future_counter_with_error_changenotifier.dart

class FutureCounterWithError extends ChangeNotifier {
  int _count = 0;
  int get count => _count;

  bool isLoaded = false;
  bool hasError = false;
  String errorMessage;

  Future<void> increment() async {
    isLoaded = false;
    notifyListeners();

    await Future<void>.delayed(const Duration(seconds: 1));

    try {
      if (Random().nextBool()) {
        throw CounterError('There is a problem in your counter');
      }

      isLoaded = true;
      hasError = false;
      _count++;
      notifyListeners();

    } catch (e) {
      hasError = true;
      errorMessage = 'There is a problem in your counter';
      notifyListeners();
    }
  }
}