title: iOS Change alpha of UIButton when there is an EventTouchDown
body: <p>I would like the change the alpha of a UIButton when there is an EventTouchDown on it.  I'm was hoping there was a way to do it similar to the below code:</p>
  
  <pre><code>[self.myButton setImage:&lt;#(UIImage *)#&gt; forState:UIControlEventTouchDown];
  </code></pre>
  
  <p>Is there a way to do something like this with "setAlpha"?</p>
  
  <p>Thanks you!!!</p>