Question

对于我的应用程序，我使用包audioplayers（https://pub.dev/packages/audioplayers），当我启动音频并从有状态的小部件返回时，我遇到的问题是这样的错误：未处理的异常：错误的状态：调用后无法添加新事件关闭，当我回去时，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，有人可以帮我吗。

    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

“从有状态的小部件返回”后，它将处理；

它将呼叫

@override
void dispose()

您调用_audioPlayer.dispose();的位置，我猜是在那之后，您仍然尝试使用_audioPlayer，但是它已经关闭了

有两种方法可以解决该问题

创建新实例_audioPlayer并对其进行处理
将_audioPlayer保存在App之类的小部件中，这样当用户在应用程序中时，您将始终将其保持“活动状态”

Ps。再次出现的问题是，_audioPlayer被销毁后，您仍然尝试使用它。

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

1 个答案: