Android: How to get a custom view to redraw partially?

Question

I have a custom view that fills my entire screen. (A piano keyboard) When a user touches the key, it causes invalidate() to be called and the whole keyboard get

Answer 1

To complement Peterdk's answer, you could save your operations in a Picture instead of a Bitmap.

• A Bitmap will save all pixels, like he said it could take a lot of memory.
• A Picture will save the calls, like drawRect, drawLine, etc.

It depends of what is really heavy in your application : a lot of draw operations, a few draw operations but controlled by heavy calculations, a lot of blank/unused space (prefer Picture) etc...