在 xamarin 中使用 Exoplayer 的自定义渲染器进行导航

Question

我在主页中有一个列表视图，当我单击列表视图时，它会转到第二页，其中有 Exoplayer 与自定义渲染器集成，所以问题是如何正确释放播放器，因为当前 _player 始终等于 null，多个播放音频，如果从第一页导航到第二页多次。

这是自定义渲染器的代码-

public class VideoPlayerRenderer : ViewRenderer<VideoPlayer, SimpleExoPlayerView>, IExoPlayerEventListener
{
    private SimpleExoPlayerView _playerView;
    private SimpleExoPlayer _player;
    private DefaultTrackSelector trackSelector;
    DefaultHttpDataSourceFactory defaultHttpDataSourceFactory;
    DefaultDataSourceFactory defaultDataSourceFactory ;
    ExtractorMediaSource extractorMediaSource ;
    public VideoPlayerRenderer(Context context) : base(context)
    {

    }


    protected override void OnElementChanged(ElementChangedEventArgs<VideoPlayer> e)
    {
        base.OnElementChanged(e);

        if (_player == null)
        {
            InitializePlayer();
        }


        Play();
    }


    private void InitializePlayer()
    {

        trackSelector = new DefaultTrackSelector();

        _player = ExoPlayerFactory.NewSimpleInstance(Context,trackSelector);
        _player.PlayWhenReady = true;
        _playerView = new SimpleExoPlayerView(Context) { Player = _player };
        SetNativeControl(_playerView);
        SetBackgroundColor(Android.Graphics.Color.Green);
    }

    private void Play()
    {

            Uri sourceUri = Uri.Parse(Element.SourceUrl);
            var mediaUri = Android.Net.Uri.Parse(Element.SourceUrl);
            var userAgent = Util.GetUserAgent(Context, "App1");
             defaultHttpDataSourceFactory = new DefaultHttpDataSourceFactory(userAgent);
             defaultDataSourceFactory = new DefaultDataSourceFactory(Context, null, defaultHttpDataSourceFactory);
             extractorMediaSource = new ExtractorMediaSource(mediaUri, defaultDataSourceFactory, new DefaultExtractorsFactory(), null, null);
            _player.Prepare(extractorMediaSource);
            _player.AddListener(this);

    }

Answer 1

在您的自定义渲染器中，覆盖 OnDetachedFromWindow 以停止播放器：

   protected override void OnDetachedFromWindow()
    {
        base.OnDetachedFromWindow();
        _player.Stop();
        _player.Release();
    }

参考：onDetachedFromWindow

更新：

要控制播放器，您应该创建一个 SimpleExoPlayer 单例，确保整个项目中只有一个 _player：

class ExoPlayerInstance
{

    private static SimpleExoPlayer _player;

    public static SimpleExoPlayer player
    {
        get
        {
            if (_player == null)
            {
                _player = ExoPlayerFactory.NewSimpleInstance(Application.Context, new DefaultTrackSelector());
                _player.PlayWhenReady = true;
            }
            return _player;
        }
    }
}

然后在您的自定义渲染中，删除InitializePlayer 部分并使用ExoPlayerInstance：

protected override void OnElementChanged(ElementChangedEventArgs<VideoPlayer> e)
{
    base.OnElementChanged(e);

    //remove the InitializePlayer part
    //if (_player == null)
    //    InitializePlayer();

    _player = ExoPlayerInstance.player;

    _playerView = new SimpleExoPlayerView(Context) { Player = _player };
    SetNativeControl(_playerView);

    if (_player.IsPlayingAd || _player.IsLoading)
    {
        //maybe something more need to do , stop() here is an example
        _player.Stop();
    }

    Play();
}