更改flutter BLoC中的placeID后数据未更新

Question

我正在与 BLoC 合作一个项目。我已经制作了一些类来更新数据。 一旦你传递了 placeID，数据就会出现。 但是，一旦您第一次传递 PlaceID，它将更新数据和小部件。 但是一旦我通过新的 placeID 旧数据就不会更新。它显示旧数据。

所有代码文件：

RestaurantDetailBloc.dart

class RestaurantDetailBloc extends Bloc<RestaurantDetailEvent, RestaurantDetailState> {
  static final RestaurantDetailBloc _restaurantDetailBlocSingleton = new RestaurantDetailBloc._internal();
  factory RestaurantDetailBloc() {
    return _restaurantDetailBlocSingleton;
  }
  RestaurantDetailBloc._internal();
  RestaurantDetailState get initialState => new UnRestaurantDetailState();
  @override
  Stream<RestaurantDetailState> mapEventToState(
    RestaurantDetailEvent event,
  ) async* {
    try {
      yield await event.applyAsync(currentState: currentState, bloc: this);
    } catch (_, stackTrace) {
      print('$_ $stackTrace');
      yield currentState;
    }
  }
}

LoadRestaurantDetailEvent.dart

@immutable
abstract class RestaurantDetailEvent {
  Future<RestaurantDetailState> applyAsync(
      {RestaurantDetailState currentState, RestaurantDetailBloc bloc});
      final RestaurantDetailProvider _provider = RestaurantDetailProvider();
}

class LoadRestaurantDetailEvent extends RestaurantDetailEvent {
  @override
  String toString() => 'LoadRestaurantDetailEvent';
   String placeID;
   LoadRestaurantDetailEvent({Key key,this.placeID});
  @override
  Future<RestaurantDetailState> applyAsync(
      {RestaurantDetailState currentState, RestaurantDetailBloc bloc}) async {
    try {
      await Future.delayed(new Duration(seconds: 2));
      var component = await _provider.getRestaurantReview(placeID); 
      print(component);
      return new InRestaurantDetailState(component);
    } catch (_, stackTrace) {
      print('$_ $stackTrace');
      return new ErrorRestaurantDetailState(_?.toString());
    }
  }
}

RestaurantDetailPage.dart

class RestaurantDetailPage extends StatelessWidget {
  static const String routeName = "/restaurantDetail";
  final String imageURL;
  final String placeID;
  const RestaurantDetailPage({Key key, this.imageURL,this.placeID}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    var _restaurantDetailBloc = new RestaurantDetailBloc();
    return  new RestaurantDetailScreen(restaurantDetailBloc: _restaurantDetailBloc,imageUrl: this.imageURL,placeId: this.placeID,);
  }
}

RestaurantDetailProvider.dart

class RestaurantDetailProvider {

String getBaseUrl(String placeID){
    final urlBase = "https://maps.googleapis.com/maps/api/place/details/json?placeid=$placeID&key=xxxxxxxxxxxxxGooglePlaceKey";
    return urlBase;
}

  Future<void> loadAsync(String token) async {
    /// write from keystore/keychain
    await Future.delayed(new Duration(seconds: 2));
  }

  Future<void> saveAsync(String token) async {
    /// write from keystore/keychain
    await Future.delayed(new Duration(seconds: 2));
  }

  Future<Map<String, dynamic>> getRestaurantReview(String placeId)async{
    var response = await http.get(getBaseUrl(placeId));
    RestaurantReviews reviews = RestaurantReviews();

    if(response.statusCode == 200){
      var decodedJson = jsonDecode(response.body);
      print(decodedJson);

      //reviews.result = decodedJson['result'];
      return decodedJson;
    }
    else{
    }

  }
}

InRestaurantDetailState.dart

@immutable
abstract class RestaurantDetailState extends Equatable {
  RestaurantDetailState([Iterable props]) : super(props);

  /// Copy object for use in action
  RestaurantDetailState getStateCopy();
}

/// UnInitialized
class UnRestaurantDetailState extends RestaurantDetailState {
  @override
  String toString() => 'UnRestaurantDetailState';

  @override
  RestaurantDetailState getStateCopy() {
    return UnRestaurantDetailState();
  }
}

class InRestaurantDetailState extends RestaurantDetailState {

final   resReview;

  InRestaurantDetailState(this.resReview);

  @override
  String toString() => 'InRestaurantDetailState';

  @override
  RestaurantDetailState getStateCopy() {
    return InRestaurantDetailState(resReview);
  }
}

class ErrorRestaurantDetailState extends RestaurantDetailState {
  final String errorMessage;

  ErrorRestaurantDetailState(this.errorMessage);

  @override
  String toString() => 'ErrorRestaurantDetailState';

  @override
  RestaurantDetailState getStateCopy() {
    return ErrorRestaurantDetailState(this.errorMessage);
  }
}

RestaurantDetailScreenState.dart

class RestaurantDetailScreen extends StatefulWidget {
  const RestaurantDetailScreen({
    Key key,
    @required RestaurantDetailBloc restaurantDetailBloc,
    this.imageUrl, this.placeId,
  })  : _restaurantDetailBloc = restaurantDetailBloc,
        super(key: key);

  final RestaurantDetailBloc _restaurantDetailBloc;
  final String imageUrl;
  final String placeId;

  @override
  RestaurantDetailScreenState createState() {
    return new RestaurantDetailScreenState(_restaurantDetailBloc, imageUrl,placeId);
  }
}
class RestaurantDetailScreenState extends State<RestaurantDetailScreen> {
  final RestaurantDetailBloc _restaurantDetailBloc;
  final String imageUrl;
  final String placeId;

  RestaurantDetailScreenState(this._restaurantDetailBloc, this.imageUrl,this.placeId);

  @override
  void initState() {
    super.initState();

    this._restaurantDetailBloc.dispatch(LoadRestaurantDetailEvent(placeID:placeId));
  }

  @override
  void dispose() {
    super.dispose();
  }
@override
  Widget build(BuildContext context) {
    SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle.dark);
    final width = MediaQuery.of(context).size.width;
    final height = MediaQuery.of(context).size.height;

    return BlocBuilder<RestaurantDetailBloc, RestaurantDetailState>(
        bloc: widget._restaurantDetailBloc,
        builder: (
          BuildContext context,
          var currentState,
        ) {
          if (currentState is UnRestaurantDetailState) {
            return MaterialApp(
                home: new Scaffold(
              body: new Container(
                color: Colors.white,
                child: Center(
                  child: CircularProgressIndicator(),
                ),
              ),
            ));
          }
          if (currentState is ErrorRestaurantDetailState) {
            return new Container(
                child: new Center(
              child: new Text(currentState.errorMessage ?? 'Error'),
            ));
          }
          if (currentState is InRestaurantDetailState) {
            var resList = currentState.resReview;
            print(resList);

            return MaterialApp(
              home: new Scaffold(
)
);
}

请帮帮我，我已经度过了一整天。 提前谢谢你。

Answer 1

您需要将数据传递给父类进行比较。这就是我们使用 equatable 的原因。进行这些更改，它应该可以工作。如果没有，请告诉我。

class InRestaurantDetailState extends RestaurantDetailState {

 final   resReview;

 //You need to change this line to
 InRestaurantDetailState(this.resReview):super([resReview]);

 @override
 String toString() => 'InRestaurantDetailState';

 @override
 RestaurantDetailState getStateCopy() {
  return InRestaurantDetailState(resReview);
 }
}