未处理的异常：错误状态：调用关闭音频播放器后无法添加新事件

Question

对于我的应用程序，我使用音频播放器包 (https://pub.dev/packages/audioplayers)，而我的问题是当我启动音频并从有状态小部件返回时出现这样的错误：未处理的异常：错误状态：无法添加新事件关闭后，当我返回时，我的音频丢失了，但我无法停止音频。而且我不知道该怎么办，谁能帮帮我。

    enum PlayerState { stopped, playing, paused }
    enum PlayingRouteState { speakers, earpiece }

    class PlayerWidget extends StatefulWidget {
      final String url;
      final PlayerMode mode;

      PlayerWidget({this.url, this.mode = PlayerMode.MEDIA_PLAYER});

      @override
      State<StatefulWidget> createState() {
        return _PlayerWidgetState(url, mode);
      }
    }

    class _PlayerWidgetState extends State<PlayerWidget> {
      //audio player
      String url;
      PlayerMode mode;
      AudioPlayer _audioPlayer;
      AudioPlayerState _audioPlayerState;
      Duration _duration;
      Duration _position;

      PlayerState _playerState = PlayerState.stopped;
      PlayingRouteState _playingRouteState = PlayingRouteState.speakers;
      StreamSubscription _durationSubscription;
      StreamSubscription _positionSubscription;
      StreamSubscription _playerCompleteSubscription;
      StreamSubscription _playerErrorSubscription;
      StreamSubscription _playerStateSubscription;

      get _isPlaying => _playerState == PlayerState.playing;
      get _isPaused => _playerState == PlayerState.paused;
      get _durationText => _duration?.toString()?.split('.')?.first ?? '';
      get _positionText => _position?.toString()?.split('.')?.first ?? '';

      _PlayerWidgetState(this.url this.mode);

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

      @override
      void dispose() async {
        _audioPlayer.dispose();
        _durationSubscription?.cancel();
        _positionSubscription?.cancel();
        _playerCompleteSubscription?.cancel();
        _playerErrorSubscription?.cancel();
        _playerStateSubscription?.cancel();
        super.dispose();
      }
  void _initAudioPlayer() {
    _audioPlayer = AudioPlayer(mode: mode);
    _durationSubscription = _audioPlayer.onDurationChanged.listen((duration) {
      setState(() => _duration = duration);

      if (Theme.of(context).platform == TargetPlatform.iOS) {
        _audioPlayer.startHeadlessService();
        _audioPlayer.setNotification(
            title: name,
            artist: author,
            imageUrl: 'url',
            forwardSkipInterval: const Duration(seconds: 30), // default is 30s
            backwardSkipInterval: const Duration(seconds: 30), // default is 30s
            duration: duration,
            elapsedTime: Duration(seconds: 0));
      }
    });

    _positionSubscription =
        _audioPlayer.onAudioPositionChanged.listen((p) => setState(() {
          _position = p;
        }));

    _playerCompleteSubscription =
        _audioPlayer.onPlayerCompletion.listen((event) {
          _onComplete();
          setState(() {
            _position = _duration;
          });
        });

    _playerErrorSubscription = _audioPlayer.onPlayerError.listen((msg) {
      print('audioPlayer error : $msg');
      setState(() {
        _playerState = PlayerState.stopped;
        _duration = Duration(seconds: 0);
        _position = Duration(seconds: 0);
      });
    });

    _audioPlayer.onPlayerStateChanged.listen((state) {
      if (!mounted) return;
      setState(() {
        _audioPlayerState = state;
      });
    });

    _audioPlayer.onNotificationPlayerStateChanged.listen((state) {
      if (!mounted) return;
      setState(() => _audioPlayerState = state);
    });

    _playingRouteState = PlayingRouteState.speakers;
  }

Answer 1

在你 "go back from a stateful widget" 之后它会处理；

它将调用

@override
void dispose()

你调用 _audioPlayer.dispose(); 的地方，我的猜测是在那之后你仍然尝试使用 _audioPlayer 但它已经关闭了

有两种方法可以解决这个问题

创建新实例 _audioPlayer 并使用它
将 _audioPlayer 保存在应用程序等小部件中，这样当用户在应用程序中时，您将始终保留它'alive'

Ps。又一个问题是你在 _audioPlayer 被处理后仍然尝试使用它

未处理的异常：错误状态：调用关闭音频播放器后无法添加新事件

Unhandled Exception: Bad state: Cannot add new events after calling close Audio player

audio

dispose

flutter