title: How can I tell if a UIView is in front (visible)?
body: <p>I need to detect which view is in front (currently visible).  How can I do this?</p>
  
  <p>Here is a what I would like to do:</p>
  
  <pre><code>if ( ! &lt;&lt;methodToTellIfViewAIsInFront&gt;&gt;) {
    [viewA prepareToDisplay];
    [window bringSubviewToFront: viewA];
  }
  </code></pre>