title: can I add a uiprogressbar to a uibutton
body: <p>I want to know if it is possible to subclass UIButton someway to add another component to it such as a preloader or progress indicator.</p>
  
  <p>In pseudo code what I have in mind is something like the following.</p>
  
  <pre><code>UIButtonWithProgress *button =[[UIButtonWithProgress alloc]init]
  
  [button.progressbar setProgress:50%]
  </code></pre>