Version bump

* [Demo] Remove Butterknife unbinder from MainActivity

* Make deploy_snapshot.sh executable

.travis.yml

@@ -14,13 +14,10 @@ jdk:
   - oraclejdk8
 
 branches:
-  only
+  only:
     - develop
     - master
 
-before_install:
-  - chmod +x .buildscript/deploy_snapshot.sh
-
 after_success:
   - .buildscript/deploy_snapshot.sh
 

README.md

@@ -20,22 +20,22 @@ Conductor is architecture-agnostic and does not try to force any design decision
 ## Installation
 
 ```gradle
-compile 'com.bluelinelabs:conductor:2.0.1'
+compile 'com.bluelinelabs:conductor:2.0.2'
 
 // If you want the components that go along with
 // Android's support libraries (currently just a PagerAdapter):
-compile 'com.bluelinelabs:conductor-support:2.0.1'
+compile 'com.bluelinelabs:conductor-support:2.0.2'
 
 // If you want RxJava/RxAndroid lifecycle support:
-compile 'com.bluelinelabs:conductor-rxlifecycle:2.0.1'
+compile 'com.bluelinelabs:conductor-rxlifecycle:2.0.2'
 ```
 
 SNAPSHOT:
 
 ```gradle
-compile 'com.bluelinelabs:conductor:2.0.2-SNAPSHOT'
-compile 'com.bluelinelabs:conductor-support:2.0.2-SNAPSHOT'
-compile 'com.bluelinelabs:conductor-rxlifecycle:2.0.2-SNAPSHOT'
+compile 'com.bluelinelabs:conductor:2.0.3-SNAPSHOT'
+compile 'com.bluelinelabs:conductor-support:2.0.3-SNAPSHOT'
+compile 'com.bluelinelabs:conductor-rxlifecycle:2.0.3-SNAPSHOT'
 ```
 
 You also have to add the url to the snapshot repository:

build.gradle

@@ -3,7 +3,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.1.2'
+        classpath 'com.android.tools.build:gradle:2.2.0'
     }
 }
 

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

@@ -92,4 +92,9 @@ public class ActivityHostedRouter extends Router {
     List<Router> getSiblingRouters() {
         return lifecycleHandler.getRouters();
     }
+
+    @Override
+    Router getRootRouter() {
+        return this;
+    }
 }

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

@@ -24,6 +24,7 @@ import com.bluelinelabs.conductor.ControllerChangeHandler.ControllerChangeListen
 import com.bluelinelabs.conductor.internal.ClassUtils;
 import com.bluelinelabs.conductor.internal.RouterRequiringFunc;
 
+import java.lang.ref.WeakReference;
 import java.lang.reflect.Constructor;
 import java.util.ArrayDeque;
 import java.util.ArrayList;
@@ -84,6 +85,7 @@ public abstract class Controller {
     private final ArrayList<String> requestedPermissions = new ArrayList<>();
     private final ArrayList<RouterRequiringFunc> onRouterSetListeners = new ArrayList<>();
     private final Deque<Controller> childBackstack = new ArrayDeque<>();
+    private WeakReference<View> destroyedView;
 
     private final ControllerChangeListener childRouterChangeListener = new ControllerChangeListener() {
         @Override
@@ -313,7 +315,10 @@ public abstract class Controller {
      * @return This Controller's target
      */
     public final Controller getTargetController() {
-        return targetInstanceId != null ? router.getControllerWithInstanceId(targetInstanceId) : null;
+        if (targetInstanceId != null) {
+            return router.getRootRouter().getControllerWithInstanceId(targetInstanceId);
+        }
+        return null;
     }
 
     /**
@@ -780,6 +785,10 @@ public abstract class Controller {
 
             view.removeOnAttachStateChangeListener(onAttachStateChangeListener);
             viewIsAttached = false;
+
+            if (isBeingDestroyed) {
+                destroyedView = new WeakReference<>(view);
+            }
             view = null;
 
             for (LifecycleListener lifecycleListener : lifecycleListeners) {
@@ -842,7 +851,7 @@ public abstract class Controller {
         return view;
     }
 
-    final void performDestroy() {
+    private void performDestroy() {
         if (!destroyed) {
             for (LifecycleListener lifecycleListener : lifecycleListeners) {
                 lifecycleListener.preDestroy(this);
@@ -850,10 +859,6 @@ public abstract class Controller {
 
             destroyed = true;
 
-            if (router != null) {
-                router.unregisterForActivityResults(instanceId);
-            }
-
             onDestroy();
 
             parentController = null;
@@ -868,9 +873,13 @@ public abstract class Controller {
         destroy(false);
     }
 
-    final void destroy(boolean removeViews) {
+    private void destroy(boolean removeViews) {
         isBeingDestroyed = true;
 
+        if (router != null) {
+            router.unregisterForActivityResults(instanceId);
+        }
+
         for (ControllerHostedRouter childRouter : childRouters) {
             childRouter.destroy();
         }
@@ -882,7 +891,7 @@ public abstract class Controller {
         }
     }
 
-    final void saveViewState(@NonNull View view) {
+    private void saveViewState(@NonNull View view) {
         hasSavedViewState = true;
 
         viewState = new Bundle();
@@ -900,7 +909,7 @@ public abstract class Controller {
         }
     }
 
-    final void restoreViewState(@NonNull View view) {
+    private void restoreViewState(@NonNull View view) {
         if (viewState != null) {
             view.restoreHierarchyState(viewState.getSparseParcelableArray(KEY_VIEW_STATE_HIERARCHY));
             onRestoreViewState(view, viewState.getBundle(KEY_VIEW_STATE_BUNDLE));
@@ -1025,6 +1034,13 @@ public abstract class Controller {
         for (LifecycleListener lifecycleListener : lifecycleListeners) {
             lifecycleListener.onChangeEnd(this, changeHandler, changeType);
         }
+
+        if (isBeingDestroyed && !viewIsAttached && !attached && destroyedView != null) {
+            View view = destroyedView.get();
+            if (router.container != null && view.getParent() == router.container) {
+                router.container.removeView(view);
+            }
+        }
     }
 
     final void setDetachFrozen(boolean frozen) {
@@ -1062,13 +1078,15 @@ public abstract class Controller {
     }
 
     private void onChildControllerPushed(Controller controller) {
-        childBackstack.add(controller);
-        controller.addLifecycleListener(new LifecycleListener() {
-            @Override
-            public void postDestroy(@NonNull Controller controller) {
-                childBackstack.remove(controller);
-            }
-        });
+        if (!childBackstack.contains(controller)) {
+            childBackstack.add(controller);
+            controller.addLifecycleListener(new LifecycleListener() {
+                @Override
+                public void postDestroy(@NonNull Controller controller) {
+                    childBackstack.remove(controller);
+                }
+            });
+        }
     }
 
     final void setParentController(Controller controller) {

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

@@ -28,10 +28,10 @@ public abstract class ControllerChangeHandler {
     /**
      * Responsible for swapping Views from one Controller to another.
      *
-     * @param container The container these Views are hosted in.
-     * @param from The previous View in the container, if any.
-     * @param to The next View that should be put in the container, if any.
-     * @param isPush True if this is a push transaction, false if it's a pop.
+     * @param container      The container these Views are hosted in.
+     * @param from           The previous View in the container, if any.
+     * @param to             The next View that should be put in the container, if any.
+     * @param isPush         True if this is a push transaction, false if it's a pop.
      * @param changeListener This listener must be called when any transitions or animations are completed.
      */
     public abstract void performChange(@NonNull ViewGroup container, View from, View to, boolean isPush, @NonNull ControllerChangeCompletedListener changeListener);
@@ -59,10 +59,16 @@ public abstract class ControllerChangeHandler {
      * popped before it has completed.
      *
      * @param newHandler the change handler that has caused this push to be aborted
-     * @param newTop the controller that will now be at the top of the backstack
+     * @param newTop     the controller that will now be at the top of the backstack
      */
     public void onAbortPush(@NonNull ControllerChangeHandler newHandler, Controller newTop) { }
 
