title: How can I determine if an animation is currently playing in UIView?
body: <p>I'd like to determine if a UITableView and other views are currently performing some type of animation with core animation.</p>
  
  <p>In investigating this, I discovered the following Stack Overflow question &amp; answer:
  <a href="https://stackoverflow.com/questions/5526476/how-to-tell-if-uiview-is-in-middle-of-animation">how to tell if uiview is in middle of animation?</a></p>
  
  <p>I've verified that this technique of checking the animationKeys property works great for controls like UISlider, however when attempting to check for animationKeys during a UITableView animation, the NSArray count is always 0. I even went so far as to recursively check every view and layer in the view hierarchy for animationKeys, and all of them had a count of 0.</p>
  
  <p>In looking into the addAnimation:forKey: selector of CALayer, I discovered that it's possible to add an animation with a nil key. This is probably the reason animationKeys has a count of 0. Due to this, I can't use the above linked technique.</p>
  
  <p>The question: Is it even possible to reliably determine if an animation is currently playing? If so, what are some techniques for determining this?</p>