title: Detecting when AppBarLayout/CollapsingToolbarLayout is completely expanded
body: <p>I have a fragment that uses the new CoordinatorLayout/AppBarLayout/CollapsingToolbarLayout paradigm, and I'd like to be able to detect when the collapsing toolbar is fully expanded so that I can perform an operation on the entire fragment it's in, e.g. popping the fragment off the stack and going to a new one, dismissing the fragment. I have the dismissing code working, I just need to know when and when not to use it.</p>
  
  <p>I've experimented a bit with <a href="https://developer.android.com/reference/android/support/design/widget/AppBarLayout.OnOffsetChangedListener.html">AppBarLayout.OnOffsetChangedListener</a>, but didn't have much luck. Is there a way to use it to determine when things are completely expanded, or is there a more preferred method someone knows about?</p>
  
  <p>Thanks in advance!</p>
  
  <p>EDIT:
  I also see there are a couple implementations for <a href="https://developer.android.com/reference/android/support/design/widget/AppBarLayout.html#setExpanded(boolean)">AppBarLayout.setExpanded(...)</a>, however not AppBarLayout.getExpanded() or something similar, so I'm stumped there too.</p>