title: How to hide/show thumb in a SeekBar
body: <p>I'm trying to hide the thumb of seekBar by default and show it if you touch the seekbar for the first time, but I can't make the thumb invisible.
  I tried:</p>
  
  <ul>
  <li><a href="https://stackoverflow.com/a/20855816/5479029">https://stackoverflow.com/a/20855816/5479029</a> but then I can see a white gap instead of the thumb</li>
  <li><a href="https://stackoverflow.com/a/43145751/5479029">https://stackoverflow.com/a/43145751/5479029</a> but then the thumb is placed in a wrong place when I try to make it visible again and use this <code>mySeekBar.setThumbOffset(0);</code> </li>
  <li><code>seekbar.getThumb.setVisible(false, false)</code> - it doesn't work as well</li>
  </ul>
  
  <p>How can I do that?</p>