如何停止订阅单例类的流？

Question

如何停止订阅单例类的流，并且在重新创建订阅时不继续该流的数据？

class MyClass {
  static MyClass _instance;

  factory MyClass() {
    _instance ??= MyClass._internal();
    return _instance;
  }

  MyClass._internal();

  final BehaviorSubject<Status> _streamController = BehaviorSubject<Status>();
  Stream<Status> get stream => _streamController.stream;
  Function(Status) get sink => _streamController.sink.add;

  StreamSubscription subscriptionImage;

  void dispose() {
    _streamController?.close();
  }

  void listen() {
    subscriptionImage = stream.listen((Status statusAnalysis) async {
      if (statusAnalysis.saving) {
        try {
          await patch(statusAnalysis);
        } on MyException catch (e) {}
      }
    });
  }
}

Answer 1

只需在前面添加subscriptionImage?.cancel();

subscriptionImage = stream.listen((Status statusAnalysis){...});

并且您将确保在创建新订阅之前取消之前的订阅（如果有）。