Proper support for Android 15 edge-to-edge (#848)

The keyboard background now extends under the system bars and display
cutout on Android 15 but the keys do not.

The back and IME switching buttons that appear in the navigation bar require
special care to not overlap with the keyboard.

The launcher and settings activity are also fixed.

AndroidManifest.xml

@@ -10,11 +10,13 @@
       </intent-filter>
       <meta-data android:name="android.view.im" android:resource="@xml/method"/>
     </service>
-    <activity android:name="juloo.keyboard2.SettingsActivity" android:icon="@mipmap/ic_launcher" android:label="@string/settings_activity_label" android:theme="@style/appTheme" android:exported="true" android:directBootAware="true">
+
+    <activity android:name="juloo.keyboard2.SettingsActivity" android:icon="@mipmap/ic_launcher" android:label="@string/settings_activity_label" android:theme="@style/settingsTheme" android:exported="true" android:directBootAware="true">
       <intent-filter>
         <action android:name="android.intent.action.MAIN"/>
       </intent-filter>
     </activity>
+
     <activity android:name="juloo.keyboard2.LauncherActivity" android:icon="@mipmap/ic_launcher" android:theme="@style/appTheme" android:exported="true" android:directBootAware="true">
       <intent-filter>
         <action android:name="android.intent.action.MAIN"/>

res/layout/launcher_activity.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<ScrollView xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:fillViewport="true">
+<ScrollView xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:fillViewport="true" android:fitsSystemWindows="true">
   <LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical">
     <TextView style="@style/paragraph" android:text="@string/launcher_description"/>
     <Button style="@style/paragraph" android:text="@string/launcher_button_imesettings" android:onClick="launch_imesettings" android:layout_width="wrap_content"/>

res/values/styles.xml

@@ -80,4 +80,9 @@
     <item name="android:orientation">horizontal</item>
   </style>
   <style name="appTheme" parent="@android:style/Theme.DeviceDefault.DayNight"/>
+  <style name="settingsTheme" parent="appTheme">
+    <!-- Setting this in the activity theme so it propagate to nested
+         preference screens. -->
+    <item name="android:fitsSystemWindows">true</item>
+  </style>
 </resources>

res/values/values.xml

@@ -6,5 +6,9 @@
   <dimen name="emoji_text_size">28dp</dimen>
   <dimen name="clipboard_view_height">300dp</dimen>
   <dimen name="pref_button_size">28dp</dimen>
-  <bool name="debug_logs">false</bool> <!-- Will be overwritten automatically by Gradle for the debug build variant -->
+  <!-- Margin needed to accomodate the gesture nav bar on Android 15. Found in
+  [core/res/res/values/dimens.xml]. -->
+  <dimen name="bottom_inset_min">48dp</dimen>
+  <!-- Will be overwritten automatically by Gradle for the debug build variant -->
+  <bool name="debug_logs">false</bool>
 </resources>

srcs/juloo.keyboard2/Config.java

@@ -84,6 +84,7 @@ public final class Config
       [get_current_layout()] and [set_current_layout()]. */
   int current_layout_portrait;
   int current_layout_landscape;
+  public int bottomInsetMin;
 
   private Config(SharedPreferences prefs, Resources res, IKeyEventHandler h)
   {
@@ -187,6 +188,8 @@ public final class Config
     current_layout_landscape = _prefs.getInt("current_layout_landscape", 0);
     circle_sensitivity = Integer.valueOf(_prefs.getString("circle_sensitivity", "2"));
     clipboard_history_enabled = _prefs.getBoolean("clipboard_history_enabled", false);
+    bottomInsetMin = Utils.is_navigation_bar_gestural(res) ?
+      (int)res.getDimension(R.dimen.bottom_inset_min) : 0;
   }
 
   public int get_current_layout()

srcs/juloo.keyboard2/Keyboard2.java

@@ -292,6 +292,15 @@ public class Keyboard2 extends InputMethodService
 
   private void updateSoftInputWindowLayoutParams() {
     final Window window = getWindow().getWindow();
+    // On API >= 30, Keyboard2View behaves as edge-to-edge
+    if (VERSION.SDK_INT >= 30)
+    {
+      WindowManager.LayoutParams wattrs = window.getAttributes();
+      wattrs.layoutInDisplayCutoutMode =
+        WindowManager.LayoutParams.LAYOUT_IN_DISPLAY_CUTOUT_MODE_ALWAYS;
+      // Allow to draw behind system bars
+      wattrs.setFitInsetsTypes(0);
+    }
     updateLayoutHeightOf(window, ViewGroup.LayoutParams.MATCH_PARENT);
     final View inputArea = window.findViewById(android.R.id.inputArea);
 

srcs/juloo.keyboard2/Keyboard2View.java

@@ -42,7 +42,9 @@ public class Keyboard2View extends View
   private Config _config;
 
   private float _keyWidth;
-  private float _bottomMargin;
+  private float _marginRight;
+  private float _marginLeft;
+  private float _marginBottom;
 
   private Theme _theme;
 
