title: Replicating iOS7 Messages App UIKitDynamics with CollectionView
body: <p>I know there are lots and lots of tutorials and discussions out there on how to implement a bouncy collectionViewLayout using UIKitDynamics.</p>
  
  <p>There is even a WWDC 13 Session video addressing the exact topic of replicating the "message bubbles" in the iOS7 Messages App.</p>
  
  <p>I created my own "bouncy layout" following the session video and using <a href="http://www.teehanlax.com/blog/implementing-a-bouncy-uicollectionviewlayout-with-uikit-dynamics/">this tutorial</a> which also provides the details on implementing a tiling mechanism, which makes sure things are running smoothly even with thousands of cells.</p>
  
  <p>However, the result still is very different from what we can see in the Messages App and my goal was to replicate the EXACT SAME BEHAVIOR as the messages app.</p>
  
  <ol>
  <li>No matter how many different values i provide for the <code>UIAttachmentBehavior</code> properties (length, damping, frequency), I can't get the  bouncing right.
  <br>The session video says that setting a value > 0 for length breaks things, because the cells would not return to their actual position. However, i could only reproduce the smooth and fast decelerating the Messages App shows by setting ~0.5 for length ?</li>
  <li>When the collectionView reaches it's bounds ends there is a nice exaggerated bounce for the last few bubbles in the Messages App where my "tutorial implementation" just doesn't bounce at all.</li>
  </ol>
  
  <p>There is a discussion in the developer forums : <a href="https://devforums.apple.com/message/891070#891070">Apple Dev Forums Discussion</a></p>
  
  <p>Some suggest using multiple UIAttachmentBehaviors per Cell, others say applying UIView - spring Animations can give you this desired effect. There is even the assumption that the Messages App does not use UIKitDynamics + UICollectionView at all. (i doubt that Apple is not using this obvious technique for that)</p>
  
  <p>So my question: Has anyone successfully implemented an exact replication of the Message bubbles behavior ? What more can i do to get answers regarding this topic ?</p>