StepperBloc.dart

class StepperBloc extends Bloc<StepperEvent, StepperState> {
  void onContinue() {
    dispatch(ContinueEvent());
  }

  void onBack() {
    dispatch(BackEvent());
  }

  void onSaveRate(double rate, double volume) {
    dispatch(SaveRateEvent(rate: rate, volume: volume));
  }

  @override
  StepperState get initialState => StepperState.initial();

  @override
  Stream<StepperState> mapEventToState(StepperState state, StepperEvent event) async* {
    final _currentState = currentState;
    if (event is ContinueEvent) {
      yield StepperState(currentStep: _currentState.currentStep + 1, rate: _currentState.rate, volume: _currentState.volume);
    } else if (event is BackEvent) {
      yield StepperState(currentStep: _currentState.currentStep - 1, rate: _currentState.rate, volume: _currentState.volume);
    } else if (event is SaveRateEvent) {
      yield StepperState(currentStep: _currentState.currentStep, rate: event.rate, volume: event.volume);
    }
  }
}