@@ -232,7 +234,7 @@ public class Keyboard2View extends View
   private KeyboardData.Key getKeyAtPosition(float tx, float ty)
   {
     KeyboardData.Row row = getRowAtPosition(ty);
-    float x = _config.horizontal_margin;
+    float x = _marginLeft;
     if (row == null || tx < x)
       return null;
     for (KeyboardData.Key key : row.keys)
@@ -256,28 +258,56 @@ public class Keyboard2View extends View
   @Override
   public void onMeasure(int wSpec, int hSpec)
   {
-    DisplayMetrics dm = getContext().getResources().getDisplayMetrics();
-    int width = dm.widthPixels;
-    _bottomMargin = _config.margin_bottom;
-    // Compatibility with display cutouts and navigation on the right
+    int width;
+    int insets_left = 0;
+    int insets_right = 0;
+    int insets_bottom = 0;
+    // LAYOUT_IN_DISPLAY_CUTOUT_MODE_ALWAYS is set in [Keyboard2#updateSoftInputWindowLayoutParams].
+    // and keyboard is allowed do draw behind status/navigation bars
     if (VERSION.SDK_INT >= 30)
     {
       WindowMetrics metrics =
         ((WindowManager)getContext().getSystemService(Context.WINDOW_SERVICE))
         .getCurrentWindowMetrics();
-      Insets insets = metrics.getWindowInsets().getInsetsIgnoringVisibility(
-          WindowInsets.Type.statusBars() | WindowInsets.Type.navigationBars()
-          | WindowInsets.Type.displayCutout());
-      width = metrics.getBounds().width() - insets.right - insets.left;
-      // Starting in API 35, keyboard window has LAYOUT_IN_DISPLAY_CUTOUT_MODE_ALWAYS
+      width = metrics.getBounds().width();
+      WindowInsets wi = metrics.getWindowInsets();
+      int insets_types =
+          WindowInsets.Type.statusBars()
+          | WindowInsets.Type.displayCutout()
+          | WindowInsets.Type.mandatorySystemGestures()
+          | WindowInsets.Type.navigationBars();
+      Insets insets = wi.getInsets(insets_types);
+      insets_left = insets.left;
+      insets_right = insets.right;
+      // On API 35, the keyboard is allowed to draw under the
+      // button-navigation bar but on lower APIs, it must be discounted from
+      // the width.
+      if (VERSION.SDK_INT < 35)
+      {
+        Insets nav_insets = wi.getInsets(WindowInsets.Type.navigationBars());
+        width -= nav_insets.left + nav_insets.right;
+        insets_left -= nav_insets.left;
+        insets_right -= nav_insets.right;
+      }
+      // [insets.bottom] doesn't take into account the buttons that appear in
+      // the gesture navigation bar when the IME is showing so ensure a minimum
+      // of margin is added.
       if (VERSION.SDK_INT >= 35)
-        _bottomMargin += insets.bottom;
+        insets_bottom = Math.max(insets.bottom, _config.bottomInsetMin);
+    }
+    else
+    {
+      DisplayMetrics dm = getContext().getResources().getDisplayMetrics();
+      width = dm.widthPixels;
     }
     int height =
       (int)(_config.keyHeight * _keyboard.keysHeight
-          + _config.marginTop + _bottomMargin);
+          + _config.marginTop + _marginBottom);
     setMeasuredDimension(width, height);
-    _keyWidth = (width - (_config.horizontal_margin * 2)) / _keyboard.keysWidth;
+    _marginLeft = Math.max(_config.horizontal_margin, insets_left);
+    _marginRight = Math.max(_config.horizontal_margin, insets_right);
+    _marginBottom = _config.margin_bottom + insets_bottom;
+    _keyWidth = (width - _marginLeft - _marginRight) / _keyboard.keysWidth;
   }
 
   @Override
@@ -289,10 +319,10 @@ public class Keyboard2View extends View
     {
       // Disable the back-gesture on the keyboard area
       Rect keyboard_area = new Rect(
-          left + (int)_config.horizontal_margin,
+          left + (int)_marginLeft,
           top + (int)_config.marginTop,
-          right - (int)_config.horizontal_margin,
-          bottom - (int)_bottomMargin);
+          right - (int)_marginRight,
+          bottom - (int)_marginBottom);
       setSystemGestureExclusionRects(Arrays.asList(keyboard_area));
     }
   }
@@ -327,7 +357,7 @@ public class Keyboard2View extends View
     for (KeyboardData.Row row : _keyboard.rows)
     {
       y += row.shift * _config.keyHeight;
-      float x = _config.horizontal_margin + key_horizontal_margin / 2;
+      float x = _marginLeft + key_horizontal_margin / 2;
       float keyH = row.height * _config.keyHeight - key_vertical_margin;
       for (KeyboardData.Key k : row.keys)
       {

srcs/juloo.keyboard2/Utils.java

@@ -1,8 +1,13 @@
 package juloo.keyboard2;
 
 import android.app.AlertDialog;
+import android.content.res.Resources;
+import android.graphics.Insets;
+import android.os.Build.VERSION;
 import android.os.IBinder;
+import android.view.View;
 import android.view.Window;
+import android.view.WindowInsets;
 import android.view.WindowManager;
 import java.io.InputStream;
 import java.io.InputStreamReader;
@@ -44,4 +49,14 @@ public final class Utils
       out.append(buff, 0, l);
     return out.toString();
   }
+
+  /** Whether the thin gesture-navigation bar is used.
+      https://stackoverflow.com/questions/36514167/how-to-really-get-the-navigation-bar-height-in-android
+       */
+  public static boolean is_navigation_bar_gestural(Resources res)
+  {
+    // core/java/android/view/WindowManagerPolicyConstants.java
+    int res_id = res.getIdentifier("config_navBarInteractionMode", "integer", "android");
+    return (res_id > 0 && res.getInteger(res_id) == 2);
+  }
 }