flutter_bloc许多BlocBuilder的事件

问题描述

最近我正在学习Flutter_bloc，并引用了项目flutter_weather。

让我感到困惑的是，如果一个Bloc类有很多事件，并且大多数Event都将有State返回的值，并且有很多{{1} }中的项目，如果我想让BlocBuilder只响应某个BlocBuilder怎么办？

我能想到的方法是将这个Event分为多个Bloc，或者将每个值都视为Bloc的属性，Bloc使用BlocBuilder方法来确定是否重建。

但这两种方法都不适合我。有什么好的方法吗？最好在github上有项目以供参考。

例如：这是事件：

buildwhen

这是状态：

abstract class WeatherEvent extends Equatable {
  const WeatherEvent();
}

class WeatherRequested extends WeatherEvent {
  final String city;

  const WeatherRequested({@required this.city}) : assert(city != null);

  @override
  List<Object> get props => [city];
}

class WeatherRefreshRequested extends WeatherEvent {
  final String city;

  const WeatherRefreshRequested({@required this.city}) : assert(city != null);

  @override
  List<Object> get props => [city];
}

这是集团：

abstract class WeatherState extends Equatable {
  const WeatherState();

  @override
  List<Object> get props => [];
}

class WeatherInitial extends WeatherState {}

class WeatherLoadInProgress extends WeatherState {}

class WeatherLoadSuccess extends WeatherState {
  final Weather weather;

  const WeatherLoadSuccess({@required this.weather}) : assert(weather != null);

  @override
  List<Object> get props => [weather];
}

class WeatherLoadFailure extends WeatherState {}

这是BlocConsumer：

class WeatherBloc extends Bloc<WeatherEvent,WeatherState> {
  final WeatherRepository weatherRepository;

  WeatherBloc({@required this.weatherRepository})
      : assert(weatherRepository != null),super(WeatherInitial());

  @override
  Stream<WeatherState> mapEventToState(WeatherEvent event) async* {
    if (event is WeatherRequested) {
      yield* _mapWeatherRequestedToState(event);
    } else if (event is WeatherRefreshRequested) {
      yield* _mapWeatherRefreshRequestedToState(event);
    }
  }

  Stream<WeatherState> _mapWeatherRequestedToState(
    WeatherRequested event,) async* {
    yield WeatherLoadInProgress();
    try {
      final Weather weather = await weatherRepository.getWeather(event.city);
      yield WeatherLoadSuccess(weather: weather);
    } catch (_) {
      yield WeatherLoadFailure();
    }
  }

  Stream<WeatherState> _mapWeatherRefreshRequestedToState(
    WeatherRefreshRequested event,) async* {
    try {
      final Weather weather = await weatherRepository.getWeather(event.city);
      yield WeatherLoadSuccess(weather: weather);
    } catch (_) {}
  }
}

问题是我希望BlocBuilder1仅在事件类型为WeatherRequested时才能工作，而BlocBuilder2仅在事件类型为WeatherRefreshRequested时才能工作。我的想法之一是，每个事件都有自己的状态，然后在构建时判断状态的类型。

有什么好的方法吗？

解决方法

如果要构建窗口小部件以响应某些状态，则应使用 BlocConsumer ，并在 buildWhen 中告诉该bloc告诉它应该在什么状态下构建/重建小部件。

BlocConsumer<QuizBloc,QuizState>(
  buildWhen: (previous,current) {
    if (current is QuizPoints)
      return true;
    else
      return false;
  },listener: (context,state) {},builder: (context,state) {
    if (state is QuizPoints)
      return Container(
        child: Center(
          child: Countup(
            begin: 0,end: state.points,duration: Duration(seconds: 2),separator: ',',),);
    else
      return Container();
  },);

bloc flutter-bloc