title: SeekBar ascending and descending
body: <p>Is it possible to make a SeekBar in Android with a descending value when I go left and ascending value when I go right?</p>
  
  <p>My idea is to have a SeekBar from 0 to 100. It will start in the middle at 50.</p>
  
  <p>So far, I had no problem.</p>
  
  <p>But I want to subtract the value with the SeekBar when the progress is descending and to add the value when the progress is ascending.</p>
  
  <p>Can you tell me if this is possible with the standard android Seekbar?</p>