import com.google.android.exoplayer2.trackselection.FixedTrackSelection; //导入依赖的package包/类
@Override
protected TrackSelection[] selectTracks(RendererCapabilities[] rendererCapabilities,
    TrackGroupArray[] rendererTrackGroupArrays, int[][][] rendererFormatSupports)
    throws ExoPlaybackException {
  Assertions.checkState(rendererCapabilities[VIDEO_RENDERER_INDEX].getTrackType()
      == C.TRACK_TYPE_VIDEO);
  Assertions.checkState(rendererCapabilities[AUDIO_RENDERER_INDEX].getTrackType()
      == C.TRACK_TYPE_AUDIO);
  Assertions.checkState(rendererTrackGroupArrays[VIDEO_RENDERER_INDEX].length == 1);
  Assertions.checkState(rendererTrackGroupArrays[AUDIO_RENDERER_INDEX].length == 1);
  TrackSelection[] selections = new TrackSelection[rendererCapabilities.length];
  selections[VIDEO_RENDERER_INDEX] = new RandomTrackSelection(
      rendererTrackGroupArrays[VIDEO_RENDERER_INDEX].get(0),
      getVideoTrackIndices(rendererTrackGroupArrays[VIDEO_RENDERER_INDEX].get(0),
          rendererFormatSupports[VIDEO_RENDERER_INDEX][0], videoFormatIds,
          canIncludeAdditionalVideoFormats),
      0 /* seed */);
  selections[AUDIO_RENDERER_INDEX] = new FixedTrackSelection(
      rendererTrackGroupArrays[AUDIO_RENDERER_INDEX].get(0),
      getTrackIndex(rendererTrackGroupArrays[AUDIO_RENDERER_INDEX].get(0), audioFormatId));
  includedAdditionalVideoFormats =
      selections[VIDEO_RENDERER_INDEX].length() > videoFormatIds.length;
  return selections;
}
 

import com.google.android.exoplayer2.trackselection.FixedTrackSelection; //导入依赖的package包/类
public void setSelectedTrack(@NonNull RendererType type, int index) {
    // Retrieves the available tracks
    int exoPlayerTrackIndex = getExoPlayerTrackType(type);
    MappingTrackSelector.MappedTrackInfo mappedTrackInfo = trackSelector.getCurrentMappedTrackInfo();
    TrackGroupArray trackGroupArray = mappedTrackInfo == null ? null : mappedTrackInfo.getTrackGroups(exoPlayerTrackIndex);
    if (trackGroupArray == null || trackGroupArray.length == 0) {
        return;
    }

    // Creates the track selection override
    int[] tracks = new int[] {index};
    TrackSelection.Factory factory = tracks.length == 1 ? new FixedTrackSelection.Factory() : adaptiveTrackSelectionFactory;
    MappingTrackSelector.SelectionOverride selectionOverride = new MappingTrackSelector.SelectionOverride(factory, exoPlayerTrackIndex, tracks);

    // Specifies the correct track to use
    trackSelector.setSelectionOverride(exoPlayerTrackIndex, trackGroupArray, selectionOverride);
}
 

import com.google.android.exoplayer2.trackselection.FixedTrackSelection; //导入依赖的package包/类
ExoPlayerTwoImpl create(Context context, DrmSessionCreator drmSessionCreator, boolean downgradeSecureDecoder) {
    DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
    DefaultDataSourceFactory defaultDataSourceFactory = new DefaultDataSourceFactory(context, "user-agent", bandwidthMeter);
    MediaSourceFactory mediaSourceFactory = new MediaSourceFactory(defaultDataSourceFactory, handler);

    TrackSelection.Factory adaptiveTrackSelectionFactory = new AdaptiveTrackSelection.Factory(bandwidthMeter);
    DefaultTrackSelector trackSelector = new DefaultTrackSelector(adaptiveTrackSelectionFactory);

    MediaCodecSelector mediaCodecSelector = downgradeSecureDecoder
            ? SecurityDowngradingCodecSelector.newInstance()
            : MediaCodecSelector.DEFAULT;

