Animate seekbar progress

Question

I have a screen with 4 seek bars ( As shown in the image below) . If the user moves B,C or D I calculate the average of the three and setProgress of A to the average. That was the easy part . What I would like to do is animate the progress bar A such that it does not jump in one shot (for eg from 25-75 ).

What are the recommended ways to animate A? I got a simple animation up but I am calling a TimerTask every 50ms to increment or decrement A by a unit value till I reach the required position. But its not very efficient.

Note: I have a custom Seekbar object using which I have created seekBar's A,B,C & D. Sorry I cant really share the code but will be happy to clarify anything.