title: iOS 7 and later: set status bar style per view controller
body: <p><br>
  I tried many ways to set the status bar style (default or lightcontent) but can't get it to work on a per view controller basis. I can set the status bar style for the whole app only.</p>
  
  <p>Does anyone have a hint?</p>
  
  <p>I tried <code>UIViewControllerBasedStatusBarAppearance</code> </p>
  
  <p>and </p>
  
  <pre><code>-(UIStatusBarStyle)preferredStatusBarStyle{ 
      return UIStatusBarStyleLightContent; 
  }
  </code></pre>
  
  <p>but these methods don't work.</p>