flutter - 我在Flutter上的流控制器上遇到错误(I am getting error on stream controller on flutter)

Question

When I open the app it opens, when I click on the image it opens but when I press back n again click on the image it throws an exception saying

(当我打开应用程序时，它会打开，当我单击图像时，它会打开，但是当我再次按n键时，它将引发异常，)

"Stream has already listened to".

(“流已经听过”。)

Here is my code:

(这是我的代码：)

    StreamSubscription<T> _subscribe(void onData(T data), Function onError,
      void onDone(), bool cancelOnError) {
    if (!_isInitialState) {
      throw new StateError("Stream has already been listened to."); //here I get the exception
    }
    _ControllerSubscription<T> subscription = new _ControllerSubscription<T>(
        this, onData, onError, onDone, cancelOnError);

    _PendingEvents<T> pendingEvents = _pendingEvents;
    _state |= _STATE_SUBSCRIBED;

  ask by Selina translate from so

Answer 1

等待大神答复