title: How to change UIProgressView color while Progress Changes
body: <p>I want to change my UIProgressView progress color while the progress changes. So basically it starts white and goes getting blue while it approaches the end.</p>
  
  <p>here's my code:</p>
  
  <pre><code>-(void)changeSendProgProgress:(float)progress
  {
  
  
      CGFloat redBlueValue = 255 - (255*progress);
  
      UIColor *colorProg = [UIColor colorWithRed:redBlueValue green:redBlueValue blue:255 alpha:1.0];
  
      [sendProgress setProgressTintColor:colorProg];
      [sendProgress setProgress:progress];
  
  
  }
  </code></pre>
  
  <p>the only problem is that the progress color doesn't change, it stays white all the way to the end.
  Why it doesn`t change? 
  Should I use a UIThreading like  dispatch_async(dispatch_get_main_queue() ?</p>