+    /**
+     * Will be called on change handlers that push a controller if the controller being pushed is
+     * needs to be attached immediately, without any animations or transitions.
+     */
+    public void completeImmediately() { }
+
     final Bundle toBundle() {
         Bundle bundle = new Bundle();
         bundle.putString(KEY_CLASS_NAME, getClass().getName());
@@ -94,6 +100,21 @@ public abstract class ControllerChangeHandler {
         }
     }
 
+    public static void completePushImmediately(String controllerInstanceId) {
+        ControllerChangeHandler changeHandler = inProgressPushHandlers.get(controllerInstanceId);
+        if (changeHandler != null) {
+            changeHandler.completeImmediately();
+        }
+    }
+
+    public static void abortPush(Controller toAbort, Controller newController, ControllerChangeHandler newChangeHandler) {
+        ControllerChangeHandler handlerForPush = inProgressPushHandlers.get(toAbort.getInstanceId());
+        if (handlerForPush != null) {
+            handlerForPush.onAbortPush(newChangeHandler, newController);
+            inProgressPushHandlers.remove(toAbort.getInstanceId());
+        }
+    }
+
     public static void executeChange(final Controller to, final Controller from, boolean isPush, ViewGroup container, ControllerChangeHandler inHandler) {
         executeChange(to, from, isPush, container, inHandler, new ArrayList<ControllerChangeListener>());
     }
@@ -102,14 +123,10 @@ public abstract class ControllerChangeHandler {
         if (container != null) {
             final ControllerChangeHandler handler = inHandler != null ? inHandler : new SimpleSwapChangeHandler();
 
-            if (isPush) {
+            if (isPush && to != null) {
                 inProgressPushHandlers.put(to.getInstanceId(), handler);
-            } else if (from != null) {
-                ControllerChangeHandler handlerForPush = inProgressPushHandlers.get(from.getInstanceId());
-                if (handlerForPush != null) {
-                    handlerForPush.onAbortPush(handler, to);
-                    inProgressPushHandlers.remove(from.getInstanceId());
-                }
+            } else if (!isPush && from != null) {
+                abortPush(from, to, handler);
             }
 
             for (ControllerChangeListener listener : listeners) {
@@ -155,6 +172,10 @@ public abstract class ControllerChangeHandler {
         }
     }
 
+    public boolean removesFromViewOnPush() {
+        return true;
+    }
+
     /**
      * A listener interface useful for allowing external classes to be notified of change events.
      */
@@ -162,21 +183,22 @@ public abstract class ControllerChangeHandler {
         /**
          * Called when a {@link ControllerChangeHandler} has started changing {@link Controller}s
          *
-         * @param to The new Controller
-         * @param from The old Controller
-         * @param isPush True if this is a push operation, or false if it's a pop.
+         * @param to        The new Controller
+         * @param from      The old Controller
+         * @param isPush    True if this is a push operation, or false if it's a pop.
          * @param container The containing ViewGroup
-         * @param handler The change handler being used.
+         * @param handler   The change handler being used.
          */
         void onChangeStarted(Controller to, Controller from, boolean isPush, ViewGroup container, ControllerChangeHandler handler);
 
         /**
          * Called when a {@link ControllerChangeHandler} has completed changing {@link Controller}s
-         * @param to The new Controller
-         * @param from The old Controller
-         * @param isPush True if this was a push operation, or false if it's a pop.
+         *
+         * @param to        The new Controller
+         * @param from      The old Controller
+         * @param isPush    True if this was a push operation, or false if it's a pop.
          * @param container The containing ViewGroup
-         * @param handler The change handler that was used.
+         * @param handler   The change handler that was used.
          */
         void onChangeCompleted(Controller to, Controller from, boolean isPush, ViewGroup container, ControllerChangeHandler handler);
     }

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

@@ -52,7 +52,7 @@ class ControllerHostedRouter extends Router {
                 controller.detach(controller.getView(), true);
             }
         }
-        for (RouterTransaction transaction : backStack) {
+        for (RouterTransaction transaction : backstack) {
             if (transaction.controller.getView() != null) {
                 transaction.controller.detach(transaction.controller.getView(), true);
             }
@@ -64,11 +64,17 @@ class ControllerHostedRouter extends Router {
     }
 
     final void setDetachFrozen(boolean frozen) {
-        for (RouterTransaction transaction : backStack) {
+        for (RouterTransaction transaction : backstack) {
             transaction.controller.setDetachFrozen(frozen);
         }
     }
 
+    @Override
+    void destroy() {
+        setDetachFrozen(false);
+        super.destroy();
+    }
+
     @Override
     public Activity getActivity() {
         return hostController != null ? hostController.getActivity() : null;
@@ -179,4 +185,13 @@ class ControllerHostedRouter extends Router {
         list.addAll(hostController.getRouter().getSiblingRouters());
         return list;
     }
+
+    @Override
+    Router getRootRouter() {
+        if (hostController != null && hostController.getRouter() != null) {
+            return hostController.getRouter().getRootRouter();
+        } else {
+            return this;
+        }
+    }
 }

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

@@ -16,6 +16,7 @@ import com.bluelinelabs.conductor.changehandler.SimpleSwapChangeHandler;
 import com.bluelinelabs.conductor.internal.NoOpControllerChangeHandler;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 
@@ -29,7 +30,7 @@ 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();
+    protected final Backstack backstack = new Backstack();
     private final List<ControllerChangeListener> changeListeners = new ArrayList<>();
     final List<Controller> destroyingControllers = new ArrayList<>();
 
@@ -71,10 +72,12 @@ public abstract class Router {
     /**
      * This should be called by the host Activity when its onBackPressed method is called. The call will be forwarded
      * to its top {@link Controller}. If that controller doesn't handle it, then it will be popped.
+     *
+     * @return Whether or not a back action was handled by the Router
      */
     public boolean handleBack() {
-        if (!backStack.isEmpty()) {
-            if (backStack.peek().controller.handleBack()) {
+        if (!backstack.isEmpty()) {
+            if (backstack.peek().controller.handleBack()) {
                 return true;
             } else if (popCurrentController()) {
                 return true;
@@ -90,7 +93,7 @@ public abstract class Router {
      * @return Whether or not this Router still has controllers remaining on it after popping.
      */
     public boolean popCurrentController() {
-        return popController(backStack.peek().controller);
+        return popController(backstack.peek().controller);
     }
 
     /**
@@ -100,28 +103,28 @@ public abstract class Router {
      * @return Whether or not this Router still has controllers remaining on it after popping.
      */
     public boolean popController(Controller controller) {
-        RouterTransaction topController = backStack.peek();
+        RouterTransaction topController = backstack.peek();
         boolean poppingTopController = topController != null && topController.controller == controller;
 
         if (poppingTopController) {
-            trackDestroyingController(backStack.pop());
+            trackDestroyingController(backstack.pop());
         } else {
-            for (RouterTransaction transaction : backStack) {
+            for (RouterTransaction transaction : backstack) {
                 if (transaction.controller == controller) {
-                    backStack.remove(transaction);
+                    backstack.remove(transaction);
                     break;
                 }
             }
         }
 
         if (poppingTopController) {
-            performControllerChange(backStack.peek(), topController, false);
+            performControllerChange(backstack.peek(), topController, false);
         }
 
         if (popsLastView) {
             return topController != null;
         } else {
-            return !backStack.isEmpty();
+            return !backstack.isEmpty();
         }
     }
 
