMenu();
@@ -836,6 +976,6 @@ public abstract class Router {
     abstract boolean hasHost();
     @NonNull abstract List<Router> getSiblingRouters();
     @NonNull abstract Router getRootRouter();
-    @Nullable abstract TransactionIndexer getTransactionIndexer();
+    @NonNull abstract TransactionIndexer getTransactionIndexer();
 
 }

conductor/src/main/java/com/bluelinelabs/conductor/RouterTransaction.java

@@ -1,8 +1,8 @@
 package com.bluelinelabs.conductor;
 
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 
 import com.bluelinelabs.conductor.internal.TransactionIndexer;
 
@@ -108,11 +108,8 @@ public class RouterTransaction {
         }
     }
 
-    void ensureValidIndex(@Nullable TransactionIndexer indexer) {
-        if (indexer == null) {
-            throw new RuntimeException();
-        }
-        if (transactionIndex == INVALID_INDEX && indexer != null) {
+    void ensureValidIndex(@NonNull TransactionIndexer indexer) {
+        if (transactionIndex == INVALID_INDEX) {
             transactionIndex = indexer.nextIndex();
         }
     }
@@ -140,4 +137,4 @@ public class RouterTransaction {
         return bundle;
     }
 
-}
+}

conductor/src/main/java/com/bluelinelabs/conductor/changehandler/AnimatorChangeHandler.java

@@ -4,8 +4,8 @@ import android.animation.Animator;
 import android.animation.Animator.AnimatorListener;
 import android.animation.AnimatorListenerAdapter;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewTreeObserver;
@@ -21,23 +21,28 @@ public abstract class AnimatorChangeHandler extends ControllerChangeHandler {
     private static final String KEY_DURATION = "AnimatorChangeHandler.duration";
     private static final String KEY_REMOVES_FROM_ON_PUSH = "AnimatorChangeHandler.removesFromViewOnPush";
 
+    @SuppressWarnings("WeakerAccess")
     public static final long DEFAULT_ANIMATION_DURATION = -1;
 
     private long animationDuration;
-    private boolean removesFromViewOnPush;
-    private boolean canceled;
-    private boolean needsImmediateCompletion;
+    boolean removesFromViewOnPush;
+    boolean canceled;
+    boolean needsImmediateCompletion;
     private boolean completed;
-    private Animator animator;
+    Animator animator;
+    private OnAnimationReadyOrAbortedListener onAnimationReadyOrAbortedListener;
 
+    @SuppressWarnings("WeakerAccess")
     public AnimatorChangeHandler() {
         this(DEFAULT_ANIMATION_DURATION, true);
     }
 
+    @SuppressWarnings("WeakerAccess")
     public AnimatorChangeHandler(boolean removesFromViewOnPush) {
         this(DEFAULT_ANIMATION_DURATION, removesFromViewOnPush);
     }
 
+    @SuppressWarnings("WeakerAccess")
     public AnimatorChangeHandler(long duration) {
         this(duration, true);
     }
@@ -68,6 +73,8 @@ public abstract class AnimatorChangeHandler extends ControllerChangeHandler {
         canceled = true;
         if (animator != null) {
             animator.cancel();
+        } else if (onAnimationReadyOrAbortedListener != null) {
+            onAnimationReadyOrAbortedListener.onReadyOrAborted();
         }
     }
 
@@ -78,6 +85,8 @@ public abstract class AnimatorChangeHandler extends ControllerChangeHandler {
         needsImmediateCompletion = true;
         if (animator != null) {
             animator.end();
+        } else if (onAnimationReadyOrAbortedListener != null) {
+            onAnimationReadyOrAbortedListener.onReadyOrAborted();
         }
     }
 
@@ -121,24 +130,8 @@ public abstract class AnimatorChangeHandler extends ControllerChangeHandler {
 
             if (to.getWidth() <= 0 && to.getHeight() <= 0) {
                 readyToAnimate = false;
-                to.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
-                    boolean hasRun;
-
-                    @Override
-                    public boolean onPreDraw() {
-                        final ViewTreeObserver observer = to.getViewTreeObserver();
-                        if (observer.isAlive()) {
-                            observer.removeOnPreDrawListener(this);
-                        }
-
-                        // Apparently this gets called multiple times, even if removeOnPreDrawListener is called successfully.
-                        if (!hasRun) {
-                            hasRun = true;
-                            performAnimation(container, from, to, isPush, addingToView, changeListener);
-                        }
-                        return true;
-                    }
-                });
+                onAnimationReadyOrAbortedListener = new OnAnimationReadyOrAbortedListener(container, from, to, isPush, true, changeListener);
+                to.getViewTreeObserver().addOnPreDrawListener(onAnimationReadyOrAbortedListener);
             }
         }
 
@@ -147,7 +140,7 @@ public abstract class AnimatorChangeHandler extends ControllerChangeHandler {
         }
     }
 
-    private void complete(@NonNull ControllerChangeCompletedListener changeListener, @Nullable AnimatorListener animatorListener) {
+    void complete(@NonNull ControllerChangeCompletedListener changeListener, @Nullable AnimatorListener animatorListener) {
         if (!completed) {
             completed = true;
             changeListener.onChangeCompleted();
@@ -160,9 +153,11 @@ public abstract class AnimatorChangeHandler extends ControllerChangeHandler {
             animator.cancel();
             animator = null;
         }
+
+        onAnimationReadyOrAbortedListener = null;
     }
 
-    private void performAnimation(@NonNull final ViewGroup container, @Nullable final View from, @Nullable final View to, final boolean isPush, final boolean toAddedToContainer, @NonNull final ControllerChangeCompletedListener changeListener) {
+    void performAnimation(@NonNull final ViewGroup container, @Nullable final View from, @Nullable final View to, final boolean isPush, final boolean toAddedToContainer, @NonNull final ControllerChangeCompletedListener changeListener) {
         if (canceled) {
             complete(changeListener, null);
             return;
@@ -187,8 +182,12 @@ public abstract class AnimatorChangeHandler extends ControllerChangeHandler {
         animator.addListener(new AnimatorListenerAdapter() {
             @Override
             public void onAnimationCancel(Animator animation) {
-                if (from != null && (!isPush || removesFromViewOnPush) && needsImmediateCompletion) {
-                    container.removeView(from);
+                if (from != null) {
+                    resetFromView(from);
+                }
+
+                if (to != null && to.getParent() == container) {
+                    container.removeView(to);
                 }
 
                 complete(changeListener, this);
@@ -213,4 +212,46 @@ public abstract class AnimatorChangeHandler extends ControllerChangeHandler {
         animator.start();
     }
 
+    private class OnAnimationReadyOrAbortedListener implements ViewTreeObserver.OnPreDrawListener {
+        @NonNull final ViewGroup container;
+        @Nullable final View from;
+        @Nullable final View to;
+        final boolean isPush;
+        final boolean addingToView;
+        @NonNull final ControllerChangeCompletedListener changeListener;
+        private boolean hasRun;
+
+        OnAnimationReadyOrAbortedListener(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush, boolean addingToView, @NonNull ControllerChangeCompletedListener changeListener) {
+            this.container = container;
+            this.from = from;
+            this.to = to;
+            this.isPush = isPush;
+            this.addingToView = addingToView;
+            this.changeListener = changeListener;
+        }
+
+        @Override
+        public boolean onPreDraw() {
+            onReadyOrAborted();
+
+            return true;
+        }
+
+        void onReadyOrAborted() {
+            if (!hasRun) {
+                hasRun = true;
+
+                if (to != null) {
+                    final ViewTreeObserver observer = to.getViewTreeObserver();
+                    if (observer.isAlive()) {
+                        observer.removeOnPreDrawListener(this);
+                    }
+                }
+
+                performAnimation(container, from, to, isPush, addingToView, changeListener);
+            }
+        }
+
+    }
+
 }

conductor/src/main/java/com/bluelinelabs/conductor/changehandler/AutoTransitionChangeHandler.java

@@ -1,30 +0,0 @@
-package com.bluelinelabs.conductor.changehandler;
-
-import android.annotation.TargetApi;
-import android.os.Build;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
-import android.transition.AutoTransition;
-import android.transition.Transition;
-import android.view.View;
-import android.view.ViewGroup;
-
-import com.bluelinelabs.conductor.ControllerChangeHandler;
-
-/**
- * A change handler that will use an AutoTransition.
- */
-@TargetApi(Build.VERSION_CODES.LOLLIPOP)
-public class AutoTransitionChangeHandler extends TransitionChangeHandler {
-
-    @Override @NonNull
-    protected Transition getTransition(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush) {
-        return new AutoTransition();
-    }
-
-    @Override @NonNull
-    public ControllerChangeHandler copy() {
-        return new AutoTransitionChangeHandler();
-    }
-
-}

conductor/src/main/java/com/bluelinelabs/conductor/changehandler/FadeChangeHandler.java

@@ -3,8 +3,8 @@ package com.bluelinelabs.conductor.changehandler;
 import android.animation.Animator;
 import android.animation.AnimatorSet;
 import android.animation.ObjectAnimator;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.view.View;
 import android.view.ViewGroup;
 
@@ -37,7 +37,7 @@ public class FadeChangeHandler extends AnimatorChangeHandler {
             animator.play(ObjectAnimator.ofFloat(to, View.ALPHA, start, 1));
         }
 
-        if (from != null && removesFromViewOnPush()) {
+        if (from != null && (!isPush || removesFromViewOnPush())) {
             animator.play(ObjectAnimator.ofFloat(from, View.ALPHA, 0));
         }
 

conductor/src/main/java/com/bluelinelabs/conductor/changehandler/HorizontalChangeHandler.java

@@ -3,8 +3,8 @@ package com.bluelinelabs.conductor.changehandler;
 import android.animation.Animator;
 import android.animation.AnimatorSet;
 import android.animation.ObjectAnimator;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.view.View;
 import android.view.ViewGroup;
 

conductor/src/main/java/com/bluelinelabs/conductor/changehandler/SharedElementTransitionChangeHandler.java

