调用其祖先 mapEventToState 的子块

Question

我正在尝试创建一个 CustomBloc 来处理常见事件。 CustomBloc 由许多其他 Bloc 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);
      }
    }
  }
}

现在让我们对自定义集团进行子类化：

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，如果我不覆盖 HomeBloc 中的 mapEventToState，一切正常。有什么想法吗？

Answer 1

您需要从 super.mapEventToState(event);

产生状态

所以尝试调用 yield* super.mapEventToState(event);

调用其祖先 mapEventToState 的子块

Child bloc calling its ancestor mapEventToState

flutter-bloc