@@ -132,7 +135,7 @@ public abstract class Router {
      *                    and its push and pop {@link ControllerChangeHandler}, and its tag.
      */
     public void pushController(@NonNull RouterTransaction transaction) {
-        RouterTransaction from = backStack.peek();
+        RouterTransaction from = backstack.peek();
         pushToBackstack(transaction);
         performControllerChange(transaction, from, true);
     }
@@ -144,9 +147,9 @@ public abstract class Router {
      *                    and its push and pop {@link ControllerChangeHandler}, and its tag.
      */
     public void replaceTopController(@NonNull RouterTransaction transaction) {
-        RouterTransaction topTransaction = backStack.peek();
-        if (!backStack.isEmpty()) {
-            trackDestroyingController(backStack.pop());
+        RouterTransaction topTransaction = backstack.peek();
+        if (!backstack.isEmpty()) {
+            trackDestroyingController(backstack.pop());
         }
 
         pushToBackstack(transaction);
@@ -155,7 +158,7 @@ public abstract class Router {
 
     void destroy() {
         popsLastView = true;
-        List<RouterTransaction> poppedControllers = backStack.popAll();
+        List<RouterTransaction> poppedControllers = backstack.popAll();
 
         if (poppedControllers.size() > 0) {
             trackDestroyingControllers(poppedControllers);
@@ -164,9 +167,13 @@ public abstract class Router {
         }
     }
 
+    public int getContainerId() {
+        return container != null ? container.getId() : 0;
+    }
+
     /**
      * If set to true, this router will handle back presses by performing a change handler on the last controller and view
-     * in the stack. This defaults to false so that the developer can either finish its containing Activity or otherwise 
+     * in the stack. This defaults to false so that the developer can either finish its containing Activity or otherwise
      * hide its parent view without any strange artifacting.
      */
     public Router setPopsLastView(boolean popsLastView) {
@@ -190,8 +197,8 @@ public abstract class Router {
      * @return Whether or not any {@link Controller}s were popped in order to get to the root transaction
      */
     public boolean popToRoot(ControllerChangeHandler changeHandler) {
-        if (backStack.size() > 1) {
-            popToTransaction(backStack.root(), changeHandler);
+        if (backstack.size() > 1) {
+            popToTransaction(backstack.root(), changeHandler);
             return true;
         } else {
             return false;
@@ -216,7 +223,7 @@ public abstract class Router {
      * @return Whether or not the {@link Controller} with the passed tag is now at the top
      */
     public boolean popToTag(@NonNull String tag, ControllerChangeHandler changeHandler) {
-        for (RouterTransaction transaction : backStack) {
+        for (RouterTransaction transaction : backstack) {
             if (tag.equals(transaction.tag())) {
                 popToTransaction(transaction, changeHandler);
                 return true;
@@ -232,13 +239,29 @@ public abstract class Router {
      *                    and its push and pop {@link ControllerChangeHandler}, and its tag.
      */
     public void setRoot(@NonNull RouterTransaction transaction) {
-        RouterTransaction currentTop = backStack.peek();
-        removeAllExceptTopAndUnowned();
+        ControllerChangeHandler newHandler = transaction.pushChangeHandler() != null ? transaction.pushChangeHandler() : new SimpleSwapChangeHandler();
 
-        trackDestroyingControllers(backStack.popAll());
+        List<RouterTransaction> visibleTransactions = getVisibleTransactions(backstack.iterator());
+        RouterTransaction rootTransaction = visibleTransactions.size() > 0 ? visibleTransactions.get(0) : null;
+
+        removeAllExceptVisibleAndUnowned();
+
+        trackDestroyingControllers(backstack.popAll());
 
         pushToBackstack(transaction);
-        performControllerChange(transaction, currentTop, true);
+
+        for (int i = visibleTransactions.size() - 1; i > 0; i--) {
+            if (visibleTransactions.get(i).controller.getView() == null) {
+                ControllerChangeHandler.abortPush(visibleTransactions.get(i).controller, transaction.controller, newHandler);
+            } else {
+                performControllerChange(null, visibleTransactions.get(i).controller, true, newHandler);
+            }
+        }
+
+        if (rootTransaction != null && rootTransaction.controller.getView() == null) {
+            ControllerChangeHandler.abortPush(rootTransaction.controller, transaction.controller, newHandler);
+        }
+        performControllerChange(transaction, rootTransaction, true);
     }
 
     /**
@@ -248,7 +271,7 @@ public abstract class Router {
      * @return The matching Controller, if one exists
      */
     public Controller getControllerWithInstanceId(String instanceId) {
-        for (RouterTransaction transaction : backStack) {
+        for (RouterTransaction transaction : backstack) {
             Controller controllerWithId = transaction.controller.findController(instanceId);
             if (controllerWithId != null) {
                 return controllerWithId;
@@ -264,7 +287,7 @@ public abstract class Router {
      * @return The matching Controller, if one exists
      */
     public Controller getControllerWithTag(String tag) {
-        for (RouterTransaction transaction : backStack) {
+        for (RouterTransaction transaction : backstack) {
             if (tag.equals(transaction.tag())) {
                 return transaction.controller;
             }
@@ -276,7 +299,7 @@ public abstract class Router {
      * Returns the number of {@link Controller}s currently in the backstack
      */
     public int getBackstackSize() {
-        return backStack.size();
+        return backstack.size();
     }
 
     /**
@@ -284,7 +307,7 @@ public abstract class Router {
      */
     public List<RouterTransaction> getBackstack() {
         List<RouterTransaction> list = new ArrayList<>();
-        Iterator<RouterTransaction> backstackIterator = backStack.reverseIterator();
+        Iterator<RouterTransaction> backstackIterator = backstack.reverseIterator();
         while (backstackIterator.hasNext()) {
             list.add(backstackIterator.next());
         }
@@ -295,20 +318,45 @@ public abstract class Router {
      * Sets the backstack, transitioning from the current top controller to the top of the new stack (if different)
      * using the passed {@link ControllerChangeHandler}
      *
-     * @param backstack The new backstack
+     * @param newBackstack The new backstack
      * @param changeHandler An optional change handler to be used to handle the transition
      */
-    public void setBackstack(@NonNull List<RouterTransaction> backstack, ControllerChangeHandler changeHandler) {
-        RouterTransaction oldTopTransaction = backStack.peek();
-        Controller oldTop = oldTopTransaction != null ? oldTopTransaction.controller : null;
-        removeAllExceptTopAndUnowned();
+    public void setBackstack(@NonNull List<RouterTransaction> newBackstack, ControllerChangeHandler changeHandler) {
+        List<RouterTransaction> oldVisibleTransactions = getVisibleTransactions(backstack.iterator());
 
-        if (backstack.size() > 0) {
-            Controller newTop = backstack.get(backstack.size() - 1).controller;
+        removeAllExceptVisibleAndUnowned();
 
