BLoC 的事件映射器未执行，但调试建议它应该 8-/

Question

这很奇怪，也许你们中有人知道会发生什么：

我的集团有一些事件，以下事件导致了问题（其他尚未实施）：

@freezed
abstract class ProblemManagerEvent with _$ProblemManagerEvent {
  const factory ProblemManagerEvent.pmDataSyncRequested() = PmDataSyncRequested;
}

这应该会导致 bloc 发出一个状态

@injectable
class ProblemManagerBloc extends Bloc<ProblemManagerEvent, ProblemManagerState> {
  final IJournalsRepository journalsRepository;
  final IProblemsRepository problemsRepository;

  ProblemManagerBloc(this.journalsRepository, this.problemsRepository) : super(PmInitial());
  @override
  Stream<ProblemManagerState> mapEventToState(
    ProblemManagerEvent event,
  ) async* {
    print('before map $event');    // <<<<<<<<<<<<<<<<<<<<<<<<
    event.map(
      pmDataSyncRequested: (e) async* {
        print('in map $e');    // <<<<<<<<<<<<<<<<<<<<<<<<<<<<
        final Either<StorageFailure, Unit> response = await problemsRepository.syncProblems();
        response.fold (
          (f) async* {yield PmSyncFailed(f);},
          (s) async* {yield PmInitial();});
        print('yep');
        yield ProblemManagerState.initial();
      },
      pmClassProblemRequested: (e) async* {
        yield ProblemManagerState.initial(); //todo
      },
      pmRandomProblemRequested: (e) async* {
        yield ProblemManagerState.initial();  //todo
      }
    );
    print('post map');    // <<<<<<<<<<<<<<<<
  }
}

这会产生以下输出

Restarted application in 4.549ms.
flutter: before map ProblemManagerEvent.pmDataSyncRequested()
flutter: post map
flutter: before map ProblemManagerEvent.pmDataSyncRequested()
flutter: post map

因此，即使它打印了正确的事件，mapEventToState 也不会触发与该事件关联的代码。尽管如此，它还是完成了 bloc 的代码，并出于某种原因再次运行该事件（一些出于某种原因进行了重建）。事件是这样触发的，下面的widgets都渲染在了屏幕上。

class ProblemPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final StackRouter router = context.router;
    return PlatformScaffold(
      appBar: PlatformAppBar(title: const Text('Home')),
      body: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
            BlocBuilder<ProblemManagerBloc, ProblemManagerState>(
            builder: (context, state) {
              context.read<ProblemManagerBloc>().add(PmDataSyncRequested());
              return Column (children:[
              Text('Hello world!'),
              TextButton(child:Text('los'),
                onPressed: () {print('home');

Answer 1

在 event.map(...) 之前缺少

yield*。现在，它基本上与 void 函数没有 return/yield 任何东西相同。

BLoC 的事件映射器未执行，但调试建议它应该 8-/

event mapper of BLoC not executed, though debugging suggests it should 8-/

flutter

events

stream

mapping

bloc