Fix margin calculation on Android 14

The back and IME switching buttons that appear in the navigation bar are
not accounted by WindowInsets and would overlap with the keyboard.

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;
-    int width = dm.widthPixels;
+    int insets_left = 0;
-    _bottomMargin = _config.margin_bottom;
+    int insets_right = 0;
-    // Compatibility with display cutouts and navigation on the right
+    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(
+      width = metrics.getBounds().width();
-          WindowInsets.Type.statusBars() | WindowInsets.Type.navigationBars()
+      WindowInsets wi = metrics.getWindowInsets();
-          | WindowInsets.Type.displayCutout());
+      int insets_types =
-      width = metrics.getBounds().width() - insets.right - insets.left;
+          WindowInsets.Type.statusBars()
-      // Starting in API 35, keyboard window has LAYOUT_IN_DISPLAY_CUTOUT_MODE_ALWAYS
+          | 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,
+          right - (int)_marginRight,
-          bottom - (int)_bottomMargin);
+          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);
+  }
 }