@@ -0,0 +1,658 @@
+package com.bluelinelabs.conductor.changehandler;
+
+import android.annotation.TargetApi;
+import android.app.SharedElementCallback;
+import android.graphics.Rect;
+import android.os.Build;
+import android.transition.Transition;
+import android.transition.Transition.TransitionListener;
+import android.transition.TransitionSet;
+import android.util.ArrayMap;
+import android.view.View;
+import android.view.ViewGroup;
+import android.view.ViewTreeObserver;
+import android.view.ViewTreeObserver.OnPreDrawListener;
+
+import com.bluelinelabs.conductor.Controller;
+import com.bluelinelabs.conductor.ControllerChangeHandler;
+import com.bluelinelabs.conductor.internal.LegacyTransitionUtils;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+/**
+ * A TransitionChangeHandler that facilitates using different Transitions for the entering view, the exiting view,
+ * and shared elements between the two.
+ *
+ * @deprecated See {@link TransitionChangeHandler}
+ */
+// Much of this class is based on FragmentTransition.java and FragmentTransitionCompat21.java from the Android support library
+@TargetApi(Build.VERSION_CODES.LOLLIPOP)
+@Deprecated
+public abstract class SharedElementTransitionChangeHandler extends TransitionChangeHandler {
+
+    // A map of from -> to names. Generally these will be the same.
+    @NonNull  final ArrayMap<String, String> sharedElementNames = new ArrayMap<>();
+
+    @NonNull  final List<String> waitForTransitionNames = new ArrayList<>();
+    @NonNull  final List<ViewParentPair> removedViews = new ArrayList<>();
+
+    @Nullable Transition exitTransition;
+    @Nullable Transition enterTransition;
+    @Nullable Transition sharedElementTransition;
+    @Nullable private SharedElementCallback exitTransitionCallback;
+    @Nullable private SharedElementCallback enterTransitionCallback;
+
+    @NonNull
+    @Override
+    protected final Transition getTransition(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush) {
+        exitTransition = getExitTransition(container, from, to, isPush);
+        enterTransition = getEnterTransition(container, from, to, isPush);
+        sharedElementTransition = getSharedElementTransition(container, from, to, isPush);
+        exitTransitionCallback = getExitTransitionCallback(container, from, to, isPush);
+        enterTransitionCallback = getEnterTransitionCallback(container, from, to, isPush);
+
+        if (enterTransition == null && sharedElementTransition == null && exitTransition == null) {
+            throw new IllegalStateException("SharedElementTransitionChangeHandler must have at least one transaction.");
+        }
+
+        return mergeTransitions(isPush);
+    }
+
+    @Override
+    public void prepareForTransition(@NonNull final ViewGroup container, @Nullable final View from, @Nullable final View to, @NonNull final Transition transition, final boolean isPush, @NonNull final OnTransitionPreparedListener onTransitionPreparedListener) {
+        OnTransitionPreparedListener listener = new OnTransitionPreparedListener() {
+            @Override
+            public void onPrepared() {
+                configureTransition(container, from, to, transition, isPush);
+                onTransitionPreparedListener.onPrepared();
+            }
+        };
+
+        configureSharedElements(container, from, to, isPush);
+
+        if (to != null && to.getParent() == null && waitForTransitionNames.size() > 0) {
+            waitOnAllTransitionNames(to, listener);
+            container.addView(to);
+        } else {
+            listener.onPrepared();
+        }
+    }
+
+    @Override
+    public final void executePropertyChanges(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, @Nullable Transition transition, boolean isPush) {
+        if (to != null && removedViews.size() > 0) {
+            to.setVisibility(View.VISIBLE);
+
+            for (ViewParentPair removedView : removedViews) {
+                removedView.parent.addView(removedView.view);
+            }
+
+            removedViews.clear();
+        }
+
+        super.executePropertyChanges(container, from, to, transition, isPush);
+    }
+
+    @Override
+    public void onAbortPush(@NonNull ControllerChangeHandler newHandler, @Nullable Controller newTop) {
+        super.onAbortPush(newHandler, newTop);
+
+        removedViews.clear();
+    }
+
+    void configureTransition(@NonNull final ViewGroup container, @Nullable View from, @Nullable View to, @NonNull final Transition transition, boolean isPush) {
+        final View nonExistentView = new View(container.getContext());
+
+        List<View> fromSharedElements = new ArrayList<>();
+        List<View> toSharedElements = new ArrayList<>();
+
+        configureSharedElements(container, nonExistentView, to, from, isPush, fromSharedElements, toSharedElements);
+
+        List<View> exitingViews = exitTransition != null ? configureEnteringExitingViews(exitTransition, from, fromSharedElements, nonExistentView) : null;
+        if (exitingViews == null || exitingViews.isEmpty()) {
+            exitTransition = null;
+        }
+
+        if (enterTransition != null) {
+            enterTransition.addTarget(nonExistentView);
+        }
+
+        final List<View> enteringViews = new ArrayList<>();
+        scheduleRemoveTargets(transition, enterTransition, enteringViews, exitTransition, exitingViews, sharedElementTransition, toSharedElements);
+        scheduleTargetChange(container, to, nonExistentView, toSharedElements, enteringViews, exitingViews);
+
+        setNameOverrides(container, toSharedElements);
+        scheduleNameReset(container, toSharedElements);
+    }
+
+    private void waitOnAllTransitionNames(@NonNull final View to, @NonNull final OnTransitionPreparedListener onTransitionPreparedListener) {
+        OnPreDrawListener onPreDrawListener = new OnPreDrawListener() {
+            boolean addedSubviewListeners;
+
+            @Override
+            public boolean onPreDraw() {
+                List<View> foundViews = new ArrayList<>();
+                boolean allViewsFound = true;
+                for (String transitionName : waitForTransitionNames) {
+                    View namedView = LegacyTransitionUtils.findNamedView(to, transitionName);
+                    if (namedView != null) {
+                        foundViews.add(LegacyTransitionUtils.findNamedView(to, transitionName));
+                    } else {
+                        allViewsFound = false;
+                        break;
+                    }
+                }
+
+                if (allViewsFound && !addedSubviewListeners) {
+                    addedSubviewListeners = true;
+                    waitOnChildTransitionNames(to, foundViews, this, onTransitionPreparedListener);
+                }
+
+                return false;
+            }
+        };
+
+        to.getViewTreeObserver().addOnPreDrawListener(onPreDrawListener);
+    }
+
+    void waitOnChildTransitionNames(@NonNull final View to, @NonNull List<View> foundViews, @NonNull final OnPreDrawListener parentPreDrawListener, @NonNull final OnTransitionPreparedListener onTransitionPreparedListener) {
+        for (final View view : foundViews) {
+            OneShotPreDrawListener.add(true, view, new Runnable() {
+                @Override
+                public void run() {
+                    waitForTransitionNames.remove(view.getTransitionName());
+
+                    removedViews.add(new ViewParentPair(view, (ViewGroup)view.getParent()));
+                    ((ViewGroup)view.getParent()).removeView(view);
+
+                    if (waitForTransitionNames.size() == 0) {
+                        to.getViewTreeObserver().removeOnPreDrawListener(parentPreDrawListener);
+                        to.setVisibility(View.INVISIBLE);
+                        onTransitionPreparedListener.onPrepared();
+                    }
+                }
+            });
+        }
+    }
+
+    private void scheduleTargetChange(@NonNull final ViewGroup container, @Nullable final View to, @NonNull final View nonExistentView,
+                                      @NonNull final List<View> toSharedElements, @NonNull final List<View> enteringViews, @Nullable final List<View> exitingViews) {
+        OneShotPreDrawListener.add(true, container, new Runnable() {
+            @Override
+            public void run() {
+                if (enterTransition != null) {
+                    enterTransition.removeTarget(nonExistentView);
+                    List<View> views = configureEnteringExitingViews(enterTransition, to, toSharedElements, nonExistentView);
+                    enteringViews.addAll(views);
+                }
+
+                if (exitingViews != null) {
+                    if (exitTransition != null) {
+                        List<View> tempExiting = new ArrayList<>();
+                        tempExiting.add(nonExistentView);
+                        LegacyTransitionUtils.replaceTargets(exitTransition, exitingViews, tempExiting);
+                    }
+                    exitingViews.clear();
+                    exitingViews.add(nonExistentView);
+                }
+            }
+        });
+    }
+
+    private Transition mergeTransitions(boolean isPush) {
+        boolean overlap = enterTransition == null || exitTransition == null || allowTransitionOverlap(isPush);
+
+        if (overlap) {
+            return LegacyTransitionUtils.mergeTransitions(TransitionSet.ORDERING_TOGETHER, exitTransition, enterTransition, sharedElementTransition);
+        } else {
+            Transition staggered = LegacyTransitionUtils.mergeTransitions(TransitionSet.ORDERING_SEQUENTIAL, exitTransition, enterTransition);
+            return LegacyTransitionUtils.mergeTransitions(TransitionSet.ORDERING_TOGETHER, staggered, sharedElementTransition);
+        }
+    }
+
+    @NonNull List<View> configureEnteringExitingViews(@NonNull Transition transition, @Nullable View view, @NonNull List<View> sharedElements, @NonNull View nonExistentView) {
+        List<View> viewList = new ArrayList<>();
+        if (view != null) {
+            captureTransitioningViews(viewList, view);
+        }
+        viewList.removeAll(sharedElements);
+        if (!viewList.isEmpty()) {
+            viewList.add(nonExistentView);
+            LegacyTransitionUtils.addTargets(transition, viewList);
+        }
+        return viewList;
+    }
+
+    private void configureSharedElements(@NonNull ViewGroup container, @NonNull final View nonExistentView, @Nullable final View to, @Nullable View from,
+                                         final boolean isPush, @NonNull final List<View> fromSharedElements, @NonNull final List<View> toSharedElements) {
+
+        if (to == null || from == null) {
+            return;
+        }
+
+        ArrayMap<String, View> capturedFromSharedElements = captureFromSharedElements(from);
+
+        if (sharedElementNames.isEmpty()) {
+            sharedElementTransition = null;
+        } else if (capturedFromSharedElements != null) {
+            fromSharedElements.addAll(capturedFromSharedElements.values());
+        }
+
+        if (enterTransition == null && exitTransition == null && sharedElementTransition == null) {
+            return;
+        }
+
+        callSharedElementStartEnd(capturedFromSharedElements, true);
+
+        final Rect toEpicenter;
+        if (sharedElementTransition != null) {
+            toEpicenter = new Rect();
+            LegacyTransitionUtils.setTargets(sharedElementTransition, nonExistentView, fromSharedElements);
+            setFromEpicenter(capturedFromSharedElements);
+            if (enterTransition != null) {
+                enterTransition.setEpicenterCallback(new Transition.EpicenterCallback() {
+                    @Override
+                    public Rect onGetEpicenter(Transition transition) {
+                        if (toEpicenter.isEmpty()) {
+                            return null;
+                        }
+                        return toEpicenter;
+                    }
+                });
+            }
+        } else {
+            toEpicenter = null;
+        }
+
+        OneShotPreDrawListener.add(true, container, new Runnable() {
+            @Override
+            public void run() {
+                ArrayMap<String, View> capturedToSharedElements = captureToSharedElements(to, isPush);
+
+                if (capturedToSharedElements != null) {
+                    toSharedElements.addAll(capturedToSharedElements.values());
+                    toSharedElements.add(nonExistentView);
+                }
+
+                callSharedElementStartEnd(capturedToSharedElements, false);
+                if (sharedElementTransition != null) {
+                    sharedElementTransition.getTargets().clear();
+                    sharedElementTransition.getTargets().addAll(toSharedElements);
+                    LegacyTransitionUtils.replaceTargets(sharedElementTransition, fromSharedElements, toSharedElements);
+
+                    final View toEpicenterView = getToEpicenterView(capturedToSharedElements);
+                    if (toEpicenterView != null && toEpicenter != null) {
+                        LegacyTransitionUtils.getBoundsOnScreen(toEpicenterView, toEpicenter);
+                    }
+                }
+            }
+        });
+    }
+
+    @Nullable View getToEpicenterView(@Nullable ArrayMap<String, View> toSharedElements) {
+        if (enterTransition != null && sharedElementNames.size() > 0 && toSharedElements != null) {
+            return toSharedElements.get(sharedElementNames.valueAt(0));
+        }
+        return null;
+    }
+
+    private void setFromEpicenter(@Nullable ArrayMap<String, View> fromSharedElements) {
+        if (sharedElementNames.size() > 0 && fromSharedElements != null) {
+            final View fromEpicenterView = fromSharedElements.get(sharedElementNames.keyAt(0));
+
+            if (sharedElementTransition != null) {
+                LegacyTransitionUtils.setEpicenter(sharedElementTransition, fromEpicenterView);
+            }
+
+            if (exitTransition != null) {
+                LegacyTransitionUtils.setEpicenter(exitTransition, fromEpicenterView);
+            }
+        }
+    }
+
+    @Nullable ArrayMap<String, View> captureToSharedElements(@Nullable final View to, boolean isPush) {
+        if (sharedElementNames.isEmpty() || sharedElementTransition == null || to == null) {
+            sharedElementNames.clear();
+            return null;
+        }
+
+        final ArrayMap<String, View> toSharedElements = new ArrayMap<>();
