Android :: What's "proper" Way To Time Animation Frames?

I have a project that requires a view to be animated whenever the user performs a certain action - perhaps twenty frames or so, with a total duration of a second. There's more work required than just updating the view, so the animation classes are not helpful.

Right now my test program uses a very simple method: I have a handler that is called to start the animation. The handler's handleMessage() method calculates the new frame, invalidates the view, and calls sendMessageDelayed(obtainMessage(0), 50); However, the animation isn't smooth - especially, for some reason, in landscape mode. Portrait mode seems much better (on a G1, if it matters).

This suggests to me that this isn't the right way to... handle... this problem. What would be a better way? Calculating time deltas? Starting a new thread whenever the animation starts and having it repeatedly calculate and invalidate instead of relying on the handler, even though it means creating and destroying a new thread every time? (most of the time the program is idle; the user interacts with it every few seconds, typically). Starting a thread and leaving it running?

Whether that's the right way or not, what's the most accurate way on Android to measure time, and to sleep for a specific duration?