-            if (newTop != oldTop) {
+        if (newBackstack.size() > 0) {
+            List<RouterTransaction> reverseNewBackstack = new ArrayList<>(newBackstack);
+            Collections.reverse(reverseNewBackstack);
+            List<RouterTransaction> newVisibleTransactions = getVisibleTransactions(reverseNewBackstack.iterator());
+
+            boolean visibleTransactionsChanged = newVisibleTransactions.size() != oldVisibleTransactions.size();
+            if (!visibleTransactionsChanged) {
+                for (int i = 0; i < oldVisibleTransactions.size(); i++) {
+                    if (oldVisibleTransactions.get(i).controller != newVisibleTransactions.get(i).controller) {
+                        visibleTransactionsChanged = true;
+                        break;
+                    }
+                }
+            }
+
+            if (visibleTransactionsChanged) {
                 ControllerChangeHandler handler = changeHandler != null ? changeHandler : new SimpleSwapChangeHandler();
-                performControllerChange(newTop, oldTop, true, handler);
+
+                Controller rootController = oldVisibleTransactions.size() > 0 ? oldVisibleTransactions.get(0).controller : null;
+                performControllerChange(newVisibleTransactions.get(0).controller, rootController, true, handler);
+
+                for (int i = oldVisibleTransactions.size() - 1; i > 0; i--) {
+                    RouterTransaction transaction = oldVisibleTransactions.get(i);
+                    performControllerChange(null, transaction.controller, true, handler);
+                }
+
+                for (int i = 1; i < newVisibleTransactions.size(); i++) {
+                    RouterTransaction transaction = newVisibleTransactions.get(i);
+                    handler = transaction.pushChangeHandler() != null ? transaction.pushChangeHandler(): new SimpleSwapChangeHandler();
+                    performControllerChange(transaction.controller, newVisibleTransactions.get(i - 1).controller, true, handler);
+                }
             }
         }
 
@@ -316,7 +364,7 @@ public abstract class Router {
             transaction.onAttachedToRouter();
         }
 
-        backStack.setBackstack(backstack);
+        backstack.setBackstack(newBackstack);
     }
 
     /**
@@ -350,7 +398,7 @@ public abstract class Router {
      * Attaches this Router's existing backstack to its container if one exists.
      */
     public void rebindIfNeeded() {
-        Iterator<RouterTransaction> backstackIterator = backStack.reverseIterator();
+        Iterator<RouterTransaction> backstackIterator = backstack.reverseIterator();
         while (backstackIterator.hasNext()) {
             RouterTransaction transaction = backstackIterator.next();
 
@@ -368,7 +416,7 @@ public abstract class Router {
     }
 
     public final void onActivityStarted(Activity activity) {
-        for (RouterTransaction transaction : backStack) {
+        for (RouterTransaction transaction : backstack) {
             transaction.controller.activityStarted(activity);
 
             for (Router childRouter : transaction.controller.getChildRouters()) {
@@ -378,7 +426,7 @@ public abstract class Router {
     }
 
     public final void onActivityResumed(Activity activity) {
-        for (RouterTransaction transaction : backStack) {
+        for (RouterTransaction transaction : backstack) {
             transaction.controller.activityResumed(activity);
 
             for (Router childRouter : transaction.controller.getChildRouters()) {
@@ -388,7 +436,7 @@ public abstract class Router {
     }
 
     public final void onActivityPaused(Activity activity) {
-        for (RouterTransaction transaction : backStack) {
+        for (RouterTransaction transaction : backstack) {
             transaction.controller.activityPaused(activity);
 
             for (Router childRouter : transaction.controller.getChildRouters()) {
@@ -398,7 +446,7 @@ public abstract class Router {
     }
 
     public final void onActivityStopped(Activity activity) {
-        for (RouterTransaction transaction : backStack) {
+        for (RouterTransaction transaction : backstack) {
             transaction.controller.activityStopped(activity);
 
             for (Router childRouter : transaction.controller.getChildRouters()) {
@@ -411,7 +459,7 @@ public abstract class Router {
         prepareForContainerRemoval();
         changeListeners.clear();
 
-        for (RouterTransaction transaction : backStack) {
+        for (RouterTransaction transaction : backstack) {
             transaction.controller.activityDestroyed(activity.isChangingConfigurations());
 
             for (Router childRouter : transaction.controller.getChildRouters()) {
@@ -432,7 +480,8 @@ public abstract class Router {
     }
 
     public void prepareForHostDetach() {
-        for (RouterTransaction transaction : backStack) {
+        for (RouterTransaction transaction : backstack) {
+            ControllerChangeHandler.completePushImmediately(transaction.controller.getInstanceId());
             transaction.controller.prepareForHostDetach();
         }
     }
@@ -441,7 +490,7 @@ public abstract class Router {
         prepareForHostDetach();
 
         Bundle backstackState = new Bundle();
-        backStack.saveInstanceState(backstackState);
+        backstack.saveInstanceState(backstackState);
 
         outState.putParcelable(KEY_BACKSTACK, backstackState);
         outState.putBoolean(KEY_POPS_LAST_VIEW, popsLastView);
@@ -449,17 +498,17 @@ public abstract class Router {
 
     public void restoreInstanceState(Bundle savedInstanceState) {
         Bundle backstackBundle = savedInstanceState.getParcelable(KEY_BACKSTACK);
-        backStack.restoreInstanceState(backstackBundle);
+        backstack.restoreInstanceState(backstackBundle);
         popsLastView = savedInstanceState.getBoolean(KEY_POPS_LAST_VIEW);
 
-        Iterator<RouterTransaction> backstackIterator = backStack.reverseIterator();
+        Iterator<RouterTransaction> backstackIterator = backstack.reverseIterator();
         while (backstackIterator.hasNext()) {
             setControllerRouter(backstackIterator.next().controller);
         }
     }
 
     public final void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
-        for (RouterTransaction transaction : backStack) {
+        for (RouterTransaction transaction : backstack) {
             transaction.controller.createOptionsMenu(menu, inflater);
 
             for (Router childRouter : transaction.controller.getChildRouters()) {
@@ -469,7 +518,7 @@ public abstract class Router {
     }
 
     public final void onPrepareOptionsMenu(Menu menu) {
-        for (RouterTransaction transaction : backStack) {
+        for (RouterTransaction transaction : backstack) {
             transaction.controller.prepareOptionsMenu(menu);
 
             for (Router childRouter : transaction.controller.getChildRouters()) {
@@ -479,7 +528,7 @@ public abstract class Router {
     }
 
     public final boolean onOptionsItemSelected(MenuItem item) {
-        for (RouterTransaction transaction : backStack) {
+        for (RouterTransaction transaction : backstack) {
             if (transaction.controller.optionsItemSelected(item)) {
                 return true;
             }
@@ -494,8 +543,8 @@ public abstract class Router {
     }
 
     private void popToTransaction(@NonNull RouterTransaction transaction, ControllerChangeHandler changeHandler) {
-        RouterTransaction topTransaction = backStack.peek();
-        List<RouterTransaction> poppedTransactions = backStack.popTo(transaction);
+        RouterTransaction topTransaction = backstack.peek();
+        List<RouterTransaction> poppedTransactions = backstack.popTo(transaction);
         trackDestroyingControllers(poppedTransactions);
 
         if (poppedTransactions.size() > 0) {
@@ -503,7 +552,7 @@ public abstract class Router {
                 changeHandler = topTransaction.popChangeHandler();
             }
 
-            performControllerChange(backStack.peek().controller, topTransaction.controller, false, changeHandler);
+            performControllerChange(backstack.peek().controller, topTransaction.controller, false, changeHandler);
         }
     }
 
@@ -516,7 +565,7 @@ public abstract class Router {
     final List<Controller> getControllers() {
         List<Controller> controllers = new ArrayList<>();
 
