How to use the existing animation APIs to get easy curved motion for your UIs.
In the real world, things don't move in straight lines. Moving items around on the screen should feel as natural as possible; sometimes curved motion can help.
Article "Curved Motion in Android": http://graphics-geek.blogspot.com/2012/01/curved-motion-in-android.html
Code: http://developer.android.com/shareables/devbytes/CurvedMotion.zip
