Android: Add method to set root window color at runtime

platform/android/display_server_android.cpp

@@ -626,6 +626,12 @@ bool DisplayServerAndroid::can_any_window_draw() const {
 	return true;
 }
 
+void DisplayServerAndroid::window_set_color(const Color &p_color) {
+	GodotJavaWrapper *godot_java = OS_Android::get_singleton()->get_godot_java();
+	ERR_FAIL_NULL(godot_java);
+	godot_java->set_window_color(p_color);
+}
+
 void DisplayServerAndroid::process_events() {
 	Input::get_singleton()->flush_buffered_events();
 }

platform/android/display_server_android.h

@@ -220,6 +220,8 @@ public:
 	virtual void window_set_vsync_mode(DisplayServer::VSyncMode p_vsync_mode, WindowID p_window = MAIN_WINDOW_ID) override;
 	virtual DisplayServer::VSyncMode window_get_vsync_mode(WindowID p_vsync_mode) const override;
 
+	virtual void window_set_color(const Color &p_color) override;
+
 	virtual void process_events() override;
 
 	void process_accelerometer(const Vector3 &p_accelerometer);

platform/android/java/lib/src/org/godotengine/godot/Godot.kt

@@ -260,16 +260,7 @@ class Godot private constructor(val context: Context) {
 					useImmersive.set(true)
 					newArgs.add(commandLine[i])
 				} else if (commandLine[i] == "--background_color") {
-					val colorStr = commandLine[i + 1]
-					try {
-						backgroundColor = colorStr.toColorInt()
-						Log.d(TAG, "background color = $backgroundColor")
-					} catch (e: java.lang.IllegalArgumentException) {
-						Log.d(TAG, "Failed to parse background color: $colorStr")
-					}
-					runOnHostThread {
-						getActivity()?.window?.decorView?.setBackgroundColor(backgroundColor)
-					}
+					setWindowColor(commandLine[i + 1])
 				} else if (commandLine[i] == "--use_apk_expansion") {
 					useApkExpansion = true
 				} else if (hasExtra && commandLine[i] == "--apk_expansion_md5") {
@@ -492,6 +483,21 @@ class Godot private constructor(val context: Context) {
 		}
 	}
 
+	fun setWindowColor(colorStr: String) {
+		val color = try {
+			colorStr.toColorInt()
+		} catch (e: java.lang.IllegalArgumentException) {
+			Log.w(TAG, "Failed to parse background color: $colorStr", e)
+			return
+		}
+		val decorView = getActivity()?.window?.decorView ?: return
+		runOnHostThread {
+			decorView.setBackgroundColor(color)
+			backgroundColor = color
+			setSystemBarsAppearance()
+		}
+	}
+
 	/**
 	 * Used to complete initialization of the view used by the engine for rendering.
 	 *

platform/android/java_godot_wrapper.cpp

@@ -85,6 +85,7 @@ GodotJavaWrapper::GodotJavaWrapper(JNIEnv *p_env, jobject p_godot_instance) {
 	_verify_apk = p_env->GetMethodID(godot_class, "nativeVerifyApk", "(Ljava/lang/String;)I");
 	_enable_immersive_mode = p_env->GetMethodID(godot_class, "nativeEnableImmersiveMode", "(Z)V");
 	_is_in_immersive_mode = p_env->GetMethodID(godot_class, "isInImmersiveMode", "()Z");
+	_set_window_color = p_env->GetMethodID(godot_class, "setWindowColor", "(Ljava/lang/String;)V");
 	_on_editor_workspace_selected = p_env->GetMethodID(godot_class, "nativeOnEditorWorkspaceSelected", "(Ljava/lang/String;)V");
 	_get_activity = p_env->GetMethodID(godot_class, "getActivity", "()Landroid/app/Activity;");
 }
@@ -587,6 +588,16 @@ bool GodotJavaWrapper::is_in_immersive_mode() {
 	}
 }
 
+void GodotJavaWrapper::set_window_color(const Color &p_color) {
+	if (_set_window_color) {
+		JNIEnv *env = get_jni_env();
+		ERR_FAIL_NULL(env);
+		String color = "#" + p_color.to_html(false);
+		jstring jStrColor = env->NewStringUTF(color.utf8().get_data());
+		env->CallVoidMethod(godot_instance, _set_window_color, jStrColor);
+	}
+}
+
 void GodotJavaWrapper::on_editor_workspace_selected(const String &p_workspace) {
 	if (_on_editor_workspace_selected) {
 		JNIEnv *env = get_jni_env();

platform/android/java_godot_wrapper.h

@@ -81,6 +81,7 @@ private:
 	jmethodID _verify_apk = nullptr;
 	jmethodID _enable_immersive_mode = nullptr;
 	jmethodID _is_in_immersive_mode = nullptr;
+	jmethodID _set_window_color = nullptr;
 	jmethodID _on_editor_workspace_selected = nullptr;
 	jmethodID _get_activity = nullptr;
 
@@ -137,5 +138,7 @@ public:
 	void enable_immersive_mode(bool p_enabled);
 	bool is_in_immersive_mode();
 
+	void set_window_color(const Color &p_color);
+
 	void on_editor_workspace_selected(const String &p_workspace);
 };