Easy Theme Manager

easy_theme_manager.dart

class EasyTheme extends InheritedWidget {
  final ValueNotifier<ThemeMode> theme = ValueNotifier(ThemeMode.system);

  EasyTheme({required super.child, super.key});

  static EasyTheme? maybeOf(BuildContext context) =>
      context.dependOnInheritedWidgetOfExactType<EasyTheme>();

  static EasyTheme of(BuildContext context) {
    final EasyTheme? result = maybeOf(context);
    assert(result != null, 'No EasyThemeManager found in context');
    return result!;
  }

  void toggleTheme() {
    final isLightTheme = theme.value == ThemeMode.light;
    theme.value = isLightTheme ? ThemeMode.dark : ThemeMode.light;
  }

  @override
  bool updateShouldNotify(covariant EasyTheme oldWidget) =>
      oldWidget.theme.value != theme.value;
}

class EasyThemeBuilder extends StatelessWidget {
  final Widget Function(BuildContext context, ThemeMode themeMode) builder;

  const EasyThemeBuilder({
    required this.builder,
    super.key,
  });

  @override
  Widget build(BuildContext context) {
    return EasyTheme(
      child: Builder(builder: (context) {
        return ValueListenableBuilder(
          valueListenable: EasyTheme.of(context).theme,
          builder: (context, value, _) {
            return builder.call(context, value);
          },
        );
      }),
    );
  }
}