title: Progress Bar on Android gets displayed after complete onClick() execution
body: <p>I have a Button, and upon pressing it, the onClick() would process user's request.  However, this takes a little time, so I would like to have a View showing "Please wait, processing..." immediately upon pressing this Button, while its OnClickListener does its thing.  </p>
  
  <p>My problem is, this "Please wait, processing..." which I placed at the very beginning of onClick(), only appears AFTER the whole onClick() is done.  In other words, after the whole processing is done.  So, I was wondering, how do I make a View saying "Please wait, processing..." before the actual processing has begun?</p>