// 1. Create a default TrackSelector
BandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
TrackSelection.Factory videoTrackSelectionFactory = new AdaptiveVideoTrackSelection.Factory(bandwidthMeter);
TrackSelector trackSelector = new DefaultTrackSelector(videoTrackSelectionFactory);
// 2. Create a default LoadControl
LoadControl loadControl = new DefaultLoadControl();
// 3. Create the player
SimpleExoPlayer player =
    ExoPlayerFactory.newSimpleInstance(context, trackSelector, loadControl);

// Measures bandwidth during playback. Can be null if not required.
DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
// Produces DataSource instances through which media data is loaded.
DataSource.Factory dataSourceFactory = new DefaultDataSourceFactory(this,
    Util.getUserAgent(this, "yourApplicationName"), bandwidthMeter);
// Produces Extractor instances for parsing the media data.
ExtractorsFactory extractorsFactory = new DefaultExtractorsFactory();
// This is the MediaSource representing the media to be played.
MediaSource videoSource = new ExtractorMediaSource(mp4VideoUri,
    dataSourceFactory, extractorsFactory, null, null);
// Prepare the player with the source.
player.prepare(videoSource);

MediaSource videoSource = new ExtractorMediaSource(videoUri, dataSourceFactory, extractorsFactory, null, null);
Format format = Format.createTextSampleFormat(null, MimeTypes.APPLICATION_TTML, null, Format.NO_VALUE, Format.NO_VALUE, "en", null);
MediaSource subtitleSource = new SingleSampleMediaSource(subtitleUri, dataSourceFactory, format, C.TIME_UNSET);
MergingMediaSource mergedSource = new MergingMediaSource(videoSource, subtitleSource);        

MediaSource source = new ExtractorMediaSource(videoUri, ...);
// Loops the video indefinitely.
LoopingMediaSource loopingSource = new LoopingMediaSource(source);
// Plays the video twice.
LoopingMediaSource loopingSource = new LoopingMediaSource(source,2);

MediaSource firstSource = new ExtractorMediaSource(firstVideoUri, ...);
MediaSource secondSource = new ExtractorMediaSource(secondVideoUri, ...);
// Plays the first video, then the second video.
ConcatenatingMediaSource concatenatedSource = new ConcatenatingMediaSource(firstSource, secondSource);

public interface ExoPlayer {

  interface EventListener {

    /**
     * Called when the timeline and/or manifest has been refreshed.
     * <p>
     * Note that if the timeline has changed then a position discontinuity may also have occurred.
     * For example the current period index may have changed as a result of periods being added or
     * removed from the timeline. The will <em>not</em> be reported via a separate call to
     * {@link #onPositionDiscontinuity()}.
     *
     * @param timeline The latest timeline. Never null, but may be empty.
     * @param manifest The latest manifest. May be null.
     */
    void onTimelineChanged(Timeline timeline, Object manifest);

    /**
     * Called when the available or selected tracks change.
     *
     * @param trackGroups The available tracks. Never null, but may be of length zero.
     * @param trackSelections The track selections for each {@link Renderer}. Never null and always
     *     of length {@link #getRendererCount()}, but may contain null elements.
     */
    void onTracksChanged(TrackGroupArray trackGroups, TrackSelectionArray trackSelections);

    /**
     * Called when the player starts or stops loading the source.
     *
     * @param isLoading Whether the source is currently being loaded.
     */
    void onLoadingChanged(boolean isLoading);

    /**
     * Called when the value returned from either {@link #getPlayWhenReady()} or
     * {@link #getPlaybackState()} changes.
     *
     * @param playWhenReady Whether playback will proceed when ready.
     * @param playbackState One of the {@code STATE} constants defined in the {@link ExoPlayer}
     *     interface.
     */
    void onPlayerStateChanged(boolean playWhenReady, int playbackState);

    /**
     * Called when an error occurs. The playback state will transition to {@link #STATE_IDLE}
     * immediately after this method is called. The player instance can still be used, and
     * {@link #release()} must still be called on the player should it no longer be required.
     *
     * @param error The error.
     */
    void onPlayerError(ExoPlaybackException error);

    /**
     * Called when a position discontinuity occurs without a change to the timeline. A position
     * discontinuity occurs when the current window or period index changes (as a result of playback
     * transitioning from one period in the timeline to the next), or when the playback position
     * jumps within the period currently being played (as a result of a seek being performed, or
     * when the source introduces a discontinuity internally).
     * <p>
     * When a position discontinuity occurs as a result of a change to the timeline this method is
     * <em>not</em> called. {@link #onTimelineChanged(Timeline, Object)} is called in this case.
     */
    void onPositionDiscontinuity();

  }

Stetho.initializeWithDefaults(this);

OkHttpClient okHttpClient = new OkHttpClient.Builder()
        .addNetworkInterceptor(new StethoInterceptor())
        .build();

DataSource.Factory dataSourceFactory =
        new OkHttpDataSourceFactory(okHttpClient, userAgent, bandwidthMeter);