使用状态更改观察器，我可以看到我的集团将其状态更改LoadInProgress为PmLoadSuccess. 但是，更改为 时不会调用小部件LoadInProgress。我在 中有一个断点，但是，代码仅在发出BlocBuilder时才会停在那里。PmLoadSuccess
我的状态定义
@freezed
class ProblemManagerState with _$ProblemManagerState {
const factory ProblemManagerState.initial() = PmInitial;
const factory ProblemManagerState.loadInProgress() = PmLoadInProgress;
const factory ProblemManagerState.loadSuccess(
Problem problem) = PmLoadSuccess;
) = PmSyncFailed;
}
集团
@injectable
class ProblemManagerBloc extends Bloc<ProblemManagerEvent, ProblemManagerState> {
final IProblemsRepository problemsRepository;
ProblemManagerBloc(this.problemsRepository) : super(PmInitial());
@override
Stream<ProblemManagerState> mapEventToState(
ProblemManagerEvent event,
) async* {
yield PmLoadInProgress(); // <<< does not emit to widget
yield* event.map(
pmProblemRequested: (e) async* {
yield ProblemManagerState.loadInProgress(); // <<< doesn't emit either
print (state);
yield* _mapPmProblemRequestedToState(e);
},
);
}
Stream<ProblemManagerState> _mapPmProblemRequestedToState(/*PmProblemRequested*/dynamic event) async* {
dynamic nextProblem;
late int problemClassId;
problemClassId = event.problemClassId!;
}
final String rootId = await _getNextProblemRootId(problemClassId);
final Either<StorageFailure, Problem> failureOrProblem = await problemsRepository.getProblem(rootId);
yield failureOrProblem.fold(
(fail) => PmLoadFailure(fail),
(load) => PmLoadSuccess(load)); // <<< yield does emit to widget
}
小部件（如果加载成功则调用另一个小部件）
class ProblemManagerPage extends StatelessWidget {
@override
Widget build(BuildContext context) {
return BlocBuilder<ProblemManagerBloc, ProblemManagerState>(
builder: (context, state) {
return state.map( // <<< breakpoint not reached with PmLoadInProgress (=ProblemManagerState.loadInProgress)
initial: (_) => Container(),
loadInProgress: (_) => const Center(
child: CircularProgressIndicator(),
),
loadSuccess: (state) => PmGateway(state.problem),
);
}
);
}
}