As you are no doubt aware that views in Android GUIs have many accessors defining their position, their color, and so on, wouldn't it just be simpler to animate a view by changing those parameters a little bit each frame? This feature has been introduced in Honeycomb; it's called an Animator.
At its most basic level, animators are little daemon threads that wake up, change a view a bit, and go back to sleep till the next frame. They are a lot like the old
Animation classes for tweening, but they are more generalized.
For instance, an Animator would allow you to modify the background color of a view, something that no tween could do. And if you have implemented your own views with special properties, they will work ...