Add doc with edge-to-edge info and instructions

app/src/main/java/com/emanuelef/remote_capture/activities/AboutActivity.java

@@ -14,7 +14,7 @@
  * You should have received a copy of the GNU General Public License
  * along with PCAPdroid.  If not, see <http://www.gnu.org/licenses/>.
  *
- * Copyright 2020-24 - Emanuele Faranda
+ * Copyright 2020-25 - Emanuele Faranda
  */
 
 package com.emanuelef.remote_capture.activities;

app/src/main/res/layout/about_activity.xml

@@ -71,7 +71,7 @@
                     android:layout_height="wrap_content"
                     android:layout_marginTop="20dp"
                     android:autoLink="email"
-                    android:text="Copyright (C) 2020-24 - Emanuele Faranda black.silver@hotmail.it" />
+                    android:text="Copyright (C) 2020-25 - Emanuele Faranda black.silver@hotmail.it" />
 
                 <TextView
                     android:id="@+id/app_license"

docs/edge-to-edge.md

@@ -0,0 +1,73 @@
+# Edge-to-edge support in PCAPdroid
+
+This document gives a brief introduction to edge-to-edge and contains the guidelines on how to implement proper edge-to-edge support for new views and activities.
+
+See https://medium.com/androiddevelopers/insets-handling-tips-for-android-15s-edge-to-edge-enforcement-872774e8839b for a detailed description.
+
+- Android 35 forces apps to be edge-to-edge
+- It's temporary possible to opt out by applying a custom style:
+
+```
+<!-- In values-v35.xml -->
+<resources>
+    <!-- TODO: Remove once activities handle insets. -->
+    <style name="OptOutEdgeToEdgeEnforcement">
+        <item name="android:windowOptOutEdgeToEdgeEnforcement">true</item>
+    </style>
+</resources>
+```
+
+- Implementing edge-to-edge support requires a lot of efforts, in particular to handle all the possible cases for insets
+- Moreover, there can be issues which only appear on older Android versions (e.g. Android 9, see adbc33afe55f2c1795d250707fc3f29aadacdbb0)
+- When edge-to-edge support is enabled, it breaks the ability to select a custom theme, see 5f50ae30c1e8b4f2ce73cb684066d12fb0d65b0a
+
+# How it works
+
+- inset types:
+  - WindowInsetsCompat.Type.statusBars: the status bar, which is the one with icons and wall clock
+  - WindowInsetsCompat.Type.systemBars: any system bar, e.g. 3-buttons navigation bar
+  - WindowInsetsCompat.Type.displayCutout: cutouts in the displays, e.g. camera holes
+  - WindowInsetsCompat.Type.ime: virtual keyboard. Handling of this inset is not usually required, but it allows to get a better behavior on IME open
+    - e.g. to resize the ReciclerView to make all the items visible on screen
+
+- insets handling works hierarchically:
+  - the top views first get a chance to handle the insets
+  - if the top views don't consume the insets, they get propagated to the children
+  - it's unclear how it affects siblings, but it does, see issues on Android 9 adbc33afe55f2c1795d250707fc3f29aadacdbb0
+
+- insets can either be handled via:
+  - ViewCompat.setOnApplyWindowInsetsListener
+    - you can choose to consume or not the insets
+    - makes it possible to implement edge-to-edge
+  - fitsSystemWindows="true"
+    - it always *consumes* all the insets
+    - it just adds margins, without proper edge-to-edge support. Normally it should not be used
+
+- ViewPager2 does not handle insets dispatching properly
+  - https://issuetracker.google.com/issues/145617093#comment10
+  - to fix it, it's necessary to dispatch the insets manually on tab change: ViewCompat.dispatchApplyWindowInsets
+    - see Utils.fixViewPager2Insets
+
+# Guidelines
+
+- To enable proper edge-to-edge support, in particular on older platforms, when creating an Activity be sure to either:
+  - just inherit from BaseActivity, which internally calls Utils.enableEdgeToEdge and handles the insets for the toolbar (preferred approach)
+  - call Utils.enableEdgeToEdge manually in onCreate, before super.onCreate
+
+- The activity layout must use AppBarLayout and Toolbar (with id `toolbar`) in a CoordinatorLayout. See how it is done for other activities (e.g. about_activity.xml)
+  - this makes proper space for the toolbar
+  - when possible, reuse `fragment_activity.xml`, for simple activities made of just 1 fragment
+  - for tab-based activities, either use `tab_activity.xml` or `tab_activity_fixed.xml`. In the latter case, be sure to call `Utils.fixScrollableTabLayoutInsets`
+  - the toolbar needs some top insets handling; if you inherit from BaseActivity, this is already implemented
+
+- When using ViewPager2, be sure to call Utils.fixViewPager2Insets to properly dispatch insets to sub-views
+- For ReciclerViews, use EmptyRecyclerView when possible, which already handles insets, IME (virtual keyboard), uses setClipToPadding(false) for edge-to-edge support
+- For ListViews, use Utils.fixListviewInsetsBottom for edge-to-edge support
+
+- New activity testing:
+  - test with 3-buttons bottom navbar. This can be enabled from the Android settings
+  - to properly test scrolling behavior, ensure to populate the views
+  - test horizontal insets with rotated device
+  - test with IME open/closed in views that use it
+  - test on the newest Android version
+  - test on Android 9 or lower, as some bugs are only visible there (e.g. adbc33afe55f2c1795d250707fc3f29aadacdbb0)