enabled background blending on Android 15 for improved edge-to-edge experience

app/src/main/java/io/github/sspanak/tt9/ime/UiHandler.java

@@ -10,6 +10,7 @@ import io.github.sspanak.tt9.ime.modes.InputModeKind;
 import io.github.sspanak.tt9.preferences.settings.SettingsStore;
 import io.github.sspanak.tt9.ui.main.ResizableMainView;
 import io.github.sspanak.tt9.ui.tray.StatusBar;
+import io.github.sspanak.tt9.util.SystemSettings;
 
 abstract class UiHandler extends AbstractHandler {
 	protected SettingsStore settings;
@@ -44,6 +45,7 @@ abstract class UiHandler extends AbstractHandler {
 		statusBar.setText(inputMode);
 		mainView.hideCommandPalette();
 		mainView.render();
+		SystemSettings.setNavigationBarDarkTheme(getWindow().getWindow(), settings.getDarkTheme());
 
 		if (!isInputViewShown()) {
 			updateInputViewShown();

app/src/main/java/io/github/sspanak/tt9/ui/main/BaseMainLayout.java

@@ -1,5 +1,6 @@
 package io.github.sspanak.tt9.ui.main;
 
+import android.graphics.Color;
 import android.graphics.Insets;
 import android.os.Build;
 import android.view.ContextThemeWrapper;
@@ -238,6 +239,45 @@ abstract class BaseMainLayout {
 	}
 
 
+	private boolean shouldEnableBackgroundBlending() {
+		if (view == null || tt9 == null) {
+			return true;
+		}
+
+		boolean isLandscape = DeviceInfo.isLandscapeOrientation(view.getContext());
+		int width = tt9.getSettings().getWidthPercent();
+
+		return
+			Build.VERSION.SDK_INT >= Build.VERSION_CODES.VANILLA_ICE_CREAM
+			&& ((isLandscape && width >= 75) || (!isLandscape && width >= 65));
+	}
+
+
+	protected void setBackgroundBlending() {
+		if (view == null) {
+			return;
+		}
+
+		boolean yes = shouldEnableBackgroundBlending();
+
+		view.setBackgroundColor(
+				yes ? view.getContext().getResources().getColor(R.color.keyboard_background) : Color.TRANSPARENT
+		);
+
+		final int separatorVisibility = yes ? View.VISIBLE : View.GONE;
+
+		View leftBumperTopSeparator = view.findViewById(R.id.bumper_left_top_separator);
+		if (leftBumperTopSeparator != null) {
+			leftBumperTopSeparator.setVisibility(separatorVisibility);
+		}
+
+		View rightBumperTopSeparator = view.findViewById(R.id.bumper_right_top_separator);
+		if (rightBumperTopSeparator != null) {
+			rightBumperTopSeparator.setVisibility(separatorVisibility);
+		}
+	}
+
+
 	abstract void showCommandPalette();
 	abstract void hideCommandPalette();
 	abstract boolean isCommandPaletteShown();

app/src/main/java/io/github/sspanak/tt9/ui/main/MainLayoutNumpad.java

@@ -276,6 +276,7 @@ class MainLayoutNumpad extends BaseMainLayout {
 		preventEdgeToEdge();
 		setWidth(tt9.getSettings().getWidthPercent(), tt9.getSettings().getAlignment());
 		setKeyColumnWidth(tt9.getSettings().getNumpadFnKeyScale());
+		setBackgroundBlending();
 		showLongSpace(
 			tt9.getSettings().isNumpadShapeLongSpace() && !tt9.isInputModeNumeric() && !LanguageKind.isKorean(tt9.getLanguage()),
 			defaultKeyHeight

app/src/main/java/io/github/sspanak/tt9/ui/main/MainLayoutTray.java

@@ -88,6 +88,7 @@ class MainLayoutTray extends BaseMainLayout {
 		setSoftKeysVisibility();
 		preventEdgeToEdge();
 		setWidth(tt9.getSettings().getWidthPercent(), tt9.getSettings().getAlignment());
+		setBackgroundBlending();
 		enableClickHandlers();
 		for (SoftKey key : getKeys()) {
 			key.render();

app/src/main/java/io/github/sspanak/tt9/util/SystemSettings.java

@@ -4,6 +4,8 @@ import android.content.Context;
 import android.os.Build;
 import android.os.LocaleList;
 import android.provider.Settings;
+import android.view.Window;
+import android.view.WindowInsetsController;
 import android.view.inputmethod.InputMethodInfo;
 import android.view.inputmethod.InputMethodManager;
 
