子块调用其祖先 mapEventToState答案

【问题标题】：Child bloc calling its ancestor mapEventToState子块调用其祖先 mapEventToState
【发布时间】：2021-10-07 07:01:51
【问题描述】：

我正在尝试创建一个处理常见事件的CustomBloc。 CustomBloc 被许多其他集团扩展以添加功能。我的问题是super.mapEventToState 在CustomBloc 后代中的调用永远不会被执行。

class CustomBloc extends Bloc<BlocEvent, BlocState> {
  CustomBloc(BlocState initialState) : super(initialState) 
  @override
  Stream<BlocState> mapEventToState(BlocEvent event) async* {
    if (event is BlocInitialEvent) {
      yield BlocInitialState(BlocStatus.blocBusy)
      try {
         //do something
        yield BlocInitialState(BlocStatus.blocReady);
      } catch (e) {
        yield BlocInitialState(BlocStatus.blocError);
      }
    }
  }
}

现在让我们子类化我们的自定义块：

class HomeBloc extends CustomBloc {
  HomeBloc(BlocState initialState) : super(initialState);
 
  @override
  Stream<BlocState> mapEventToState(BlocEvent event) async* {
    super.mapEventToState(event);// the event is never dispatched to CustomBloc
  //Handle more events
  }
}

HomeBloc(BlocInitialState(BlocStatus.blocReady)).Add(BlocInitialEvent);// BlocInitialEvent never gets dispatched to the ancestor class

请注意，如果我不在HomeBloc 中覆盖mapEventToState，一切正常。有什么想法吗？

【问题讨论】：

标签： flutter-bloc

【解决方案1】：

您需要从super.mapEventToState(event); 产生状态

所以尝试拨打yield* super.mapEventToState(event);

【讨论】：