+        LegacyTransitionUtils.findNamedViews(toSharedElements, to);
+        for (ViewParentPair removedView : removedViews) {
+            toSharedElements.put(removedView.view.getTransitionName(), removedView.view);
+        }
+
+        final List<String> names = new ArrayList<>(sharedElementNames.values());
+
+        toSharedElements.retainAll(names);
+        if (enterTransitionCallback != null) {
+            enterTransitionCallback.onMapSharedElements(names, toSharedElements);
+            for (int i = names.size() - 1; i >= 0; i--) {
+                String name = names.get(i);
+                View view = toSharedElements.get(name);
+                if (view == null) {
+                    String key = findKeyForValue(sharedElementNames, name);
+                    if (key != null) {
+                        sharedElementNames.remove(key);
+                    }
+                } else if (!name.equals(view.getTransitionName())) {
+                    String key = findKeyForValue(sharedElementNames, name);
+                    if (key != null) {
+                        sharedElementNames.put(key, view.getTransitionName());
+                    }
+                }
+            }
+        } else {
+            for (int i = sharedElementNames.size() - 1; i >= 0; i--) {
+                final String targetName = sharedElementNames.valueAt(i);
+                if (!toSharedElements.containsKey(targetName)) {
+                    sharedElementNames.removeAt(i);
+                }
+            }
+        }
+        return toSharedElements;
+    }
+
+    @Nullable String findKeyForValue(@NonNull ArrayMap<String, String> map, @NonNull String value) {
+        final int numElements = map.size();
+        for (int i = 0; i < numElements; i++) {
+            if (value.equals(map.valueAt(i))) {
+                return map.keyAt(i);
+            }
+        }
+        return null;
+    }
+
+    @Nullable
+    private ArrayMap<String, View> captureFromSharedElements(@NonNull View from) {
+        if (sharedElementNames.isEmpty() || sharedElementTransition == null) {
+            sharedElementNames.clear();
+            return null;
+        }
+
+        final ArrayMap<String, View> fromSharedElements = new ArrayMap<>();
+        LegacyTransitionUtils.findNamedViews(fromSharedElements, from);
+
+        final List<String> names = new ArrayList<>(sharedElementNames.keySet());
+
+        fromSharedElements.retainAll(names);
+        if (exitTransitionCallback != null) {
+            exitTransitionCallback.onMapSharedElements(names, fromSharedElements);
+            for (int i = names.size() - 1; i >= 0; i--) {
+                String name = names.get(i);
+                View view = fromSharedElements.get(name);
+                if (view == null) {
+                    sharedElementNames.remove(name);
+                } else if (!name.equals(view.getTransitionName())) {
+                    String targetValue = sharedElementNames.remove(name);
+                    sharedElementNames.put(view.getTransitionName(), targetValue);
+                }
+            }
+        } else {
+            sharedElementNames.retainAll(fromSharedElements.keySet());
+        }
+        return fromSharedElements;
+    }
+
+    void callSharedElementStartEnd(@Nullable ArrayMap<String, View> sharedElements, boolean isStart) {
+        if (enterTransitionCallback != null) {
+            final int count = sharedElements == null ? 0 : sharedElements.size();
+            List<View> views = new ArrayList<>(count);
+            List<String> names = new ArrayList<>(count);
+            for (int i = 0; i < count; i++) {
+                names.add(sharedElements.keyAt(i));
+                views.add(sharedElements.valueAt(i));
+            }
+            if (isStart) {
+                enterTransitionCallback.onSharedElementStart(names, views, null);
+            } else {
+                enterTransitionCallback.onSharedElementEnd(names, views, null);
+            }
+        }
+    }
+
+    private void captureTransitioningViews(@NonNull List<View> transitioningViews, @NonNull View view) {
+        if (view.getVisibility() == View.VISIBLE) {
+            if (view instanceof ViewGroup) {
+                ViewGroup viewGroup = (ViewGroup) view;
+                if (viewGroup.isTransitionGroup()) {
+                    transitioningViews.add(viewGroup);
+                } else {
+                    int count = viewGroup.getChildCount();
+                    for (int i = 0; i < count; i++) {
+                        View child = viewGroup.getChildAt(i);
+                        captureTransitioningViews(transitioningViews, child);
+                    }
+                }
+            } else {
+                transitioningViews.add(view);
+            }
+        }
+    }
+
+    private void scheduleRemoveTargets(@NonNull final Transition overallTransition,
+                                       @Nullable final Transition enterTransition, @Nullable final List<View> enteringViews,
+                                       @Nullable final Transition exitTransition, @Nullable final List<View> exitingViews,
+                                       @Nullable final Transition sharedElementTransition, @Nullable final List<View> toSharedElements) {
+        overallTransition.addListener(new TransitionListener() {
+            @Override
+            public void onTransitionStart(Transition transition) {
+                if (enterTransition != null && enteringViews != null) {
+                    LegacyTransitionUtils.replaceTargets(enterTransition, enteringViews, null);
+                }
+                if (exitTransition != null && exitingViews != null) {
+                    LegacyTransitionUtils.replaceTargets(exitTransition, exitingViews, null);
+                }
+                if (sharedElementTransition != null && toSharedElements != null) {
+                    LegacyTransitionUtils.replaceTargets(sharedElementTransition, toSharedElements, null);
+                }
+            }
+
+            @Override
+            public void onTransitionEnd(Transition transition) { }
+
+            @Override
+            public void onTransitionCancel(Transition transition) { }
+
+            @Override
+            public void onTransitionPause(Transition transition) { }
+
+            @Override
+            public void onTransitionResume(Transition transition) { }
+        });
+    }
+
+    private void setNameOverrides(@NonNull final View container, @NonNull final List<View> toSharedElements) {
+        OneShotPreDrawListener.add(true, container, new Runnable() {
+            @Override
+            public void run() {
+                final int numSharedElements = toSharedElements.size();
+                for (int i = 0; i < numSharedElements; i++) {
+                    View view = toSharedElements.get(i);
+                    String name = view.getTransitionName();
+                    if (name != null) {
+                        String inName = findKeyForValue(sharedElementNames, name);
+                        view.setTransitionName(inName);
+                    }
+                }
+            }
+        });
+    }
+
+    private void scheduleNameReset(@NonNull final ViewGroup container, @NonNull final List<View> toSharedElements) {
+        OneShotPreDrawListener.add(true, container, new Runnable() {
+            @Override
+            public void run() {
+                final int numSharedElements = toSharedElements.size();
+                for (int i = 0; i < numSharedElements; i++) {
+                    final View view = toSharedElements.get(i);
+                    final String name = view.getTransitionName();
+                    final String inName = sharedElementNames.get(name);
+                    view.setTransitionName(inName);
+                }
+            }
+        });
+    }
+
+    /**
+     * Will be called when views are ready to have their shared elements configured. Within this method one of the addSharedElement methods
+     * should be called for each shared element that will be used. If one or more of these shared elements will not instantly be available in
+     * the incoming view (for ex, in a RecyclerView), waitOnSharedElementNamed can be called to delay the transition until everything is available.
+     */
+    public abstract void configureSharedElements(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush);
+
+    /**
+     * Should return the transition that will be used on the exiting ("from") view, if one is desired.
+     */
+    @Nullable
+    public abstract Transition getExitTransition(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush);
+
+    /**
+     * Should return the transition that will be used on shared elements between the from and to views.
+     */
+    @Nullable
+    public abstract Transition getSharedElementTransition(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush);
+
+    /**
+     * Should return the transition that will be used on the entering ("to") view, if one is desired.
+     */
+    @Nullable
+    public abstract Transition getEnterTransition(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush);
+
+    /**
+     * Should return a callback that can be used to customize transition behavior of the shared element transition for the "from" view.
+     */
+    @Nullable
+    public SharedElementCallback getExitTransitionCallback(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush) {
+        return null;
+    }
+
+    /**
+     * Should return a callback that can be used to customize transition behavior of the shared element transition for the "to" view.
+     */
+    @Nullable
+    public SharedElementCallback getEnterTransitionCallback(@NonNull ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush) {
+        return null;
+    }
+
+    /**
+     * Should return whether or not the the exit transition and enter transition should overlap. If true,
+     * the enter transition will start as soon as possible. Otherwise, the enter transition will wait until the
+     * completion of the exit transition. Defaults to true.
+     */
+    public boolean allowTransitionOverlap(boolean isPush) {
+        return true;
+    }
+
+    /**
+     * Used to register an element that will take part in the shared element transition.
+     *
+     * @param name The transition name that is used for both the entering and exiting views.
+     */
+    protected final void addSharedElement(@NonNull String name) {
+        sharedElementNames.put(name, name);
+    }
+
+    /**
+     * Used to register an element that will take part in the shared element transition. Maps the name used in the
+     * "from" view to the name used in the "to" view if they are not the same.
+     *
+     * @param fromName The transition name used in the "from" view
+     * @param toName The transition name used in the "to" view
+     */
+    protected final void addSharedElement(@NonNull String fromName, @NonNull String toName) {
+        sharedElementNames.put(fromName, toName);
+    }
+
+    /**
+     * Used to register an element that will take part in the shared element transition. Maps the name used in the
+     * "from" view to the name used in the "to" view if they are not the same.
+     *
+     * @param sharedElement The view from the "from" view that will take part in the shared element transition
+     * @param toName The transition name used in the "to" view
+     */
+    protected final void addSharedElement(@NonNull View sharedElement, @NonNull String toName) {
+        String transitionName = sharedElement.getTransitionName();
+        if (transitionName == null) {
+            throw new IllegalArgumentException("Unique transitionNames are required for all sharedElements");
+        }
+        sharedElementNames.put(transitionName, toName);
+    }
+
+    /**
+     * The transition will be delayed until the view with the name passed in is available in the "to" hierarchy. This is
+     * particularly useful for views that don't load instantly, like RecyclerViews. Note that using this method can
+     * potentially lock up your app indefinitely if the view never loads!
+     */
+    protected final void waitOnSharedElementNamed(@NonNull String name) {
+        if (!sharedElementNames.values().contains(name)) {
+            throw new IllegalStateException("Can't wait on a shared element that hasn't been registered using addSharedElement");
+        }
+        waitForTransitionNames.add(name);
+    }
+
+    private static class OneShotPreDrawListener implements OnPreDrawListener, View.OnAttachStateChangeListener {
+
+        private final View view;
+        private ViewTreeObserver viewTreeObserver;
+        private final Runnable runnable;
+        private final boolean preDrawReturnValue;
+
+        private OneShotPreDrawListener(boolean preDrawReturnValue, @NonNull View view, @NonNull Runnable runnable) {
+            this.preDrawReturnValue = preDrawReturnValue;
+            this.view = view;
+            viewTreeObserver = view.getViewTreeObserver();
+            this.runnable = runnable;
+        }
+
+        @NonNull
+        public static OneShotPreDrawListener add(boolean preDrawReturnValue, @NonNull View view, @NonNull Runnable runnable) {
+            OneShotPreDrawListener listener = new OneShotPreDrawListener(preDrawReturnValue, view, runnable);
+            view.getViewTreeObserver().addOnPreDrawListener(listener);
+            view.addOnAttachStateChangeListener(listener);
+            return listener;
+        }
+
+        @Override
+        public boolean onPreDraw() {
+            removeListener();
+            runnable.run();
+            return preDrawReturnValue;
+        }
+
+        private void removeListener() {
+            if (viewTreeObserver.isAlive()) {
+                viewTreeObserver.removeOnPreDrawListener(this);
+            } else {
+                view.getViewTreeObserver().removeOnPreDrawListener(this);
+            }
+            view.removeOnAttachStateChangeListener(this);
+        }
+
+        @Override
+        public void onViewAttachedToWindow(View v) {
+            viewTreeObserver = v.getViewTreeObserver();
+        }
+
+        @Override
+        public void onViewDetachedFromWindow(View v) {
+            removeListener();
+        }
+
+    }
+
+    private static class ViewParentPair {
+        @NonNull final View view;
+        @NonNull final ViewGroup parent;
+
+        ViewParentPair(@NonNull View view, ViewGroup parent) {
+            this.view = view;
+            this.parent = parent;
+        }
+    }
+
+}

