使用 xamarin 中的 Exoplayer 自定义渲染器进行导航

Question

我在主页上有一个列表视图，当我单击列表视图时，它会转到第 2 页，其中它与自定义渲染器集成了 Exoplayer，所以问题是如何正确释放播放器，因为当前_player总是等于 null，播放多个音频，如果多次从第一页导航到第 2 页。

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的单例，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();
}