    ExoPlayerTrackSelector exoPlayerTrackSelector = ExoPlayerTrackSelector.newInstance(trackSelector);
    FixedTrackSelection.Factory trackSelectionFactory = new FixedTrackSelection.Factory();
    ExoPlayerAudioTrackSelector exoPlayerAudioTrackSelector = new ExoPlayerAudioTrackSelector(exoPlayerTrackSelector, trackSelectionFactory);
    ExoPlayerVideoTrackSelector exoPlayerVideoTrackSelector = new ExoPlayerVideoTrackSelector(exoPlayerTrackSelector, trackSelectionFactory);
    ExoPlayerSubtitleTrackSelector exoPlayerSubtitleTrackSelector = new ExoPlayerSubtitleTrackSelector(
            exoPlayerTrackSelector,
            trackSelectionFactory
    );

    ExoPlayerCreator exoPlayerCreator = new ExoPlayerCreator(context, trackSelector);
    RendererTypeRequesterCreator rendererTypeRequesterCreator = new RendererTypeRequesterCreator();
    ExoPlayerFacade exoPlayerFacade = new ExoPlayerFacade(
            mediaSourceFactory,
            exoPlayerAudioTrackSelector,
            exoPlayerSubtitleTrackSelector,
            exoPlayerVideoTrackSelector,
            exoPlayerCreator,
            rendererTypeRequesterCreator);

    PlayerListenersHolder listenersHolder = new PlayerListenersHolder();
    ExoPlayerForwarder exoPlayerForwarder = new ExoPlayerForwarder();
    LoadTimeout loadTimeout = new LoadTimeout(new SystemClock(), handler);
    Heart heart = Heart.newInstance(handler);

    return new ExoPlayerTwoImpl(
            exoPlayerFacade,
            listenersHolder,
            exoPlayerForwarder,
            loadTimeout,
            heart,
            drmSessionCreator,
            mediaCodecSelector
    );
}
 

import com.google.android.exoplayer2.trackselection.FixedTrackSelection; //导入依赖的package包/类
@Provides
static TrackSelection.Factory provideTrackSelectionFactory() {
    return new FixedTrackSelection.Factory();
}
 

import com.google.android.exoplayer2.trackselection.FixedTrackSelection; //导入依赖的package包/类
public QueuedExoPlayer(Context context) {
    mContext = context;
    mState = ExoPlayerState.IDLE;
    mQueue = Collections.emptyList();

    TrackSelector trackSelector = new DefaultTrackSelector(new FixedTrackSelection.Factory());
    LoadControl loadControl = new DefaultLoadControl();
    SimpleExoPlayer baseInstance = ExoPlayerFactory.newSimpleInstance(mContext,
            trackSelector, loadControl);
    mExoPlayer = new EqualizedExoPlayer(context, baseInstance);


    mExoPlayer.addListener(new ExoPlayer.EventListener() {
        @Override
        public void onLoadingChanged(boolean isLoading) {
            Timber.i("onLoadingChanged (%b)", isLoading);
        }

        @Override
        public void onPlayerStateChanged(boolean playWhenReady, int playbackState) {
            Timber.i("onPlayerStateChanged");
            QueuedExoPlayer.this.onPlayerStateChanged(playbackState);
        }

        @Override
        public void onTimelineChanged(Timeline timeline, Object manifest) {
            Timber.i("onTimelineChanged");
            QueuedExoPlayer.this.onTimelineChanged();
        }

        @Override
        public void onTracksChanged(TrackGroupArray trackGroups,
                                    TrackSelectionArray trackSelections) {
            Timber.i("onTracksChanged");
        }

        @Override
        public void onPlayerError(ExoPlaybackException error) {
            Timber.i("onPlayerError");
            QueuedExoPlayer.this.onPlayerError(error);
        }

        @Override
        public void onPositionDiscontinuity() {
            Timber.i("onPositionDiscontinuity");
            QueuedExoPlayer.this.onPositionDiscontinuity();
        }
    });
}