How to cache mp3 files using ExoPlayer

exoPlayerCacheMp3.java

private final ExoPlayer exoPlayer;

public PlayerExoPlayer(ExoPlayer exoPlayer) {
  this.exoPlayer = exoPlayer;
}

public void prepareMp3(Context context, Uri uri) {
  DefaultBandwidthMeter defaultBandwidthMeter = new DefaultBandwidthMeter();

  String userAgent = System.getProperty("http.agent");

  DataSource.Factory dataSourceFactory = new DefaultHttpDataSourceFactory(userAgent, defaultBandwidthMeter);
  int cacheSizeInBytes = 100 * 1024 * 1024;
  LeastRecentlyUsedCacheEvictor leastRecentlyUsedCacheEvictor = new LeastRecentlyUsedCacheEvictor(cacheSizeInBytes);
  File cacheDirectory = new File(context.getCacheDir(), "exoplayer_mp3_cache");
  SimpleCache simpleCache = new SimpleCache(cacheDirectory, leastRecentlyUsedCacheEvictor);
  int maxCacheFileSize = 4 * 1024 * 1024;
  CacheDataSourceFactory cacheDataSourceFactory = new CacheDataSourceFactory(simpleCache, dataSourceFactory, CacheDataSource.FLAG_BLOCK_ON_CACHE | CacheDataSource.FLAG_IGNORE_CACHE_ON_ERROR, maxCacheFileSize);

  MediaSource mediaSource = new ExtractorMediaSource(uri, cacheDataSourceFactory, new DefaultExtractorsFactory(), null, null);

  exoPlayer.prepare(mediaSource);
}