conductor/src/main/java/com/bluelinelabs/conductor/changehandler/SimpleSwapChangeHandler.java

@@ -1,8 +1,8 @@
 package com.bluelinelabs.conductor.changehandler;
 
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.view.View;
 import android.view.View.OnAttachStateChangeListener;
 import android.view.ViewGroup;

conductor/src/main/java/com/bluelinelabs/conductor/changehandler/TransitionChangeHandler.java

@@ -2,8 +2,8 @@ package com.bluelinelabs.conductor.changehandler;
 
 import android.annotation.TargetApi;
 import android.os.Build;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.transition.Transition;
 import android.transition.Transition.TransitionListener;
 import android.transition.TransitionManager;
@@ -15,15 +15,22 @@ import com.bluelinelabs.conductor.ControllerChangeHandler;
 
 /**
  * A base {@link ControllerChangeHandler} that facilitates using {@link android.transition.Transition}s to replace Controller Views.
+ *
+ * @deprecated Transitions are backported via
+ * <a href="https://developer.android.com/jetpack/androidx/releases/transition">AndroidX</a>.
+ * They have the same API, but are preferred to the built-in framework transitions as they fix
+ * platform-specific bugs, and even work on versions older than 5.0.
+ * The {@code androidx-transition} module provides an equivalent {@link ControllerChangeHandler}.
  */
 @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+@Deprecated
 public abstract class TransitionChangeHandler extends ControllerChangeHandler {
 
     public interface OnTransitionPreparedListener {
         void onPrepared();
     }
 
-    private boolean canceled;
+    boolean canceled;
     private boolean needsImmediateCompletion;
 
     /**
@@ -51,8 +58,12 @@ public abstract class TransitionChangeHandler extends ControllerChangeHandler {
         needsImmediateCompletion = true;
     }
 
+    @Nullable
+    private ControllerChangeCompletedListener listener;
+
     @Override
     public void performChange(@NonNull final ViewGroup container, @Nullable final View from, @Nullable final View to, final boolean isPush, @NonNull final ControllerChangeCompletedListener changeListener) {
+        listener = changeListener;
         if (canceled) {
             changeListener.onChangeCompleted();
             return;
@@ -63,19 +74,30 @@ public abstract class TransitionChangeHandler extends ControllerChangeHandler {
             return;
         }
 
+        final Runnable onTransitionNotStarted = new Runnable() {
+            @Override
+            public void run() {
+                changeListener.onChangeCompleted();
+            }
+        };
+
         final Transition transition = getTransition(container, from, to, isPush);
         transition.addListener(new TransitionListener() {
             @Override
-            public void onTransitionStart(Transition transition) { }
+            public void onTransitionStart(Transition transition) {
+                container.removeCallbacks(onTransitionNotStarted);
+            }
 
             @Override
             public void onTransitionEnd(Transition transition) {
-                changeListener.onChangeCompleted();
+                listener.onChangeCompleted();
+                listener = null;
             }
 
             @Override
             public void onTransitionCancel(Transition transition) {
-                changeListener.onChangeCompleted();
+                listener.onChangeCompleted();
+                listener = null;
             }
 
             @Override
@@ -91,6 +113,7 @@ public abstract class TransitionChangeHandler extends ControllerChangeHandler {
                 if (!canceled) {
                     TransitionManager.beginDelayedTransition(container, transition);
                     executePropertyChanges(container, from, to, transition, isPush);
+                    container.post(onTransitionNotStarted);
                 }
             }
         });

conductor/src/main/java/com/bluelinelabs/conductor/changehandler/TransitionChangeHandlerCompat.java

@@ -2,8 +2,8 @@ package com.bluelinelabs.conductor.changehandler;
 
 import android.os.Build;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.view.View;
 import android.view.ViewGroup;
 
@@ -20,6 +20,7 @@ public class TransitionChangeHandlerCompat extends ControllerChangeHandler {
     private static final String KEY_CHANGE_HANDLER_CLASS = "TransitionChangeHandlerCompat.changeHandler.class";
     private static final String KEY_HANDLER_STATE = "TransitionChangeHandlerCompat.changeHandler.state";
 
+    @Nullable 
     private ControllerChangeHandler changeHandler;
 
     public TransitionChangeHandlerCompat() { }
@@ -41,17 +42,23 @@ public class TransitionChangeHandlerCompat extends ControllerChangeHandler {
 
     @Override
     public void performChange(@NonNull final ViewGroup container, @Nullable View from, @Nullable View to, boolean isPush, @NonNull final ControllerChangeCompletedListener changeListener) {
-        changeHandler.performChange(container, from, to, isPush, changeListener);
+        if (changeHandler != null) {
+            changeHandler.performChange(container, from, to, isPush, changeListener);
+        }
     }
 
     @Override
     public void saveToBundle(@NonNull Bundle bundle) {
         super.saveToBundle(bundle);
 
-        bundle.putString(KEY_CHANGE_HANDLER_CLASS, changeHandler.getClass().getName());
+        if (changeHandler != null) {
+            bundle.putString(KEY_CHANGE_HANDLER_CLASS, changeHandler.getClass().getName());
+        }
 
         Bundle stateBundle = new Bundle();
-        changeHandler.saveToBundle(stateBundle);
+        if (changeHandler != null) {
+            changeHandler.saveToBundle(stateBundle);
+        }
         bundle.putBundle(KEY_HANDLER_STATE, stateBundle);
     }
 
@@ -67,7 +74,10 @@ public class TransitionChangeHandlerCompat extends ControllerChangeHandler {
 
     @Override
     public boolean removesFromViewOnPush() {
-        return changeHandler.removesFromViewOnPush();
+        if (changeHandler != null) {
+            return changeHandler.removesFromViewOnPush();
+        }
+        return true;
     }
 
     @Override @NonNull
@@ -81,17 +91,27 @@ public class TransitionChangeHandlerCompat extends ControllerChangeHandler {
 
     @Override
     public void onAbortPush(@NonNull ControllerChangeHandler newHandler, @Nullable Controller newTop) {
-        changeHandler.onAbortPush(newHandler, newTop);
+        if (changeHandler != null) {
+            changeHandler.onAbortPush(newHandler, newTop);
+        }
     }
 
     @Override
     public void completeImmediately() {
+      if (changeHandler != null) {
         changeHandler.completeImmediately();
+      }
     }
 
     @Override
     public void setForceRemoveViewOnPush(boolean force) {
+      if (changeHandler != null) {
         changeHandler.setForceRemoveViewOnPush(force);
+      }
     }
 
+    @Override 
+    protected void onEnd() {
+        changeHandler = null;
+    }
 }

conductor/src/main/java/com/bluelinelabs/conductor/changehandler/VerticalChangeHandler.java

@@ -3,8 +3,8 @@ package com.bluelinelabs.conductor.changehandler;
 import android.animation.Animator;
 import android.animation.AnimatorSet;
 import android.animation.ObjectAnimator;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.view.View;
 import android.view.ViewGroup;
 

conductor/src/main/java/com/bluelinelabs/conductor/internal/ClassUtils.java

@@ -1,7 +1,7 @@
 package com.bluelinelabs.conductor.internal;
 
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.text.TextUtils;
 
 public class ClassUtils {

conductor/src/main/java/com/bluelinelabs/conductor/internal/LegacyTransitionUtils.java

@@ -0,0 +1,185 @@
+package com.bluelinelabs.conductor.internal;
+
+import android.annotation.TargetApi;
+import android.graphics.Rect;
+import android.os.Build;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import android.transition.Transition;
+import android.transition.TransitionSet;
+import android.view.View;
+import android.view.ViewGroup;
+
+import java.util.List;
+import java.util.Map;
+
+@TargetApi(Build.VERSION_CODES.LOLLIPOP)
+public class LegacyTransitionUtils {
+
+    public static void findNamedViews(@NonNull Map<String, View> namedViews, View view) {
+        if (view.getVisibility() == View.VISIBLE) {
+            String transitionName = view.getTransitionName();
+            if (transitionName != null) {
+                namedViews.put(transitionName, view);
+            }
+
+            if (view instanceof ViewGroup) {
+                ViewGroup viewGroup = (ViewGroup) view;
+                int childCount = viewGroup.getChildCount();
+                for (int i = 0; i < childCount; i++) {
+                    View child = viewGroup.getChildAt(i);
+                    findNamedViews(namedViews, child);
+                }
+            }
+        }
+    }
+
+    @Nullable
+    public static View findNamedView(@NonNull View view, @NonNull String transitionName) {
+        if (transitionName.equals(view.getTransitionName())) {
+            return view;
+        }
+
+        if (view instanceof ViewGroup) {
+            ViewGroup viewGroup = (ViewGroup) view;
+            int childCount = viewGroup.getChildCount();
+            for (int i = 0; i < childCount; i++) {
+                View viewWithTransitionName = findNamedView(viewGroup.getChildAt(i), transitionName);
+                if (viewWithTransitionName != null) {
+                    return viewWithTransitionName;
+                }
+            }
+        }
+
+        return null;
+    }
+
+    public static void setEpicenter(@NonNull Transition transition, @Nullable View view) {
+        if (view != null) {
+            final Rect epicenter = new Rect();
+            getBoundsOnScreen(view, epicenter);
+            transition.setEpicenterCallback(new Transition.EpicenterCallback() {
+                @Override
+                public Rect onGetEpicenter(Transition transition) {
+                    return epicenter;
+                }
+            });
+        }
+    }
+
+    public static void getBoundsOnScreen(@NonNull View view, @NonNull Rect epicenter) {
+        int[] loc = new int[2];
+        view.getLocationOnScreen(loc);
+        epicenter.set(loc[0], loc[1], loc[0] + view.getWidth(), loc[1] + view.getHeight());
+    }
+
+    public static void setTargets(@NonNull Transition transition, @NonNull View nonExistentView, @NonNull List<View> sharedViews) {
+        final List<View> views = transition.getTargets();
+        views.clear();
+        final int count = sharedViews.size();
+        for (int i = 0; i < count; i++) {
+            final View view = sharedViews.get(i);
+            bfsAddViewChildren(views, view);
+        }
+        views.add(nonExistentView);
+        sharedViews.add(nonExistentView);
+        addTargets(transition, sharedViews);
+    }
+
+    public static void addTargets(@Nullable Transition transition, @NonNull List<View> views) {
+        if (transition == null) {
+            return;
+        }
+        if (transition instanceof TransitionSet) {
+            TransitionSet set = (TransitionSet) transition;
+            int numTransitions = set.getTransitionCount();
+            for (int i = 0; i < numTransitions; i++) {
+                Transition child = set.getTransitionAt(i);
+                addTargets(child, views);
+            }
+        } else if (!hasSimpleTarget(transition)) {
+            List<View> targets = transition.getTargets();
+            if (isNullOrEmpty(targets)) {
+                int numViews = views.size();
+                for (int i = 0; i < numViews; i++) {
+                    transition.addTarget(views.get(i));
+                }
+            }
+        }
+    }
+
+    public static void replaceTargets(@NonNull Transition transition, @NonNull List<View> oldTargets, @Nullable List<View> newTargets) {
+        if (transition instanceof TransitionSet) {
+            TransitionSet set = (TransitionSet) transition;
+            int numTransitions = set.getTransitionCount();
+            for (int i = 0; i < numTransitions; i++) {
+                Transition child = set.getTransitionAt(i);
+                replaceTargets(child, oldTargets, newTargets);
+            }
+        } else if (!LegacyTransitionUtils.hasSimpleTarget(transition)) {
+            List<View> targets = transition.getTargets();
+            if (targets != null && targets.size() == oldTargets.size() && targets.containsAll(oldTargets)) {
+                final int targetCount = newTargets == null ? 0 : newTargets.size();
+                for (int i = 0; i < targetCount; i++) {
+                    transition.addTarget(newTargets.get(i));
+                }
+                for (int i = oldTargets.size() - 1; i >= 0; i--) {
+                    transition.removeTarget(oldTargets.get(i));
+                }
+            }
+        }
+    }
+
+    private static void bfsAddViewChildren(@NonNull final List<View> views, @NonNull final View startView) {
+        final int startIndex = views.size();
+        if (containedBeforeIndex(views, startView, startIndex)) {
+            return; // This child is already in the list, so all its children are also.
+        }
+        views.add(startView);
+        for (int index = startIndex; index < views.size(); index++) {
+            final View view = views.get(index);
+            if (view instanceof ViewGroup) {
+                ViewGroup viewGroup = (ViewGroup) view;
+                final int childCount = viewGroup.getChildCount();
+                for (int childIndex = 0; childIndex < childCount; childIndex++) {
+                    final View child = viewGroup.getChildAt(childIndex);
+                    if (!containedBeforeIndex(views, child, startIndex)) {
+                        views.add(child);
+                    }
+                }
+            }
+        }
+    }
+
+    private static boolean containedBeforeIndex(@NonNull List<View> views, View view, int maxIndex) {
+        for (int i = 0; i < maxIndex; i++) {
+            if (views.get(i) == view) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public static boolean hasSimpleTarget(@NonNull Transition transition) {
+        return !isNullOrEmpty(transition.getTargetIds())
+                || !isNullOrEmpty(transition.getTargetNames())
+                || !isNullOrEmpty(transition.getTargetTypes());
+    }
+
+    private static boolean isNullOrEmpty(@Nullable List list) {
+        return list == null || list.isEmpty();
+    }
+
+    @NonNull
+    public static TransitionSet mergeTransitions(int ordering, Transition... transitions) {
+        TransitionSet transitionSet = new TransitionSet();
+        for (Transition transition : transitions) {
+            if (transition != null) {
+                transitionSet.addTransition(transition);
+            }
+        }
+        transitionSet.setOrdering(ordering);
+        return transitionSet;
+    }
+
+}

