/*
  * Called when participant leaves the room
  */
 private void removeParticipant(Participant participant) {
   videoStatusTextView.setText("Participant " + participant.getIdentity() + " left.");
   if (!participant.getIdentity().equals(participantIdentity)) {
     return;
   }
   /*
    * Show local video in primary view
    */
   thumbnailVideoView.setVisibility(View.GONE);
   localVideoTrack.removeRenderer(thumbnailVideoView);
   primaryVideoView.setMirror(true);
   localVideoTrack.addRenderer(primaryVideoView);
   localVideoView = primaryVideoView;
 }
 /*
  * Called when participant joins the room
  */
 private void addParticipant(Participant participant) {
   /*
    * This app only displays video for one additional participant per Room
    */
   if (thumbnailVideoView.getVisibility() == View.VISIBLE) {
     Snackbar.make(
             connectActionFab,
             "Multiple participants are not currently support in this UI",
             Snackbar.LENGTH_LONG)
         .setAction("Action", null)
         .show();
     return;
   }
   participantIdentity = participant.getIdentity();
   videoStatusTextView.setText("Participant " + participantIdentity + " joined");
   /*
    * Stop rendering local video track in primary view and move it to thumbnail view
    */
   localVideoTrack.removeRenderer(primaryVideoView);
   thumbnailVideoView.setVisibility(View.VISIBLE);
   localVideoTrack.addRenderer(thumbnailVideoView);
   localVideoView = thumbnailVideoView;
   /*
    * Start listening for participant media events
    */
   participant.getMedia().setListener(mediaListener());
 }