title: play a particular file from playlist with ExoPlayer 2.8
body: <p>I'm working with Exoplayer 2.8.0, I have simpleList filled with an array of streams audios, it's working fine using the notifications buttons, next, previews and stop, but if want to play a particular song from the list, it's always start with the first song on the list, it's don't matter which song of the list I clicked,  always start on the first one.</p>
  
  <p>This how I made the playlist:</p>
  
  <pre><code>// Create the Playlist from Array
      mediaSources = new MediaSource[radioList_2.size()];
      for (int i = 0; i &lt; radioList_2.size(); i++) {
          mediaSources[i] = new ExtractorMediaSource( Uri.parse(radioList_2.get(i)),
                  dataSourceFactory, extractorsFactory, null, null);
  
      }
  
      concatenatingMediaSource=new ConcatenatingMediaSource(mediaSources);
      concatenatingMediaSource.addMediaSource(concatenatingMediaSource);
      player.prepare(new ConcatenatingMediaSource(false,mediaSources));
      sTartNotification();
  </code></pre>
  
  <p>This is the code use when I click an item of the list:</p>
  
  <pre><code>  MediaSource mediaSource = new ExtractorMediaSource(Uri.parse(strUrl),
              dataSourceFactory,
              extractorsFactory,
              mainHandler,
              null);
  
  //    player.prepare(mediaSource);       
  //playerNotificationManager.setPlayer(null);
  
  
      concatenatingMediaSource.addMediaSource(mediaSource);
      player.prepare(new ConcatenatingMediaSource(true,mediaSource));
  
      sTartNotification();
      player.setPlayWhenReady(true);
  
      //concatenatingMediaSource=new ConcatenatingMediaSource(mediaSource);
      // concatenatingMediaSource.addMediaSource(0,mediaSource);
  </code></pre>
  
  <p>I have tried the comments lines too, it's start playing but then the navigation buttons stop working, it's like the playlist not longer exits.</p>
  
  <p>I have read this:<a href="https://stackoverflow.com/questions/45709105/how-to-play-a-particular-video-from-exoplayer-playlist-android">How to play a particular video from ExoPlayer playlist android?</a>
  but the seek function it's not working for me.</p>
  
  <p>Thanks, 
  help will be appreciate</p>