conductor/src/main/java/com/bluelinelabs/conductor/internal/LifecycleHandler.java

@@ -11,8 +11,6 @@ import android.os.Build;
 import android.os.Bundle;
 import android.os.Parcel;
 import android.os.Parcelable;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
 import android.util.SparseArray;
 import android.view.Menu;
 import android.view.MenuInflater;
@@ -27,6 +25,9 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
 public class LifecycleHandler extends Fragment implements ActivityLifecycleCallbacks {
 
     private static final String FRAGMENT_TAG = "LifecycleHandler";
@@ -40,7 +41,9 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
     private boolean hasRegisteredCallbacks;
     private boolean destroyed;
     private boolean attached;
+    private boolean hasPreparedForHostDetach;
 
+    private static final Map<Activity, LifecycleHandler> activeLifecycleHandlers = new HashMap<>();
     private SparseArray<String> permissionRequestMap = new SparseArray<>();
     private SparseArray<String> activityRequestMap = new SparseArray<>();
     private ArrayList<PendingPermissionRequest> pendingPermissionRequests = new ArrayList<>();
@@ -54,7 +57,10 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
 
     @Nullable
     private static LifecycleHandler findInActivity(@NonNull Activity activity) {
-        LifecycleHandler lifecycleHandler = (LifecycleHandler)activity.getFragmentManager().findFragmentByTag(FRAGMENT_TAG);
+        LifecycleHandler lifecycleHandler = activeLifecycleHandlers.get(activity);
+        if (lifecycleHandler == null) {
+            lifecycleHandler = (LifecycleHandler)activity.getFragmentManager().findFragmentByTag(FRAGMENT_TAG);
+        }
         if (lifecycleHandler != null) {
             lifecycleHandler.registerActivityListener(activity);
         }
@@ -113,6 +119,11 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
         if (!hasRegisteredCallbacks) {
             hasRegisteredCallbacks = true;
             activity.getApplication().registerActivityLifecycleCallbacks(this);
+
+            // Since Fragment transactions are async, we have to keep an <Activity, LifecycleHandler> map in addition
+            // to trying to find the LifecycleHandler fragment in the Activity to handle the case of the developer
+            // trying to immediately get > 1 router in the same Activity. See issue #299.
+            activeLifecycleHandlers.put(activity, this);
         }
     }
 
@@ -147,6 +158,7 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
 
         if (activity != null) {
             activity.getApplication().unregisterActivityLifecycleCallbacks(this);
+            activeLifecycleHandlers.remove(activity);
             destroyRouters();
             activity = null;
         }
@@ -184,6 +196,10 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
                 requestPermissions(request.instanceId, request.permissions, request.requestCode);
             }
         }
+
+        for (ActivityHostedRouter router : new ArrayList<>(routerMap.values())) {
+            router.onContextAvailable();
+        }
     }
 
     private void destroyRouters() {
@@ -191,7 +207,7 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
             destroyed = true;
 
             if (activity != null) {
-                for (Router router : routerMap.values()) {
+                for (Router router : getRouters()) {
                     router.onActivityDestroyed(activity);
                 }
             }
@@ -204,7 +220,7 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
 
         String instanceId = activityRequestMap.get(requestCode);
         if (instanceId != null) {
-            for (Router router : routerMap.values()) {
+            for (Router router : getRouters()) {
                 router.onActivityResult(instanceId, requestCode, resultCode, data);
             }
         }
@@ -216,7 +232,7 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
 
         String instanceId = permissionRequestMap.get(requestCode);
         if (instanceId != null) {
-            for (Router router : routerMap.values()) {
+            for (Router router : getRouters()) {
                 router.onRequestPermissionsResult(instanceId, requestCode, permissions, grantResults);
             }
         }
@@ -224,7 +240,7 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
 
     @Override
     public boolean shouldShowRequestPermissionRationale(@NonNull String permission) {
-        for (Router router : routerMap.values()) {
+        for (Router router : getRouters()) {
             Boolean handled = router.handleRequestedPermission(permission);
             if (handled != null) {
                 return handled;
@@ -237,7 +253,7 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
     public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
         super.onCreateOptionsMenu(menu, inflater);
 
-        for (Router router : routerMap.values()) {
+        for (Router router : getRouters()) {
             router.onCreateOptionsMenu(menu, inflater);
         }
     }
@@ -246,14 +262,14 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
     public void onPrepareOptionsMenu(Menu menu) {
         super.onPrepareOptionsMenu(menu);
 
-        for (Router router : routerMap.values()) {
+        for (Router router : getRouters()) {
             router.onPrepareOptionsMenu(menu);
         }
     }
 
     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
-        for (Router router : routerMap.values()) {
+        for (Router router : getRouters()) {
             if (router.onOptionsItemSelected(item)) {
                 return true;
             }
@@ -306,13 +322,19 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
     public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
         if (this.activity == null && findInActivity(activity) == LifecycleHandler.this) {
             this.activity = activity;
+
+            for (ActivityHostedRouter router : new ArrayList<>(routerMap.values())) {
+                router.onContextAvailable();
+            }
         }
     }
 
     @Override
     public void onActivityStarted(Activity activity) {
         if (this.activity == activity) {
-            for (Router router : routerMap.values()) {
+            hasPreparedForHostDetach = false;
+
+            for (Router router : getRouters()) {
                 router.onActivityStarted(activity);
             }
         }
@@ -321,7 +343,7 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
     @Override
     public void onActivityResumed(Activity activity) {
         if (this.activity == activity) {
-            for (Router router : routerMap.values()) {
+            for (Router router : getRouters()) {
                 router.onActivityResumed(activity);
             }
         }
@@ -330,7 +352,7 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
     @Override
     public void onActivityPaused(Activity activity) {
         if (this.activity == activity) {
-            for (Router router : routerMap.values()) {
+            for (Router router : getRouters()) {
                 router.onActivityPaused(activity);
             }
         }
@@ -339,7 +361,9 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
     @Override
     public void onActivityStopped(Activity activity) {
         if (this.activity == activity) {
-            for (Router router : routerMap.values()) {
+            prepareForHostDetachIfNeeded();
+
+            for (Router router : getRouters()) {
                 router.onActivityStopped(activity);
             }
         }
@@ -348,7 +372,9 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
     @Override
     public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
         if (this.activity == activity) {
-            for (Router router : routerMap.values()) {
+            prepareForHostDetachIfNeeded();
+
+            for (Router router : getRouters()) {
                 Bundle bundle = new Bundle();
                 router.saveInstanceState(bundle);
                 outState.putBundle(KEY_ROUTER_STATE_PREFIX + router.getContainerId(), bundle);
@@ -357,7 +383,19 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
     }
 
     @Override
-    public void onActivityDestroyed(Activity activity) { }
+    public void onActivityDestroyed(Activity activity) {
+        activeLifecycleHandlers.remove(activity);
+    }
+
+    private void prepareForHostDetachIfNeeded() {
+        if (!hasPreparedForHostDetach) {
+            hasPreparedForHostDetach = true;
+
+            for (Router router : getRouters()) {
+                router.prepareForHostDetach();
+            }
+        }
+    }
 
     private static class PendingPermissionRequest implements Parcelable {
         final String instanceId;
@@ -370,7 +408,7 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
             this.requestCode = requestCode;
         }
 
-        private PendingPermissionRequest(Parcel in) {
+        PendingPermissionRequest(Parcel in) {
             instanceId = in.readString();
             permissions = in.createStringArray();
             requestCode = in.readInt();

conductor/src/main/java/com/bluelinelabs/conductor/internal/NoOpControllerChangeHandler.java

@@ -1,7 +1,7 @@
 package com.bluelinelabs.conductor.internal;
 
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.view.View;
 import android.view.ViewGroup;
 
@@ -24,4 +24,4 @@ public class NoOpControllerChangeHandler extends ControllerChangeHandler {
     public boolean isReusable() {
         return true;
     }
-}
+}

conductor/src/main/java/com/bluelinelabs/conductor/internal/StringSparseArrayParceler.java

@@ -2,7 +2,7 @@ package com.bluelinelabs.conductor.internal;
 
 import android.os.Parcel;
 import android.os.Parcelable;
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 import android.util.SparseArray;
 
 public class StringSparseArrayParceler implements Parcelable {
@@ -13,7 +13,7 @@ public class StringSparseArrayParceler implements Parcelable {
         this.stringSparseArray = stringSparseArray;
     }
 
-    private StringSparseArrayParceler(@NonNull Parcel in) {
+    StringSparseArrayParceler(@NonNull Parcel in) {
         stringSparseArray = new SparseArray<>();
 
         final int size = in.readInt();

conductor/src/main/java/com/bluelinelabs/conductor/internal/TransactionIndexer.java

