title: How to make a subview automatically resize with its superview?
body: <p>I have a view which contains one sub-view; this sub-view itself contains another sub-view, which is meant to be slightly smaller than its superview.</p>
  
  <p>I am creating the first subview full-screen size then shrinking it to a very small size on the screen.  When the subview is tapped, I animate it from its small size to full-screen.</p>
  
  <p>The problem is that my second subview never resizes itself during this animation - it is always rendered full-size and overflows the bounds of its superview.</p>
  
  <p>Is there a simple way to get a subview to keep itself sized proportionally as its superview changes size?</p>