title: Issue with ImageButton.setVisibility()
body: <p>I'm having a problem when setting the visibility of two image buttons one on top of the other. The idea is to implement a play/pause control. The problem is that the only part where setting the visibility actually works is in the click listeners of the buttons. If I try to change it somewhere else nothing happens. Any idea why is this happening?</p>
  
  <pre><code>playBtn.setOnClickListener(new OnClickListener() {//PLAY BUTTON LISTENER
      public void onClick(View v) {
   playBtn.setVisibility(ImageButton.GONE);
   pauseBtn.setVisibility(ImageButton.VISIBLE);
   mp.start();
      }});
  
  pauseBtn.setOnClickListener(new OnClickListener() {//PAUSE BUTTON LISTENER
   public void onClick(View v) {
    pauseBtn.setVisibility(ImageButton.GONE);
    playBtn.setVisibility(ImageButton.VISIBLE);
    mp.pause();
   }});
  
  final class SeekBarTask extends TimerTask {
    public SeekBarTask(int duration) {
  
    }
    @Override
    public void run() {
     if(seekBar.getProgress() &gt;= mp.getDuration()) {//IF SONG HAS FINISHED...
      pauseBtn.setVisibility(ImageButton.GONE);//THESE ONES
      playBtn.setVisibility(ImageButton.VISIBLE);//DOESN'T WORK
      mp.stop();
     }
     else {
     seekBar.incrementProgressBy(100);
     }
    }
   }
  </code></pre>