@@ -1,7 +1,7 @@
 package com.bluelinelabs.conductor.internal;
 
 import android.os.Bundle;
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 
 public class TransactionIndexer {
 

conductor/src/main/java/com/bluelinelabs/conductor/internal/ViewAttachHandler.java

@@ -23,11 +23,11 @@ public class ViewAttachHandler implements OnAttachStateChangeListener {
     }
 
     private boolean rootAttached = false;
-    private boolean childrenAttached = false;
+    boolean childrenAttached = false;
     private boolean activityStopped = false;
     private ReportedState reportedState = ReportedState.VIEW_DETACHED;
     private ViewAttachListener attachListener;
-    private OnAttachStateChangeListener childOnAttachStateChangeListener;
+    OnAttachStateChangeListener childOnAttachStateChangeListener;
 
     public ViewAttachHandler(ViewAttachListener attachListener) {
         this.attachListener = attachListener;
@@ -81,7 +81,7 @@ public class ViewAttachHandler implements OnAttachStateChangeListener {
         reportDetached(true);
     }
 
-    private void reportAttached() {
+    void reportAttached() {
         if (rootAttached && childrenAttached && !activityStopped && reportedState != ReportedState.ATTACHED) {
             reportedState = ReportedState.ATTACHED;
             attachListener.onAttached();

conductor/src/test/java/com/bluelinelabs/conductor/ControllerLifecycleActivityReferenceTests.java

@@ -1,7 +1,7 @@
 package com.bluelinelabs.conductor;
 
 import android.os.Bundle;
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 import android.view.View;
 import android.view.ViewGroup;
 

conductor/src/test/java/com/bluelinelabs/conductor/ControllerLifecycleCallbacksTests.java

@@ -1,11 +1,14 @@
 package com.bluelinelabs.conductor;
 
+import android.content.Context;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 import android.view.View;
 import android.view.ViewGroup;
 
 import com.bluelinelabs.conductor.Controller.LifecycleListener;
+import com.bluelinelabs.conductor.Controller.RetainViewMode;
+import com.bluelinelabs.conductor.changehandler.SimpleSwapChangeHandler;
 import com.bluelinelabs.conductor.util.ActivityProxy;
 import com.bluelinelabs.conductor.util.CallState;
 import com.bluelinelabs.conductor.util.MockChangeHandler;
@@ -20,8 +23,10 @@ import org.robolectric.RobolectricTestRunner;
 import org.robolectric.annotation.Config;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
 
 @RunWith(RobolectricTestRunner.class)
 @Config(manifest = Config.NONE)
@@ -49,7 +54,7 @@ public class ControllerLifecycleCallbacksTests {
     public void setup() {
         createActivityController(null, true);
 
-        currentCallState = new CallState();
+        currentCallState = new CallState(false);
     }
 
     @Test
@@ -57,7 +62,7 @@ public class ControllerLifecycleCallbacksTests {
         TestController controller = new TestController();
         attachLifecycleListener(controller);
 
-        CallState expectedCallState = new CallState();
+        CallState expectedCallState = new CallState(false);
 
         assertCalls(expectedCallState, controller);
         router.pushController(RouterTransaction.with(controller)
@@ -78,7 +83,7 @@ public class ControllerLifecycleCallbacksTests {
         TestController controller = new TestController();
         attachLifecycleListener(controller);
 
-        CallState expectedCallState = new CallState();
+        CallState expectedCallState = new CallState(false);
 
         assertCalls(expectedCallState, controller);
         router.pushController(RouterTransaction.with(controller)
@@ -109,7 +114,7 @@ public class ControllerLifecycleCallbacksTests {
         TestController controller = new TestController();
         attachLifecycleListener(controller);
 
-        CallState expectedCallState = new CallState();
+        CallState expectedCallState = new CallState(false);
 
         assertCalls(expectedCallState, controller);
         router.pushController(RouterTransaction.with(controller)
@@ -131,6 +136,7 @@ public class ControllerLifecycleCallbacksTests {
 
         activityProxy.destroy();
 
+        expectedCallState.contextUnavailableCalls++;
         expectedCallState.destroyCalls++;
         assertCalls(expectedCallState, controller);
     }
@@ -140,7 +146,7 @@ public class ControllerLifecycleCallbacksTests {
         TestController controller = new TestController();
         attachLifecycleListener(controller);
 
-        CallState expectedCallState = new CallState();
+        CallState expectedCallState = new CallState(false);
 
         assertCalls(expectedCallState, controller);
         router.pushController(RouterTransaction.with(controller)
@@ -167,11 +173,13 @@ public class ControllerLifecycleCallbacksTests {
         assertCalls(expectedCallState, controller);
 
         activityProxy.destroy();
+        expectedCallState.contextUnavailableCalls++;
         assertCalls(expectedCallState, controller);
 
         createActivityController(bundle, false);
         controller = (TestController)router.getControllerWithTag("root");
 
+        expectedCallState.contextAvailableCalls++;
         expectedCallState.restoreInstanceStateCalls++;
         expectedCallState.restoreViewStateCalls++;
         expectedCallState.changeStartCalls++;
@@ -184,6 +192,7 @@ public class ControllerLifecycleCallbacksTests {
         currentCallState.changeEndCalls = controller.currentCallState.changeEndCalls;
         currentCallState.createViewCalls = controller.currentCallState.createViewCalls;
         currentCallState.attachCalls = controller.currentCallState.attachCalls;
+        currentCallState.contextAvailableCalls = controller.currentCallState.contextAvailableCalls;
 
         assertCalls(expectedCallState, controller);
 
@@ -204,7 +213,7 @@ public class ControllerLifecycleCallbacksTests {
         TestController controller = new TestController();
         attachLifecycleListener(controller);
 
-        CallState expectedCallState = new CallState();
+        CallState expectedCallState = new CallState(false);
 
         assertCalls(expectedCallState, controller);
         router.pushController(RouterTransaction.with(controller)
@@ -222,12 +231,14 @@ public class ControllerLifecycleCallbacksTests {
         assertCalls(expectedCallState, controller);
 
         activityProxy.resume();
+
+        assertCalls(expectedCallState, controller);
     }
 
     @Test
     public void testLifecycleCallOrder() {
         final TestController testController = new TestController();
-        final CallState callState = new CallState();
+        final CallState callState = new CallState(false);
 
         testController.addLifecycleListener(new LifecycleListener() {
             @Override
@@ -443,7 +454,7 @@ public class ControllerLifecycleCallbacksTests {
         TestController child = new TestController();
         attachLifecycleListener(child);
 
-        CallState expectedCallState = new CallState();
+        CallState expectedCallState = new CallState(false);
 
         assertCalls(expectedCallState, child);
 
@@ -470,7 +481,7 @@ public class ControllerLifecycleCallbacksTests {
         TestController child = new TestController();
         attachLifecycleListener(child);
 
-        CallState expectedCallState = new CallState();
+        CallState expectedCallState = new CallState(false);
 
         assertCalls(expectedCallState, child);
 
@@ -486,15 +497,49 @@ public class ControllerLifecycleCallbacksTests {
 
         expectedCallState.detachCalls++;
         expectedCallState.destroyViewCalls++;
+        expectedCallState.contextUnavailableCalls++;
         expectedCallState.destroyCalls++;
 
         assertCalls(expectedCallState, child);
     }
 
+    @Test
+    public void testChildLifecycleOrderingAfterUnexpectedAttach() {
+        Controller parent = new TestController();
+        parent.setRetainViewMode(RetainViewMode.RETAIN_DETACH);
+        router.pushController(RouterTransaction.with(parent)
+                .pushChangeHandler(MockChangeHandler.defaultHandler())
+                .popChangeHandler(MockChangeHandler.defaultHandler()));
+
+        TestController child = new TestController();
+        child.setRetainViewMode(RetainViewMode.RETAIN_DETACH);
+        Router childRouter = parent.getChildRouter((ViewGroup)parent.getView().findViewById(TestController.VIEW_ID));
+        childRouter
+                .setRoot(RouterTransaction.with(child)
+                        .pushChangeHandler(new SimpleSwapChangeHandler())
+                        .popChangeHandler(new SimpleSwapChangeHandler()));
+
+        assertTrue(parent.isAttached());
+        assertTrue(child.isAttached());
+
+        ViewUtils.reportAttached(parent.getView(), false, true);
+        assertFalse(parent.isAttached());
+        assertFalse(child.isAttached());
+
+        ViewUtils.reportAttached(child.getView(), true);
+        assertFalse(parent.isAttached());
+        assertFalse(child.isAttached());
+
+        ViewUtils.reportAttached(parent.getView(), true);
+        assertTrue(parent.isAttached());
+        assertTrue(child.isAttached());
+    }
+
     private MockChangeHandler getPushHandler(final CallState expectedCallState, final TestController controller) {
         return MockChangeHandler.listeningChangeHandler(new ChangeHandlerListener() {
             @Override
             public void willStartChange() {
+                expectedCallState.contextAvailableCalls++;
                 expectedCallState.changeStartCalls++;
                 expectedCallState.createViewCalls++;
                 assertCalls(expectedCallState, controller);
@@ -526,6 +571,7 @@ public class ControllerLifecycleCallbacksTests {
             public void didAttachOrDetach() {
                 expectedCallState.destroyViewCalls++;
                 expectedCallState.detachCalls++;
+                expectedCallState.contextUnavailableCalls++;
                 expectedCallState.destroyCalls++;
                 assertCalls(expectedCallState, controller);
             }
@@ -555,6 +601,16 @@ public class ControllerLifecycleCallbacksTests {
                 currentCallState.changeEndCalls++;
             }
 
+            @Override
+            public void postContextAvailable(@NonNull Controller controller, @NonNull Context context) {
+                currentCallState.contextAvailableCalls++;
+            }
+
+            @Override
+            public void postContextUnavailable(@NonNull Controller controller) {
+                currentCallState.contextUnavailableCalls++;
+            }
+
             @Override
             public void postCreateView(@NonNull Controller controller, @NonNull View view) {
                 currentCallState.createViewCalls++;

conductor/src/test/java/com/bluelinelabs/conductor/ReattachCaseTests.java

@@ -6,6 +6,7 @@ import android.view.ViewGroup;
 import com.bluelinelabs.conductor.util.ActivityProxy;
 import com.bluelinelabs.conductor.util.MockChangeHandler;
 import com.bluelinelabs.conductor.util.TestController;
+import com.bluelinelabs.conductor.util.ViewUtils;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -232,6 +233,60 @@ public class ReattachCaseTests {
         assertFalse(childController.isAttached());
     }
 
