[RNMobile] - Implements Dark Mode on Android platform (#19293)

packages/compose/src/hooks/use-preferred-color-scheme/index.android.js

@@ -0,0 +1,33 @@
+/**
+ * External dependencies
+ */
+import {
+	subscribePreferredColorScheme,
+	isInitialColorSchemeDark,
+} from 'react-native-gutenberg-bridge';
+/**
+ * WordPress dependencies
+ */
+import { useState, useEffect } from '@wordpress/element';
+
+/**
+ * Returns the color scheme value when it changes. Possible values: [ 'light', 'dark' ]
+ *
+ * @return {string} return current color scheme.
+ */
+const usePreferredColorScheme = function() {
+	const [ currentColorScheme, setCurrentColorScheme ] = useState(
+		isInitialColorSchemeDark ? 'dark' : 'light'
+	);
+	useEffect( () => {
+		subscribePreferredColorScheme( ( { isPreferredColorSchemeDark } ) => {
+			const colorScheme = isPreferredColorSchemeDark ? 'dark' : 'light';
+			if ( colorScheme !== currentColorScheme ) {
+				setCurrentColorScheme( colorScheme );
+			}
+		} );
+	} );
+	return currentColorScheme;
+};
+
+export default usePreferredColorScheme;

test/native/setup.js

@@ -13,6 +13,7 @@ jest.mock( 'react-native-gutenberg-bridge', () => {
 		subscribeSetFocusOnTitle: jest.fn(),
 		subscribeUpdateHtml: jest.fn(),
 		subscribeMediaAppend: jest.fn(),
+		subscribePreferredColorScheme: () => 'light',
 		editorDidMount: jest.fn(),
 		editorDidAutosave: jest.fn(),
 		subscribeMediaUpload: jest.fn(),