颤振块迁移

Question

我在迁移到新版本的 flutter_bloc 时遇到问题。 这个：

Stream<NewsState> mapEventToState(NewsEvent event) async* {
    if (event is FetchTopAndOtherNewsEvent) yield* _repository.fetchTopAndOtherNews(event);
    if (event is FetchNewsEvent) yield* _repository.fetchNews(event);
  }

我重写为：

class NewsBloc extends Bloc<NewsEvent, NewsState> {
  final NewsRepository _repository = NewsRepository();
  NewsBloc() : super(NewsInitialState()){
    on((event, emit) {
      if (event is FetchTopAndOtherNewsEvent) emit(_repository.fetchTopAndOtherNews(event));
      if (event is FetchNewsEvent) emit(_repository.fetchNews(event));
    });
  }

但可以理解的是，它给出了一个错误，参数类型“Stream”不能分配给参数类型“NewsState”。

Answer 1

我目前使用喜欢

class NewsBloc extends Bloc<NewsEvent, NewsState> {
  NewsBloc() : super(NewsInitial()) {
    on<FetchTopAndOtherNewsEvent>(_fetchTopAndOtherNewsEvent);
    on<FetchNewsEvent>(_onFetchNewsEvent);
  }

  _fetchTopAndOtherNewsEvent(FetchTopAndOtherNewsEvent event, emit) { /// event job
}

  _onFetchNewsEvent(FetchNewsEvent event, emit) {/// event job
 }
}

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