+    // Attempt to test https://github.com/bluelinelabs/Conductor/issues/367
+    @Test
+    public void testViewIsAttachedAfterStartedActivityIsRecreated() {
+        Controller controller1 = new TestController();
+        Controller controller2 = new TestController();
+
+        router.setRoot(RouterTransaction.with(controller1));
+        assertTrue(controller1.isAttached());
+
+        // Lock screen
+        Bundle bundle = new Bundle();
+        activityProxy.pause().saveInstanceState(bundle).stop(false);
+
+        // Push a 2nd controller, which will rotate the screen once it unlocked
+        router.pushController(RouterTransaction.with(controller2));
+        assertTrue(controller2.isAttached());
+        assertTrue(controller2.getNeedsAttach());
+
+        // Unlock screen and rotate
+        activityProxy.start();
+        activityProxy.rotate();
+
+        assertTrue(controller2.isAttached());
+    }
+
+    @Test
+    public void testPopMiddleControllerAttaches() {
+        Controller controller1 = new TestController();
+        Controller controller2 = new TestController();
+        Controller controller3 = new TestController();
+
+        router.setRoot(RouterTransaction.with(controller1));
+        router.pushController(RouterTransaction.with(controller2));
+        router.pushController(RouterTransaction.with(controller3));
+        router.popController(controller2);
+
+        assertFalse(controller1.isAttached());
+        assertFalse(controller2.isAttached());
+        assertTrue(controller3.isAttached());
+
+        controller1 = new TestController();
+        controller2 = new TestController();
+        controller3 = new TestController();
+
+        router.setRoot(RouterTransaction.with(controller1));
+        router.pushController(RouterTransaction.with(controller2));
+        router.pushController(RouterTransaction.with(controller3).pushChangeHandler(MockChangeHandler.noRemoveViewOnPushHandler()));
+        router.popController(controller2);
+
+        assertTrue(controller1.isAttached());
+        assertFalse(controller2.isAttached());
+        assertTrue(controller3.isAttached());
+    }
+
     private void sleepWakeDevice() {
         activityProxy.saveInstanceState(new Bundle()).pause();
         activityProxy.resume();

conductor/src/test/java/com/bluelinelabs/conductor/RouterChangeHandlerTests.java

@@ -193,10 +193,10 @@ public class RouterChangeHandlerTests {
         TestController newController1 = new TestController();
         TestController newController2 = new TestController();
         MockChangeHandler setBackstackHandler = MockChangeHandler.taggedHandler("setBackstackHandler", true);
-
+        MockChangeHandler pushController2Handler = MockChangeHandler.noRemoveViewOnPushHandler("pushController2");
         List<RouterTransaction> newBackstack = Arrays.asList(
                 RouterTransaction.with(newController1),
-                RouterTransaction.with(newController2).pushChangeHandler(MockChangeHandler.noRemoveViewOnPushHandler())
+                RouterTransaction.with(newController2).pushChangeHandler(pushController2Handler)
         );
 
         router.setBackstack(newBackstack, setBackstackHandler);
@@ -226,14 +226,129 @@ public class RouterChangeHandlerTests {
         assertEquals(newController2.getView(), newController1.changeHandlerHistory.latestToView());
         assertEquals(initialView1, newController1.changeHandlerHistory.fromViewAt(0));
         assertEquals(newController1.getView(), newController1.changeHandlerHistory.latestFromView());
-        assertEquals(setBackstackHandler.tag, newController1.changeHandlerHistory.latestChangeHandler().tag);
+        assertEquals(setBackstackHandler.tag, newController1.changeHandlerHistory.changeHandlerAt(0).tag);
+        assertEquals(pushController2Handler.tag, newController1.changeHandlerHistory.latestChangeHandler().tag);
         assertTrue(newController1.changeHandlerHistory.latestIsPush());
 
         assertNotNull(newController2.changeHandlerHistory.latestToView());
         assertEquals(newController2.getView(), newController2.changeHandlerHistory.latestToView());
         assertEquals(newController1.getView(), newController2.changeHandlerHistory.latestFromView());
-        assertEquals(setBackstackHandler.tag, newController2.changeHandlerHistory.latestChangeHandler().tag);
+        assertEquals(pushController2Handler.tag, newController2.changeHandlerHistory.latestChangeHandler().tag);
         assertTrue(newController2.changeHandlerHistory.latestIsPush());
     }
 
+    @Test
+    public void testSetBackstackForPushHandlers() {
+        TestController initialController = new TestController();
+        MockChangeHandler initialPushHandler = MockChangeHandler.taggedHandler("initialPush1", true);
+        MockChangeHandler initialPopHandler = MockChangeHandler.taggedHandler("initialPop1", true);
+        RouterTransaction initialTransaction = RouterTransaction.with(initialController).pushChangeHandler(initialPushHandler).popChangeHandler(initialPopHandler);
+        router.setRoot(initialTransaction);
+        View initialView = initialController.getView();
+
+        TestController newController = new TestController();
+        MockChangeHandler setBackstackHandler = MockChangeHandler.taggedHandler("setBackstackHandler", true);
+
+        List<RouterTransaction> newBackstack = Arrays.asList(
+                initialTransaction,
+                RouterTransaction.with(newController)
+        );
+
+        router.setBackstack(newBackstack, setBackstackHandler);
+
+        assertTrue(initialController.changeHandlerHistory.isValidHistory);
+        assertTrue(newController.changeHandlerHistory.isValidHistory);
+
+        assertEquals(2, initialController.changeHandlerHistory.size());
+        assertEquals(1, newController.changeHandlerHistory.size());
+
+        assertNotNull(initialController.changeHandlerHistory.latestToView());
+        assertEquals(newController.getView(), initialController.changeHandlerHistory.latestToView());
+        assertEquals(initialView, initialController.changeHandlerHistory.latestFromView());
+        assertEquals(setBackstackHandler.tag, initialController.changeHandlerHistory.latestChangeHandler().tag);
+        assertTrue(initialController.changeHandlerHistory.latestIsPush());
+        assertTrue(newController.changeHandlerHistory.latestIsPush());
+    }
+
+    @Test
+    public void testSetBackstackForInvertHandlersWithRemovesView() {
+        TestController initialController1 = new TestController();
+        MockChangeHandler initialPushHandler1 = MockChangeHandler.taggedHandler("initialPush1", true);
+        MockChangeHandler initialPopHandler1 = MockChangeHandler.taggedHandler("initialPop1", true);
+        RouterTransaction initialTransaction1 = RouterTransaction.with(initialController1).pushChangeHandler(initialPushHandler1).popChangeHandler(initialPopHandler1);
+        router.setRoot(initialTransaction1);
+        TestController initialController2 = new TestController();
+        MockChangeHandler initialPushHandler2 = MockChangeHandler.taggedHandler("initialPush2", true);
+        MockChangeHandler initialPopHandler2 = MockChangeHandler.taggedHandler("initialPop2", true);
+        RouterTransaction initialTransaction2 = RouterTransaction.with(initialController2).pushChangeHandler(initialPushHandler2).popChangeHandler(initialPopHandler2);
+        router.pushController(initialTransaction2);
+
+        View initialView2 = initialController2.getView();
+
+        MockChangeHandler setBackstackHandler = MockChangeHandler.taggedHandler("setBackstackHandler", true);
+        List<RouterTransaction> newBackstack = Arrays.asList(
+                initialTransaction2,
+                initialTransaction1
+        );
+
+        router.setBackstack(newBackstack, setBackstackHandler);
+
+        assertTrue(initialController1.changeHandlerHistory.isValidHistory);
+        assertTrue(initialController2.changeHandlerHistory.isValidHistory);
+
+        assertEquals(3, initialController1.changeHandlerHistory.size());
+        assertEquals(2, initialController2.changeHandlerHistory.size());
+
+        assertNotNull(initialController1.changeHandlerHistory.latestToView());
+        assertEquals(initialView2, initialController1.changeHandlerHistory.latestFromView());
+        assertEquals(setBackstackHandler.tag, initialController1.changeHandlerHistory.latestChangeHandler().tag);
+        assertFalse(initialController1.changeHandlerHistory.latestIsPush());
+
+        assertNotNull(initialController2.changeHandlerHistory.latestToView());
+        assertEquals(initialView2, initialController2.changeHandlerHistory.latestFromView());
+        assertEquals(setBackstackHandler.tag, initialController2.changeHandlerHistory.latestChangeHandler().tag);
+        assertFalse(initialController2.changeHandlerHistory.latestIsPush());
+    }
+
+    @Test
+    public void testSetBackstackForInvertHandlersWithoutRemovesView() {
+        TestController initialController1 = new TestController();
+        MockChangeHandler initialPushHandler1 = MockChangeHandler.taggedHandler("initialPush1", true);
+        MockChangeHandler initialPopHandler1 = MockChangeHandler.taggedHandler("initialPop1", true);
+        RouterTransaction initialTransaction1 = RouterTransaction.with(initialController1).pushChangeHandler(initialPushHandler1).popChangeHandler(initialPopHandler1);
+        router.setRoot(initialTransaction1);
+        TestController initialController2 = new TestController();
+        MockChangeHandler initialPushHandler2 = MockChangeHandler.taggedHandler("initialPush2", false);
+        MockChangeHandler initialPopHandler2 = MockChangeHandler.taggedHandler("initialPop2", false);
+        RouterTransaction initialTransaction2 = RouterTransaction.with(initialController2).pushChangeHandler(initialPushHandler2).popChangeHandler(initialPopHandler2);
+        router.pushController(initialTransaction2);
+
+        View initialView1 = initialController1.getView();
+        View initialView2 = initialController2.getView();
+
+        MockChangeHandler setBackstackHandler = MockChangeHandler.taggedHandler("setBackstackHandler", true);
+        List<RouterTransaction> newBackstack = Arrays.asList(
+                initialTransaction2,
+                initialTransaction1
+        );
+
+        router.setBackstack(newBackstack, setBackstackHandler);
+
+        assertTrue(initialController1.changeHandlerHistory.isValidHistory);
+        assertTrue(initialController2.changeHandlerHistory.isValidHistory);
+
+        assertEquals(2, initialController1.changeHandlerHistory.size());
+        assertEquals(2, initialController2.changeHandlerHistory.size());
+
+        assertNotNull(initialController1.changeHandlerHistory.latestToView());
+        assertEquals(initialView1, initialController1.changeHandlerHistory.latestFromView());
+        assertEquals(initialPushHandler2.tag, initialController1.changeHandlerHistory.latestChangeHandler().tag);
+        assertTrue(initialController1.changeHandlerHistory.latestIsPush());
+
+        assertNull(initialController2.changeHandlerHistory.latestToView());
+        assertEquals(initialView2, initialController2.changeHandlerHistory.latestFromView());
+        assertEquals(setBackstackHandler.tag, initialController2.changeHandlerHistory.latestChangeHandler().tag);
+        assertFalse(initialController2.changeHandlerHistory.latestIsPush());
+    }
+
 }

conductor/src/test/java/com/bluelinelabs/conductor/RouterTests.java

@@ -1,7 +1,10 @@
 package com.bluelinelabs.conductor;
 
+import androidx.annotation.NonNull;
+import android.view.View;
 import android.view.ViewGroup;
 
+import com.bluelinelabs.conductor.Controller.LifecycleListener;
 import com.bluelinelabs.conductor.changehandler.FadeChangeHandler;
 import com.bluelinelabs.conductor.changehandler.HorizontalChangeHandler;
 import com.bluelinelabs.conductor.util.ActivityProxy;
@@ -125,6 +128,31 @@ public class RouterTests {
         assertNull(router.getControllerWithTag(controller2Tag));
     }
 
+    @Test
+    public void testPopControllerConcurrentModificationException() {
+        int step = 1;
+        for (int i = 0; i < 10; i++, step++) {
+            router.pushController(RouterTransaction.with(new TestController()).tag("1"));
+            router.pushController(RouterTransaction.with(new TestController()).tag("2"));
+            router.pushController(RouterTransaction.with(new TestController()).tag("3"));
+
+            String tag;
+            if (step == 1) {
+                tag = "1";
+            } else if (step == 2) {
+                tag = "2";
+            } else {
+                tag = "3";
+                step = 0;
+            }
+            Controller controller = router.getControllerWithTag(tag);
+            if (controller != null) {
+                router.popController(controller);
+            }
+            router.popToRoot();
+        }
+    }
+
     @Test
     public void testPopToTag() {
         String controller1Tag = "controller1";
@@ -431,4 +459,37 @@ public class RouterTests {
         assertEquals(0, router.container.getChildCount());
     }
 