-        Iterator<RouterTransaction> backstackIterator = backStack.reverseIterator();
+        Iterator<RouterTransaction> backstackIterator = backstack.reverseIterator();
         while (backstackIterator.hasNext()) {
             controllers.add(backstackIterator.next().controller);
         }
@@ -525,7 +574,7 @@ public abstract class Router {
     }
 
     public final Boolean handleRequestedPermission(@NonNull String permission) {
-        for (RouterTransaction transaction : backStack) {
+        for (RouterTransaction transaction : backstack) {
             if (transaction.controller.didRequestPermission(permission)) {
                 return transaction.controller.shouldShowRequestPermissionRationale(permission);
             }
@@ -557,7 +606,7 @@ public abstract class Router {
     private void performControllerChange(final Controller to, final Controller from, boolean isPush, @NonNull ControllerChangeHandler changeHandler) {
         if (to != null) {
             setControllerRouter(to);
-        } else if (backStack.size() == 0 && !popsLastView) {
+        } 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.
             changeHandler = new NoOpControllerChangeHandler();
@@ -567,7 +616,7 @@ public abstract class Router {
     }
 
     void pushToBackstack(@NonNull RouterTransaction entry) {
-        backStack.push(entry);
+        backstack.push(entry);
     }
 
     private void trackDestroyingController(RouterTransaction transaction) {
@@ -589,13 +638,13 @@ public abstract class Router {
         }
     }
 
-    private void removeAllExceptTopAndUnowned() {
+    private void removeAllExceptVisibleAndUnowned() {
         List<View> views = new ArrayList<>();
 
-        RouterTransaction topTransaction = backStack.peek();
-        final View topView = topTransaction != null ? topTransaction.controller.getView() : null;
-        if (topView != null) {
-            views.add(topView);
+        for (RouterTransaction transaction : getVisibleTransactions(backstack.iterator())) {
+            if (transaction.controller.getView() != null) {
+                views.add(transaction.controller.getView());
+            }
         }
 
         for (Router router : getSiblingRouters()) {
@@ -625,6 +674,21 @@ public abstract class Router {
         }
     }
 
+    private List<RouterTransaction> getVisibleTransactions(Iterator<RouterTransaction> backstackIterator) {
+        List<RouterTransaction> transactions = new ArrayList<>();
+        while (backstackIterator.hasNext()) {
+            RouterTransaction transaction = backstackIterator.next();
+            transactions.add(transaction);
+
+            if (transaction.pushChangeHandler() == null || transaction.pushChangeHandler().removesFromViewOnPush()) {
+                break;
+            }
+        }
+
+        Collections.reverse(transactions);
+        return transactions;
+    }
+
     void setControllerRouter(Controller controller) {
         controller.setRouter(this);
     }
@@ -638,4 +702,5 @@ public abstract class Router {
     abstract void requestPermissions(String instanceId, String[] permissions, int requestCode);
     abstract boolean hasHost();
     abstract List<Router> getSiblingRouters();
+    abstract Router getRootRouter();
 }

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

@@ -24,6 +24,7 @@ public abstract class AnimatorChangeHandler extends ControllerChangeHandler {
     private long animationDuration;
     private boolean removesFromViewOnPush;
     private boolean canceled;
+    private boolean needsImmediateCompletion;
     private Animator animator;
 
     public AnimatorChangeHandler() {
@@ -67,10 +68,21 @@ public abstract class AnimatorChangeHandler extends ControllerChangeHandler {
         }
     }
 
+    @Override
+    public void completeImmediately() {
+        super.completeImmediately();
+
+        needsImmediateCompletion = true;
+        if (animator != null) {
+            animator.cancel();
+        }
+    }
+
     public long getAnimationDuration() {
         return animationDuration;
     }
 
+    @Override
     public boolean removesFromViewOnPush() {
         return removesFromViewOnPush;
     }
@@ -99,7 +111,7 @@ public abstract class AnimatorChangeHandler extends ControllerChangeHandler {
         if (addingToView) {
             if (isPush || from == null) {
                 container.addView(to);
-            } else {
+            } else if (to.getParent() == null) {
                 container.addView(to, container.indexOfChild(from));
             }
 
@@ -139,7 +151,13 @@ 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);
+                }
+
                 changeListener.onChangeCompleted();
+                animator.removeListener(this);
+                animator = null;
             }
 
             @Override
@@ -149,12 +167,16 @@ public abstract class AnimatorChangeHandler extends ControllerChangeHandler {
                 }
 
                 changeListener.onChangeCompleted();
+                animator.removeListener(this);
 
                 if (isPush && from != null) {
                     resetFromView(from);
                 }
+
+                animator = null;
             }
         });
+
         animator.start();
     }
 

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

@@ -5,6 +5,7 @@ import android.support.annotation.NonNull;
 import android.view.View;
 import android.view.ViewGroup;
 
+import com.bluelinelabs.conductor.Controller;
 import com.bluelinelabs.conductor.ControllerChangeHandler;
 
 /**
@@ -16,6 +17,8 @@ public class SimpleSwapChangeHandler extends ControllerChangeHandler {
 
     private boolean removesFromViewOnPush;
 
+    private boolean canceled;
+
     public SimpleSwapChangeHandler() {
         this(true);
     }
@@ -37,16 +40,29 @@ public class SimpleSwapChangeHandler extends ControllerChangeHandler {
     }
 
     @Override
-    public void performChange(@NonNull ViewGroup container, View from, View to, boolean isPush, @NonNull final ControllerChangeCompletedListener changeListener) {
-        if (from != null && (!isPush || removesFromViewOnPush)) {
-            container.removeView(from);
-        }
+    public void onAbortPush(@NonNull ControllerChangeHandler newHandler, Controller newTop) {
+        super.onAbortPush(newHandler, newTop);
 
-        if (to != null && to.getParent() == null) {
-            container.addView(to);
+        canceled = true;
+    }
+
+    @Override
+    public void performChange(@NonNull ViewGroup container, View from, View to, boolean isPush, @NonNull final ControllerChangeCompletedListener changeListener) {
+        if (!canceled) {
+            if (from != null && (!isPush || removesFromViewOnPush)) {
+                container.removeView(from);
+            }
+
+            if (to != null && to.getParent() == null) {
+                container.addView(to);
+            }
         }
 
         changeListener.onChangeCompleted();
     }
 
-}
+    @Override
+    public boolean removesFromViewOnPush() {
+        return removesFromViewOnPush;
+    }
+}

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

@@ -76,4 +76,8 @@ public abstract class TransitionChangeHandler extends ControllerChangeHandler {
         }
     }
 
+    @Override
+    public final boolean removesFromViewOnPush() {
+        return true;
+    }
 }

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

@@ -77,4 +77,12 @@ public class TransitionChangeHandlerCompat extends ControllerChangeHandler {
         fallbackChangeHandler.restoreFromBundle(bundle.getBundle(KEY_FALLBACK_HANDLER_STATE));
     }
 
+    @Override
+    public boolean removesFromViewOnPush() {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+            return transitionChangeHandler.removesFromViewOnPush();
+        } else {
+            return fallbackChangeHandler.removesFromViewOnPush();
+        }
+    }
 }

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

@@ -29,6 +29,7 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
 
     private static final String KEY_PERMISSION_REQUEST_CODES = "LifecycleHandler.permissionRequests";
     private static final String KEY_ACTIVITY_REQUEST_CODES = "LifecycleHandler.activityRequests";
+    private static final String KEY_ROUTER_STATE_PREFIX = "LifecycleHandler.routerState";
 
     private Activity activity;
     private boolean hasRegisteredCallbacks;
@@ -69,7 +70,10 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
             router.setHost(this, container);
 
             if (savedInstanceState != null) {
-                router.restoreInstanceState(savedInstanceState);
+                Bundle routerSavedState = savedInstanceState.getBundle(KEY_ROUTER_STATE_PREFIX + router.getContainerId());
+                if (routerSavedState != null) {
+                    router.restoreInstanceState(routerSavedState);
+                }
             }
             routerMap.put(getRouterHashKey(container), router);
         } else {
@@ -303,7 +307,9 @@ public class LifecycleHandler extends Fragment implements ActivityLifecycleCallb
     public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
         if (this.activity == activity) {
             for (Router router : routerMap.values()) {
-                router.saveInstanceState(outState);
+                Bundle bundle = new Bundle();
+                router.saveInstanceState(bundle);
+                outState.putBundle(KEY_ROUTER_STATE_PREFIX + router.getContainerId(), bundle);
             }
         }
     }

