values.dart

class CounterListenableProvider extends InheritedWidget {
  final ValueListenable<int> counter;

  CounterListenableProvider({Key key, @required this.counter, Widget child})
      : super(key: key, child: child);

  @override
  bool updateShouldNotify(InheritedWidget oldWidget) {
    return true;
  }

  static ValueListenable<int> of(BuildContext context) {
    return (context.inheritFromWidgetOfExactType(CounterListenableProvider)
            as CounterListenableProvider)
        .counter;
  }
}