Flutter - Theme Toggle from Drawer

main.dart

import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';

const Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() {
  runApp(App());
}

class App extends StatelessWidget {
  /// {@macro app}
  const App({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return BlocProvider(
      create: (_) => ThemeCubit(),
      child: MyApp(),
    );
  }
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return BlocBuilder<ThemeCubit, ThemeData>(
      builder: (_, theme) {
        return MaterialApp(
          theme: theme,
          home: MyPage(),
        );
      },
    );
  }
}

class MyPage extends StatefulWidget {
  const MyPage({super.key});

  @override
  State<MyPage> createState() => _MyPageState();
}

class _MyPageState extends State<MyPage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text("Home")),
      body: Container(color: const Color(0xFFFFE306)),
      drawer: Drawer(
        child: ListView(
          // Important: Remove any padding from the ListView.
          padding: EdgeInsets.zero,
          children: <Widget>[
            const DrawerHeader(
              decoration: BoxDecoration(color: Color(0x4D4971FF)),
              //https://gist.github.com/lopspower/03fb1cc0ac9f32ef38f4
              child: Text(
                'Header',
              ),
            ),
            ListTile(
              leading: const Icon(Icons.brush),
              title: const Text(
                'Dark Mode',
              ),
              trailing: Switch(
                value: context.read<ThemeCubit>().state.brightness ==
                    Brightness.dark,
                onChanged: (value) {
                  context.read<ThemeCubit>().toggleBrightness();
                },
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class ThemeCubit extends Cubit<ThemeData> {
  /// {@macro brightness_cubit}
  ThemeCubit() : super(_lightTheme);

  static final _lightTheme = ThemeData(
    floatingActionButtonTheme: const FloatingActionButtonThemeData(
      foregroundColor: Colors.white,
    ),
    brightness: Brightness.light,
  );

  static final _darkTheme = ThemeData(
    floatingActionButtonTheme: const FloatingActionButtonThemeData(
      foregroundColor: Colors.black,
    ),
    brightness: Brightness.dark,
  );

  /// Toggles the current brightness between light and dark.
  void toggleBrightness() {
    emit(state.brightness == Brightness.dark ? _lightTheme : _darkTheme);
  }
}