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

@@ -8,7 +8,7 @@ import android.view.ViewGroup;
 import android.widget.FrameLayout;
 
 import com.bluelinelabs.conductor.Controller.LifecycleListener;
-import com.bluelinelabs.conductor.ControllerChangeHandler.ControllerChangeCompletedListener;
+import com.bluelinelabs.conductor.MockChangeHandler.ChangeHandlerListener;
 
 import org.junit.Assert;
 import org.junit.Before;
@@ -377,22 +377,8 @@ public class ControllerLifecycleTests {
         });
 
         router.pushController(RouterTransaction.with(testController)
-                .pushChangeHandler(new ChangeHandler(new ChangeHandlerListener() {
-                    @Override
-                    public void performChange(@NonNull ViewGroup container, View from, View to, boolean isPush, @NonNull ControllerChangeCompletedListener changeListener) {
-                        container.addView(to);
-                        ViewUtils.setAttached(to, true);
-                        changeListener.onChangeCompleted();
-                    }
-                }))
-                .popChangeHandler(new ChangeHandler(new ChangeHandlerListener() {
-                    @Override
-                    public void performChange(@NonNull ViewGroup container, View from, View to, boolean isPush, @NonNull ControllerChangeCompletedListener changeListener) {
-                        container.removeView(from);
-                        ViewUtils.setAttached(from, false);
-                        changeListener.onChangeCompleted();
-                    }
-                })));
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
 
         router.popController(testController);
 
@@ -407,14 +393,7 @@ public class ControllerLifecycleTests {
     public void testChildLifecycle() {
         Controller parent = new TestController();
         router.pushController(RouterTransaction.with(parent)
-                .pushChangeHandler(new ChangeHandler(new ChangeHandlerListener() {
-                    @Override
-                    public void performChange(@NonNull ViewGroup container, View from, View to, boolean isPush, @NonNull ControllerChangeCompletedListener changeListener) {
-                        container.addView(to);
-                        ViewUtils.setAttached(to, true);
-                        changeListener.onChangeCompleted();
-                    }
-                })));
+                .pushChangeHandler(new MockChangeHandler()));
 
         TestController child = new TestController();
         attachLifecycleListener(child);
@@ -440,22 +419,8 @@ public class ControllerLifecycleTests {
     public void testChildLifecycle2() {
         Controller parent = new TestController();
         router.pushController(RouterTransaction.with(parent)
-                .pushChangeHandler(new ChangeHandler(new ChangeHandlerListener() {
-                    @Override
-                    public void performChange(@NonNull ViewGroup container, View from, View to, boolean isPush, @NonNull ControllerChangeCompletedListener changeListener) {
-                        container.addView(to);
-                        ViewUtils.setAttached(to, true);
-                        changeListener.onChangeCompleted();
-                    }
-                }))
-                .popChangeHandler(new ChangeHandler(new ChangeHandlerListener() {
-                    @Override
-                    public void performChange(@NonNull ViewGroup container, View from, View to, boolean isPush, @NonNull ControllerChangeCompletedListener changeListener) {
-                        container.removeView(from);
-                        ViewUtils.setAttached(from, false);
-                        changeListener.onChangeCompleted();
-                    }
-                })));
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
 
         TestController child = new TestController();
         attachLifecycleListener(child);
@@ -477,44 +442,47 @@ public class ControllerLifecycleTests {
         assertCalls(expectedCallState, child);
     }
 
-    private ChangeHandler getPushHandler(final CallState expectedCallState, final TestController controller) {
-        return new ChangeHandler(new ChangeHandlerListener() {
+    private MockChangeHandler getPushHandler(final CallState expectedCallState, final TestController controller) {
+        return new MockChangeHandler(new ChangeHandlerListener() {
             @Override
-            public void performChange(@NonNull ViewGroup container, View from, View to, boolean isPush, @NonNull ControllerChangeCompletedListener changeListener) {
+            void willStartChange() {
                 expectedCallState.changeStartCalls++;
                 expectedCallState.createViewCalls++;
                 assertCalls(expectedCallState, controller);
+            }
 
-                container.addView(to);
-                ViewUtils.setAttached(to, true);
-
+            @Override
+            void didAttachOrDetach() {
                 expectedCallState.attachCalls++;
                 assertCalls(expectedCallState, controller);
+            }
 
-                changeListener.onChangeCompleted();
-
+            @Override
+            void didEndChange() {
                 expectedCallState.changeEndCalls++;
                 assertCalls(expectedCallState, controller);
             }
         });
     }
 
-    private ChangeHandler getPopHandler(final CallState expectedCallState, final TestController controller) {
-        return new ChangeHandler(new ChangeHandlerListener() {
+    private MockChangeHandler getPopHandler(final CallState expectedCallState, final TestController controller) {
+        return new MockChangeHandler(new ChangeHandlerListener() {
             @Override
-            public void performChange(@NonNull ViewGroup container, View from, View to, boolean isPush, @NonNull ControllerChangeCompletedListener changeListener) {
+            void willStartChange() {
                 expectedCallState.changeStartCalls++;
                 assertCalls(expectedCallState, controller);
-                container.removeView(from);
-                ViewUtils.setAttached(from, false);
+            }
 
+            @Override
+            void didAttachOrDetach() {
                 expectedCallState.destroyViewCalls++;
                 expectedCallState.detachCalls++;
                 expectedCallState.destroyCalls++;
                 assertCalls(expectedCallState, controller);
+            }
 
-                changeListener.onChangeCompleted();
-
+            @Override
+            void didEndChange() {
                 expectedCallState.changeEndCalls++;
                 assertCalls(expectedCallState, controller);
             }
@@ -585,24 +553,4 @@ public class ControllerLifecycleTests {
         });
     }
 
-    interface ChangeHandlerListener {
-        void performChange(@NonNull ViewGroup container, View from, View to, boolean isPush, @NonNull ControllerChangeCompletedListener changeListener);
-    }
-
-    public static class ChangeHandler extends ControllerChangeHandler {
-
-        private ChangeHandlerListener listener;
-
-        public ChangeHandler() { }
-
-        public ChangeHandler(ChangeHandlerListener listener) {
-            this.listener = listener;
-        }
-
-        @Override
-        public void performChange(@NonNull ViewGroup container, View from, View to, boolean isPush, @NonNull ControllerChangeCompletedListener changeListener) {
-            listener.performChange(container, from, to, isPush, changeListener);
-        }
-    }
-
 }

