title: Swift UIScrollview double tap uitbutton zoom
body: <p>I have a view hierarchy like this: </p>
  
  <p><code>UIView</code> -> <code>UIScrollView</code> -> <code>UIView (contentView)</code> -> <code>UIButton</code></p>
  
  <p>I have added code to the <code>UIScrollView</code> to activate zoom when the user double tap.
  This is working well, the content view and the <code>UIButton</code> are zooming.</p>
  
  <p>In my content view, I have some <code>UIButton</code>, my problem is when I double click on this button, I want the scroll view to zoom (this is ok) but I don't want my button to fire the event (this is not ok)</p>
  
  <p>I want the button to only fire an event if the user click on it one time, but not with double tap.</p>
  
  <p>In my case, the <code>UIButton</code> can be small, and I want the user to get the possibility to double tap on it to zoom, but to fire an action only if it is a one click.</p>
  
  <p>I try to do this with swift</p>
  
  <p>thanks a lot for your help </p>