+    @Test
+    public void testIsBeingDestroyed() {
+        final LifecycleListener lifecycleListener = new LifecycleListener() {
+            @Override
+            public void preDestroyView(@NonNull Controller controller, @NonNull View view) {
+                assertTrue(controller.isBeingDestroyed());
+            }
+        };
+
+        Controller controller1 = new TestController();
+        Controller controller2 = new TestController();
+        controller2.addLifecycleListener(lifecycleListener);
+
+        router.setRoot(RouterTransaction.with(controller1));
+        router.pushController(RouterTransaction.with(controller2));
+        assertFalse(controller1.isBeingDestroyed());
+        assertFalse(controller2.isBeingDestroyed());
+
+        router.popCurrentController();
+        assertFalse(controller1.isBeingDestroyed());
+        assertTrue(controller2.isBeingDestroyed());
+
+        Controller controller3 = new TestController();
+        controller3.addLifecycleListener(lifecycleListener);
+        router.pushController(RouterTransaction.with(controller3));
+        assertFalse(controller1.isBeingDestroyed());
+        assertFalse(controller3.isBeingDestroyed());
+
+        router.popToRoot();
+        assertFalse(controller1.isBeingDestroyed());
+        assertTrue(controller3.isBeingDestroyed());
+    }
+
 }

conductor/src/test/java/com/bluelinelabs/conductor/ViewLeakTests.java

@@ -1,8 +1,8 @@
 package com.bluelinelabs.conductor;
 
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.view.View;
 import android.view.ViewGroup;
 

conductor/src/test/java/com/bluelinelabs/conductor/util/ActivityProxy.java

@@ -1,10 +1,10 @@
 package com.bluelinelabs.conductor.util;
 
 import android.os.Bundle;
-import android.support.annotation.IdRes;
+import androidx.annotation.IdRes;
 
 import org.robolectric.Robolectric;
-import org.robolectric.util.ActivityController;
+import org.robolectric.android.controller.ActivityController;
 
 public class ActivityProxy {
 

conductor/src/test/java/com/bluelinelabs/conductor/util/CallState.java

@@ -19,10 +19,8 @@ public class CallState implements Parcelable {
     public int onActivityResultCalls;
     public int onRequestPermissionsResultCalls;
     public int createOptionsMenuCalls;
-
-    public CallState() {
-        this(false);
-    }
+    public int contextAvailableCalls;
+    public int contextUnavailableCalls;
 
     public CallState(boolean setupForAddedController) {
         if (setupForAddedController) {
@@ -30,6 +28,7 @@ public class CallState implements Parcelable {
             changeEndCalls++;
             createViewCalls++;
             attachCalls++;
+            contextAvailableCalls++;
         }
     }
 
@@ -42,8 +41,14 @@ public class CallState implements Parcelable {
             return false;
         }
 
-        CallState callState = (CallState)o;
+        CallState callState = (CallState) o;
 
+        if (contextAvailableCalls != callState.contextAvailableCalls) {
+            return false;
+        }
+        if (contextUnavailableCalls != callState.contextUnavailableCalls) {
+            return false;
+        }
         if (changeStartCalls != callState.changeStartCalls) {
             return false;
         }
@@ -102,6 +107,8 @@ public class CallState implements Parcelable {
         result = 31 * result + onActivityResultCalls;
         result = 31 * result + onRequestPermissionsResultCalls;
         result = 31 * result + createOptionsMenuCalls;
+        result = 31 * result + contextAvailableCalls;
+        result = 31 * result + contextUnavailableCalls;
         return result;
     }
 
@@ -122,6 +129,8 @@ public class CallState implements Parcelable {
                 "\n    onActivityResultCalls=" + onActivityResultCalls +
                 "\n    onRequestPermissionsResultCalls=" + onRequestPermissionsResultCalls +
                 "\n    createOptionsMenuCalls=" + createOptionsMenuCalls +
+                "\n    contextAvailableCalls=" + contextAvailableCalls +
+                "\n    contextUnavailableCalls=" + contextUnavailableCalls +
                 "}\n";
     }
 
@@ -144,11 +153,13 @@ public class CallState implements Parcelable {
         out.writeInt(onActivityResultCalls);
         out.writeInt(onRequestPermissionsResultCalls);
         out.writeInt(createOptionsMenuCalls);
+        out.writeInt(contextAvailableCalls);
+        out.writeInt(contextUnavailableCalls);
     }
 
-    public static final Parcelable.Creator<CallState> CREATOR  = new Parcelable.Creator<CallState>() {
+    public static final Parcelable.Creator<CallState> CREATOR = new Parcelable.Creator<CallState>() {
         public CallState createFromParcel(Parcel in) {
-            CallState state = new CallState();
+            CallState state = new CallState(false);
 
             state.changeStartCalls = in.readInt();
             state.changeEndCalls = in.readInt();
@@ -164,6 +175,8 @@ public class CallState implements Parcelable {
             state.onActivityResultCalls = in.readInt();
             state.onRequestPermissionsResultCalls = in.readInt();
             state.createOptionsMenuCalls = in.readInt();
+            state.contextAvailableCalls = in.readInt();
+            state.contextUnavailableCalls = in.readInt();
 
             return state;
         }
@@ -172,4 +185,4 @@ public class CallState implements Parcelable {
             return new CallState[size];
         }
     };
-}
+}

conductor/src/test/java/com/bluelinelabs/conductor/util/MockChangeHandler.java

@@ -1,8 +1,8 @@
 package com.bluelinelabs.conductor.util;
 
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import android.view.View;
 import android.view.ViewGroup;
 
@@ -34,6 +34,10 @@ public class MockChangeHandler extends ControllerChangeHandler {
         return new MockChangeHandler(false, null, null);
     }
 
+    public static MockChangeHandler noRemoveViewOnPushHandler(String tag) {
+        return new MockChangeHandler(false, tag, null);
+    }
+
     public static MockChangeHandler listeningChangeHandler(@NonNull ChangeHandlerListener listener) {
         return new MockChangeHandler(true, null, listener);
     }
@@ -48,6 +52,7 @@ public class MockChangeHandler extends ControllerChangeHandler {
 
     private MockChangeHandler(boolean removesFromViewOnPush, String tag, ChangeHandlerListener listener) {
         this.removesFromViewOnPush = removesFromViewOnPush;
+        this.tag = tag;
 
         if (listener == null) {
             this.listener = new ChangeHandlerListener() { };

conductor/src/test/java/com/bluelinelabs/conductor/util/TestController.java

@@ -1,9 +1,10 @@
 package com.bluelinelabs.conductor.util;
 
+import android.content.Context;
 import android.content.Intent;
 import android.os.Bundle;
-import android.support.annotation.IdRes;
-import android.support.annotation.NonNull;
+import androidx.annotation.IdRes;
+import androidx.annotation.NonNull;
 import android.view.LayoutInflater;
 import android.view.Menu;
 import android.view.MenuInflater;
@@ -23,7 +24,7 @@ public class TestController extends Controller {
 
     private static final String KEY_CALL_STATE = "TestController.currentCallState";
 
-    public CallState currentCallState = new CallState();
+    public CallState currentCallState = new CallState(false);
     public ChangeHandlerHistory changeHandlerHistory = new ChangeHandlerHistory();
 
     @NonNull
@@ -63,6 +64,18 @@ public class TestController extends Controller {
         }
     }
 
+    @Override
+    protected void onContextAvailable(@NonNull Context context) {
+        super.onContextAvailable(context);
+        currentCallState.contextAvailableCalls++;
+    }
+
+    @Override
+    protected void onContextUnavailable() {
+        super.onContextUnavailable();
+        currentCallState.contextUnavailableCalls++;
+    }
+
     @Override
     protected void onAttach(@NonNull View view) {
         super.onAttach(view);

conductor/src/test/java/com/bluelinelabs/conductor/util/ViewUtils.java

@@ -16,7 +16,7 @@ public class ViewUtils {
 
     public static void reportAttached(View view, boolean attached, boolean propogateToChildren) {
         if (view instanceof AttachFakingFrameLayout) {
-            ((AttachFakingFrameLayout)view).setAttached(attached, false);
+            ((AttachFakingFrameLayout) view).setAttached(attached, false);
         }
 
         List<OnAttachStateChangeListener> listeners = getAttachStateListeners(view);
@@ -44,7 +44,7 @@ public class ViewUtils {
         }
 
         if (propogateToChildren && view instanceof ViewGroup) {
-            ViewGroup viewGroup = (ViewGroup)view;
+            ViewGroup viewGroup = (ViewGroup) view;
             int childCount = viewGroup.getChildCount();
             for (int i = 0; i < childCount; i++) {
                 reportAttached(viewGroup.getChildAt(i), attached, true);

demo/build.gradle

@@ -1,27 +1,11 @@
-buildscript {
-    repositories {
-        jcenter()
-    }
-    dependencies {
-        classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'
-    }
-}
-
 apply plugin: 'com.android.application'
-apply plugin: 'com.neenbedankt.android-apt'
 
 android {
     compileSdkVersion rootProject.ext.compileSdkVersion
-    buildToolsVersion rootProject.ext.buildToolsVersion
-
-    lintOptions {
-        abortOnError true
-        ignore 'UnusedResources'
-    }
 
     compileOptions {
-        sourceCompatibility JavaVersion.VERSION_1_7
-        targetCompatibility JavaVersion.VERSION_1_7
+        sourceCompatibility 1.8
+        targetCompatibility 1.8
     }
 
     defaultConfig {
@@ -46,18 +30,24 @@ android {
 }
 
 dependencies {
-    compile rootProject.ext.supportV4
-    compile rootProject.ext.supportDesign
+    implementation rootProject.ext.androidxAppCompat
+    implementation rootProject.ext.material
 
-    apt rootProject.ext.butterknifeCompiler
-    compile rootProject.ext.butterknife
-    compile rootProject.ext.picasso
+    implementation rootProject.ext.archComponentsLiveDataCore // Fix duplicate classes
 
-    compile project(':conductor-support')
-    compile project(':conductor-rxlifecycle')
-    compile project(':conductor-rxlifecycle2')
+    annotationProcessor rootProject.ext.butterknifeCompiler
+    implementation rootProject.ext.butterknife
+    implementation rootProject.ext.picasso
 
-    debugCompile rootProject.ext.leakCanary
-    releaseCompile rootProject.ext.leakCanaryNoOp
-    testCompile rootProject.ext.leakCanaryNoOp
+    implementation project(':conductor')
+    implementation project(':conductor-modules:viewpager')
+    implementation project(':conductor-modules:rxlifecycle')
+    implementation project(':conductor-modules:rxlifecycle2')
+    implementation project(':conductor-modules:autodispose')
+    implementation project(':conductor-modules:arch-components-lifecycle')
+    implementation project(':conductor-modules:androidx-transition')
+
+    debugImplementation rootProject.ext.leakCanary
+    releaseImplementation rootProject.ext.leakCanaryNoOp
+    testImplementation rootProject.ext.leakCanaryNoOp
 }

demo/src/main/java/com/bluelinelabs/conductor/demo/ActionBarProvider.java

@@ -1,6 +1,6 @@
 package com.bluelinelabs.conductor.demo;
 
-import android.support.v7.app.ActionBar;
+import androidx.appcompat.app.ActionBar;
 
 public interface ActionBarProvider {
     ActionBar getSupportActionBar();

demo/src/main/java/com/bluelinelabs/conductor/demo/MainActivity.java

@@ -1,8 +1,8 @@
 package com.bluelinelabs.conductor.demo;
 
 import android.os.Bundle;
-import android.support.v7.app.AppCompatActivity;
-import android.support.v7.widget.Toolbar;
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.appcompat.widget.Toolbar;
 import android.view.ViewGroup;
 
 import com.bluelinelabs.conductor.Conductor;