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

@@ -0,0 +1,57 @@
+package com.bluelinelabs.conductor;
+
+
+import android.support.annotation.NonNull;
+import android.view.View;
+import android.view.ViewGroup;
+
+public class MockChangeHandler extends ControllerChangeHandler {
+
+    static class ChangeHandlerListener {
+        void willStartChange() { }
+        void didAttachOrDetach() { }
+        void didEndChange() { }
+    }
+
+    final ChangeHandlerListener listener;
+
+    public MockChangeHandler() {
+        this(new ChangeHandlerListener() { });
+    }
+
+    public MockChangeHandler(@NonNull ChangeHandlerListener listener) {
+        this.listener = listener;
+    }
+
+    @Override
+    public void performChange(@NonNull ViewGroup container, View from, View to, boolean isPush, @NonNull ControllerChangeCompletedListener changeListener) {
+        listener.willStartChange();
+
+        if (isPush) {
+            container.addView(to);
+            ViewUtils.setAttached(to, true);
+
+            listener.didAttachOrDetach();
+
+            if (from != null) {
+                container.removeView(from);
+                ViewUtils.setAttached(from, false);
+            }
+        } else {
+            container.removeView(from);
+            ViewUtils.setAttached(from, false);
+
+            listener.didAttachOrDetach();
+
+            if (to != null) {
+                container.addView(to);
+                ViewUtils.setAttached(to, true);
+            }
+
+        }
+
+        changeListener.onChangeCompleted();
+        listener.didEndChange();
+    }
+
+}

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

@@ -2,13 +2,9 @@ package com.bluelinelabs.conductor;
 
 import android.os.Bundle;
 import android.support.annotation.IdRes;
-import android.support.annotation.NonNull;
-import android.view.View;
 import android.view.ViewGroup;
 import android.widget.FrameLayout;
 
-import com.bluelinelabs.conductor.ControllerChangeHandler.ControllerChangeCompletedListener;
-
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
@@ -49,8 +45,8 @@ public class ReattachCaseTests {
         final TestController controllerB = new TestController();
 
         router.pushController(RouterTransaction.with(controllerA)
-            .pushChangeHandler(getPushHandler())
-            .popChangeHandler(getPopHandler()));
+            .pushChangeHandler(new MockChangeHandler())
+            .popChangeHandler(new MockChangeHandler()));
 
         Assert.assertTrue(controllerA.isAttached());
         Assert.assertFalse(controllerB.isAttached());
@@ -61,8 +57,8 @@ public class ReattachCaseTests {
         Assert.assertFalse(controllerB.isAttached());
 
         router.pushController(RouterTransaction.with(controllerB)
-                .pushChangeHandler(getPushHandler())
-                .popChangeHandler(getPopHandler()));
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
 
         Assert.assertFalse(controllerA.isAttached());
         Assert.assertTrue(controllerB.isAttached());
@@ -80,13 +76,13 @@ public class ReattachCaseTests {
         final TestController controllerB = new TestController();
 
         router.pushController(RouterTransaction.with(controllerA)
-                .pushChangeHandler(getPushHandler())
-                .popChangeHandler(getPopHandler()));
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
 
         Router childRouter = controllerA.getChildRouter((ViewGroup)controllerA.getView().findViewById(TestController.VIEW_ID), null);
         childRouter.pushController(RouterTransaction.with(childController)
-            .pushChangeHandler(getPushHandler())
-            .popChangeHandler(getPopHandler()));
+            .pushChangeHandler(new MockChangeHandler())
+            .popChangeHandler(new MockChangeHandler()));
 
         Assert.assertTrue(controllerA.isAttached());
         Assert.assertTrue(childController.isAttached());
@@ -99,8 +95,8 @@ public class ReattachCaseTests {
         Assert.assertFalse(controllerB.isAttached());
 
         router.pushController(RouterTransaction.with(controllerB)
-                .pushChangeHandler(getPushHandler())
-                .popChangeHandler(getPopHandler()));
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
 
         Assert.assertFalse(controllerA.isAttached());
         Assert.assertFalse(childController.isAttached());
@@ -121,22 +117,22 @@ public class ReattachCaseTests {
         final TestController childController = new TestController();
 
         router.pushController(RouterTransaction.with(controllerA)
-                .pushChangeHandler(getPushHandler())
-                .popChangeHandler(getPopHandler()));
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
 
         Assert.assertTrue(controllerA.isAttached());
         Assert.assertFalse(controllerB.isAttached());
         Assert.assertFalse(childController.isAttached());
 
         router.pushController(RouterTransaction.with(controllerB)
-                .pushChangeHandler(getPushHandler())
-                .popChangeHandler(getPopHandler()));
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
 
         Router childRouter = controllerB.getChildRouter((ViewGroup)controllerB.getView().findViewById(TestController.VIEW_ID), null);
         childRouter.setPopsLastView(true);
         childRouter.pushController(RouterTransaction.with(childController)
-                .pushChangeHandler(getPushHandler())
-                .popChangeHandler(getPopHandler()));
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
 
         Assert.assertFalse(controllerA.isAttached());
         Assert.assertTrue(controllerB.isAttached());
@@ -169,22 +165,22 @@ public class ReattachCaseTests {
         TestController childController = new TestController();
 
         router.pushController(RouterTransaction.with(controllerA)
-                .pushChangeHandler(getPushHandler())
-                .popChangeHandler(getPopHandler()));
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
 
         Assert.assertTrue(controllerA.isAttached());
         Assert.assertFalse(controllerB.isAttached());
         Assert.assertFalse(childController.isAttached());
 
         router.pushController(RouterTransaction.with(controllerB)
-                .pushChangeHandler(getPushHandler())
-                .popChangeHandler(getPopHandler()));
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
 
         Router childRouter = controllerB.getChildRouter((ViewGroup)controllerB.getView().findViewById(TestController.VIEW_ID), null);
         childRouter.setPopsLastView(true);
         childRouter.pushController(RouterTransaction.with(childController)
-                .pushChangeHandler(getPushHandler())
-                .popChangeHandler(getPopHandler()));
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
 
         Assert.assertFalse(controllerA.isAttached());
         Assert.assertTrue(controllerB.isAttached());
@@ -198,8 +194,8 @@ public class ReattachCaseTests {
 
         childController = new TestController();
         childRouter.pushController(RouterTransaction.with(childController)
-                .pushChangeHandler(getPushHandler())
-                .popChangeHandler(getPopHandler()));
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
 
         Assert.assertFalse(controllerA.isAttached());
         Assert.assertTrue(controllerB.isAttached());
@@ -215,8 +211,8 @@ public class ReattachCaseTests {
 
         childController = new TestController();
         childRouter.pushController(RouterTransaction.with(childController)
-                .pushChangeHandler(getPushHandler())
-                .popChangeHandler(getPopHandler()));
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
 
         Assert.assertFalse(controllerA.isAttached());
         Assert.assertTrue(controllerB.isAttached());
@@ -250,57 +246,4 @@ public class ReattachCaseTests {
         router.rebindIfNeeded();
     }
 
-    private ChangeHandler getPushHandler() {
-        return new ChangeHandler(new ChangeHandlerListener() {
-            @Override
-            public void performChange(@NonNull ViewGroup container, View from, View to, @NonNull ControllerChangeCompletedListener changeListener) {
-                container.addView(to);
-                ViewUtils.setAttached(to, true);
-
-                if (from != null) {
-                    container.removeView(from);
-                    ViewUtils.setAttached(from, false);
-                }
-
-                changeListener.onChangeCompleted();
-            }
-        });
-    }
-
-    private ChangeHandler getPopHandler() {
-        return new ChangeHandler(new ChangeHandlerListener() {
-            @Override
-            public void performChange(@NonNull ViewGroup container, View from, View to, @NonNull ControllerChangeCompletedListener changeListener) {
-                container.removeView(from);
-                ViewUtils.setAttached(from, false);
-                changeListener.onChangeCompleted();
-
-                if (to != null) {
-                    container.addView(to);
-                    ViewUtils.setAttached(to, true);
-                }
-            }
-        });
-    }
-
-    interface ChangeHandlerListener {
-        void performChange(@NonNull ViewGroup container, View from, View to, @NonNull ControllerChangeCompletedListener changeListener);
-    }
-
-    public static class ChangeHandler extends ControllerChangeHandler {
-
-        private ChangeHandlerListener listener;
-
-        public ChangeHandler() { }
-
-        public ChangeHandler(ChangeHandlerListener listener) {
-            this.listener = listener;
-        }
-
-        @Override
-        public void performChange(@NonNull ViewGroup container, View from, View to, boolean isPush, @NonNull ControllerChangeCompletedListener changeListener) {
-            listener.performChange(container, from, to, changeListener);
-        }
-    }
-
 }

