/***** main.dart *****/
class DiceNotifier extends ChangeNotifier {
  List<DieWidget> dice = [];

  void add() {
    dice.add(DieWidget());
    notifyListeners();
  }

  void removeDie(int id) {
    print(id);
    notifyListeners();
  }
}

final diceProvider = ChangeNotifierProvider((_) {
  return DiceNotifier();
});

class MyHomePage extends ConsumerWidget {
  @override
  Widget build(BuildContext context, ScopedReader watch) {
    final dice = watch(diceProvider).dice;
    return Scaffold(
      appBar: AppBar(
        title: Text("Dice"),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            ...dice,
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          context.read(diceProvider).add();
        },
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

/***** die_widget.dart *****/
class DieWidget extends StatefulWidget {
  @override
  _DieWidgetState createState() => _DieWidgetState();
}

class _DieWidgetState extends State<DieWidget> {
  int value = 0;
  int id = 0;
  @override
  Widget build(BuildContext context) {
    return FlatButton(
      child: Text(
        '$value',
      ),
      onPressed: () {
        setState(() {
          value++;
          id++;
        });
        // context.read(dieProvider).increment();
      },
      onLongPress: () {
        final dice = context.read(diceProvider);
        dice.removeDie(id);
        // print(this.value);
      },
    );
  }
}