将块作为参数传递给小部件

Question

如何将块对象作为参数传递给小部件，如下所示：

我希望能够将一个块 (TimerBloc) 或另一个块 (AnotherBloc) 传递到此类，并使用它返回带有该块的 BlocBuilder。

像这样：TimerField(bloc:TimerBloc) 或者这样： TimerField(bloc:AnotherBloc)

class TimerField extends StatelessWidget {
  final [Not sure of the class] bloc;

  const TimerField({
    Key key,
    @required this.bloc,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return BlocBuilder<[THE BLOC THAT WAS PASSED IN], [AND THE STATE]>(
      .......

Answer 1

abstract class BaseBloc extends Bloc<EventType, StateType> {}

class TimerBloc extends BaseBloc {
  @override
  StateType get initialState => // ...

  @override
  Stream<StateType> mapEventToState(EventType event) async* {
    // ...
  }
}

class AnotherBloc extends BaseBloc {
  @override
  StateType get initialState => // ...

  @override
  Stream<StateType> mapEventToState(EventType event) async* {
    // ...
  }
}

class TimerField extends StatelessWidget {
  final BaseBloc bloc;

  const TimerField({
    Key key,
    @required this.bloc,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return BlocBuilder<BaseBloc, StateType>(
      bloc: bloc,
      builder: ....
    );
  }