title: How to know when a view is actually displayed
body: <p>I have a Gallery that displays multiple scrollable frames, each containing a complex layout.
  One of these layout elements is a gauge-like custom view that should animate whenever it gets displayed - not just created.
  So if I scroll to the layout containing this view once, then go back, then scroll there again - it should do its animation and the user should see it.</p>
  
  <p>I didn't find an appropriate callback for that. What I've already tried is overriding:</p>
  
  <p>onDraw</p>
  
  <p>onLayout</p>
  
  <p>onAttachedToWindow</p>
  
  <p>onDisplayHint</p>
  
  <p>onVisibilityChanged</p>
  
  <p>Some of them are not called at all, and some are called only when the Gallery re-initializes the view - not when it is actually displayed.</p>
  
  <p>Thank ahead!</p>