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

@@ -0,0 +1,110 @@
+package com.bluelinelabs.conductor;
+
+import android.os.Bundle;
+import android.support.annotation.IdRes;
+import android.view.ViewGroup;
+import android.widget.FrameLayout;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.Robolectric;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.annotation.Config;
+import org.robolectric.util.ActivityController;
+
+@RunWith(RobolectricTestRunner.class)
+@Config(manifest = Config.NONE)
+public class TargetControllerTests {
+
+    private ActivityController<TestActivity> activityController;
+    private Router router;
+
+    public void createActivityController(Bundle savedInstanceState) {
+        activityController = Robolectric.buildActivity(TestActivity.class).create(savedInstanceState).start();
+
+        @IdRes int containerId = 4;
+        FrameLayout routerContainer = new FrameLayout(activityController.get());
+        routerContainer.setId(containerId);
+
+        router = Conductor.attachRouter(activityController.get(), routerContainer, savedInstanceState);
+        if (!router.hasRootController()) {
+            router.setRoot(RouterTransaction.with(new TestController()));
+        }
+    }
+
+    @Before
+    public void setup() {
+        createActivityController(null);
+    }
+
+    @Test
+    public void testSiblingTarget() {
+        final TestController controllerA = new TestController();
+        final TestController controllerB = new TestController();
+
+        Assert.assertNull(controllerA.getTargetController());
+        Assert.assertNull(controllerB.getTargetController());
+
+        router.pushController(RouterTransaction.with(controllerA)
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
+
+        controllerB.setTargetController(controllerA);
+
+        router.pushController(RouterTransaction.with(controllerB)
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
+
+        Assert.assertNull(controllerA.getTargetController());
+        Assert.assertEquals(controllerA, controllerB.getTargetController());
+    }
+
+    @Test
+    public void testParentChildTarget() {
+        final TestController controllerA = new TestController();
+        final TestController controllerB = new TestController();
+
+        Assert.assertNull(controllerA.getTargetController());
+        Assert.assertNull(controllerB.getTargetController());
+
+        router.pushController(RouterTransaction.with(controllerA)
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
+
+        controllerB.setTargetController(controllerA);
+
+        Router childRouter = controllerA.getChildRouter((ViewGroup)controllerA.getView().findViewById(TestController.VIEW_ID), null);
+        childRouter.pushController(RouterTransaction.with(controllerB)
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
+
+        Assert.assertNull(controllerA.getTargetController());
+        Assert.assertEquals(controllerA, controllerB.getTargetController());
+    }
+
+    @Test
+    public void testChildParentTarget() {
+        final TestController controllerA = new TestController();
+        final TestController controllerB = new TestController();
+
+        Assert.assertNull(controllerA.getTargetController());
+        Assert.assertNull(controllerB.getTargetController());
+
+        router.pushController(RouterTransaction.with(controllerA)
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
+
+        controllerA.setTargetController(controllerB);
+
+        Router childRouter = controllerA.getChildRouter((ViewGroup)controllerA.getView().findViewById(TestController.VIEW_ID), null);
+        childRouter.pushController(RouterTransaction.with(controllerB)
+                .pushChangeHandler(new MockChangeHandler())
+                .popChangeHandler(new MockChangeHandler()));
+
+        Assert.assertNull(controllerB.getTargetController());
+        Assert.assertEquals(controllerB, controllerA.getTargetController());
+    }
+
+}

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

@@ -12,22 +12,20 @@ import com.bluelinelabs.conductor.demo.controllers.HomeController;
 
 import butterknife.BindView;
 import butterknife.ButterKnife;
-import butterknife.Unbinder;
 
-public class MainActivity extends AppCompatActivity implements ActionBarProvider {
+public final class MainActivity extends AppCompatActivity implements ActionBarProvider {
 
     @BindView(R.id.toolbar) Toolbar toolbar;
     @BindView(R.id.controller_container) ViewGroup container;
 
     private Router router;
-    private Unbinder unbinder;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
         setContentView(R.layout.activity_main);
-        unbinder = ButterKnife.bind(this);
+        ButterKnife.bind(this);
 
         setSupportActionBar(toolbar);
 
@@ -44,10 +42,4 @@ public class MainActivity extends AppCompatActivity implements ActionBarProvider
         }
     }
 
-    @Override
-    protected void onDestroy() {
-        super.onDestroy();
-        unbinder.unbind();
-    }
-
 }

demo/src/main/java/com/bluelinelabs/conductor/demo/controllers/base/ButterKnifeController.java

@@ -37,6 +37,7 @@ public abstract class ButterKnifeController extends RxController {
     protected void onDestroyView(View view) {
         super.onDestroyView(view);
         unbinder.unbind();
+        unbinder = null;
     }
 
 }

demo/src/main/java/com/bluelinelabs/conductor/demo/controllers/base/RefWatchingController.java

@@ -1,7 +1,10 @@
 package com.bluelinelabs.conductor.demo.controllers.base;
 
 import android.os.Bundle;
+import android.support.annotation.NonNull;
 
+import com.bluelinelabs.conductor.ControllerChangeHandler;
+import com.bluelinelabs.conductor.ControllerChangeType;
 import com.bluelinelabs.conductor.demo.DemoApplication;
 
 public abstract class RefWatchingController extends ButterKnifeController {
@@ -11,10 +14,24 @@ public abstract class RefWatchingController extends ButterKnifeController {
         super(args);
     }
 
+    private boolean hasExited;
+
     @Override
     public void onDestroy() {
         super.onDestroy();
-        DemoApplication.refWatcher.watch(this);
+
+        if (hasExited) {
+            DemoApplication.refWatcher.watch(this);
+        }
     }
 
+    @Override
+    protected void onChangeEnded(@NonNull ControllerChangeHandler changeHandler, @NonNull ControllerChangeType changeType) {
+        super.onChangeEnded(changeHandler, changeType);
+
+        hasExited = !changeType.isEnter;
+        if (isDestroyed()) {
+            DemoApplication.refWatcher.watch(this);
+        }
+    }
 }

dependencies.gradle

@@ -14,8 +14,8 @@ ext {
 
     picasso = 'com.squareup.picasso:picasso:2.5.2'
 
-    leakCanary = 'com.squareup.leakcanary:leakcanary-android:1.4-beta2'
-    leakCanaryNoOp = 'com.squareup.leakcanary:leakcanary-android-no-op:1.4-beta2'
+    leakCanary = 'com.squareup.leakcanary:leakcanary-android:1.4'
+    leakCanaryNoOp = 'com.squareup.leakcanary:leakcanary-android-no-op:1.4'
 
     rxJava = 'io.reactivex:rxjava:1.1.0'
     rxAndroid = 'io.reactivex:rxandroid:1.1.0'

gradle.properties

@@ -1,4 +1,4 @@
-VERSION_NAME=2.0.2-SNAPSHOT
+VERSION_NAME=2.0.3-SNAPSHOT
 VERSION_CODE=2
 GROUP=com.bluelinelabs
 

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Tue Jan 19 22:43:12 CST 2016
+#Mon Sep 05 10:45:48 CDT 2016
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.10-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.14.1-all.zip