@@ -68,4 +70,25 @@ public class SystemSettings {
 
 		return null;
 	}
+
+	/**
+	 * Even though the background changes automatically on Android 15, thanks to edge-to-edge,
+	 * the text/icon color remains the device default. This function allows us to change it.
+	 * @see : <a href="https://stackoverflow.com/a/77240330">the only working solution</a>.
+	 */
+	public static void setNavigationBarDarkTheme(@Nullable Window window, boolean dark) {
+		if (Build.VERSION.SDK_INT < Build.VERSION_CODES.R) {
+			return;
+		}
+
+		WindowInsetsController insetsController = window != null ? window.getInsetsController() : null;
+		if (insetsController == null) {
+			return;
+		}
+
+		insetsController.setSystemBarsAppearance(
+			dark ? 0 : WindowInsetsController.APPEARANCE_LIGHT_NAVIGATION_BARS,
+			WindowInsetsController.APPEARANCE_LIGHT_NAVIGATION_BARS
+		);
+	}
 }

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

@@ -3,7 +3,9 @@
 	xmlns:android="http://schemas.android.com/apk/res/android"
 	style="@style/TTheme.FullScreenContainer">
 
-	<LinearLayout style="@style/TTheme.FullScreenContainer.SideBumper" android:id="@+id/bumper_left" />
+	<LinearLayout style="@style/TTheme.FullScreenContainer.SideBumper" android:id="@+id/bumper_left">
+		<View android:id="@+id/bumper_left_top_separator" style="@style/TTheme.Bumper.TopSeparator" />
+	</LinearLayout>
 
 	<LinearLayout style="@style/TTheme.Numpad" android:id="@+id/keyboard_container">
 		<View style="@style/TTheme.Keyboard.TopSeparator" />
@@ -27,6 +29,8 @@
 		</LinearLayout>
 	</LinearLayout>
 
-	<LinearLayout style="@style/TTheme.FullScreenContainer.SideBumper" android:id="@+id/bumper_right" />
+	<LinearLayout style="@style/TTheme.FullScreenContainer.SideBumper" android:id="@+id/bumper_right">
+		<View android:id="@+id/bumper_right_top_separator" style="@style/TTheme.Bumper.TopSeparator" />
+	</LinearLayout>
 
 </LinearLayout>

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

@@ -3,7 +3,9 @@
 	xmlns:android="http://schemas.android.com/apk/res/android"
 	style="@style/TTheme.FullScreenContainer">
 
-	<LinearLayout style="@style/TTheme.FullScreenContainer.SideBumper" android:id="@+id/bumper_left" />
+	<LinearLayout style="@style/TTheme.FullScreenContainer.SideBumper" android:id="@+id/bumper_left">
+		<View android:id="@+id/bumper_left_top_separator" style="@style/TTheme.Bumper.TopSeparator" />
+	</LinearLayout>
 
 	<LinearLayout style="@style/TTheme.MainSmall" android:id="@+id/keyboard_container">
 		<View style="@style/TTheme.Keyboard.TopSeparator" />
@@ -21,6 +23,8 @@
 			android:visibility="gone" />
 	</LinearLayout>
 
-	<LinearLayout style="@style/TTheme.FullScreenContainer.SideBumper" android:id="@+id/bumper_right" />
+	<LinearLayout style="@style/TTheme.FullScreenContainer.SideBumper" android:id="@+id/bumper_right">
+		<View android:id="@+id/bumper_right_top_separator" style="@style/TTheme.Bumper.TopSeparator" />
+	</LinearLayout>
 
 </LinearLayout>

app/src/main/res/values-land/dimens.xml

@@ -1,4 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
+	<!-- only used for calculating the initial default width -->
 	<dimen name="numpad_max_width">720dp</dimen>
 </resources>

app/src/main/res/values-v35/colors.xml

@@ -1,5 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
+	<color name="keyboard_wrapper_background">@color/keyboard_background</color>
+	<color name="keyboard_wrapper_top_separator">@color/keyboard_top_separator</color>
+
 	<color name="key_lf4_background">@color/key_fn_background</color>
 	<color name="key_lf4_ripple">@color/key_fn_ripple</color>
 	<color name="key_lf4_text">@color/key_fn_text</color>

app/src/main/res/values/colors.xml

@@ -10,6 +10,8 @@
 	<color name="keyboard_background">#e8eaed</color>
 	<color name="keyboard_text">#3d3d3f</color>
 	<color name="keyboard_top_separator">@color/key_fn_background</color>
+	<color name="keyboard_wrapper_background">#00000000</color>
+	<color name="keyboard_wrapper_top_separator">#00000000</color>
 
 	<color name="key_num_background">#fff</color>
 	<color name="key_num_ripple">#eff0f1</color>

app/src/main/res/values/styles.xml

@@ -11,6 +11,7 @@
 		<item name="android:layout_height">wrap_content</item>
 		<item name="android:layoutDirection">ltr</item>
 		<item name="android:orientation">horizontal</item>
+		<item name="android:background">@color/keyboard_wrapper_background</item>
 	</style>
 
 	<style name="TTheme.FullScreenContainer.SideBumper" parent="">
@@ -40,6 +41,10 @@
 		<item name="android:background">@color/keyboard_top_separator</item>
 	</style>
 
+	<style name="TTheme.Bumper.TopSeparator" parent="TTheme.Keyboard.TopSeparator">
+		<item name="android:background">@color/keyboard_wrapper_top_separator</item>
+	</style>
+
 	<!--*******************************************
 		Small
 	*******************************************-->