Building Android UIs with Custom Views

Code optimization

Allocating objects is not the only thing we should take into consideration when thinking about performance in our custom view. The amount of calculations, the type of calculations, the amount of primitives we are drawing, the amount of overdrawing, and the list of things we should check, is pretty big. In the end, most things are common sense: just don't recalculate values that we already have and maximize parts of the code that can be skipped if there are no changes required or, basically, try to reuse as much as possible what has been calculated on previous frames.

Let's compare two methods that convert YUV pixel data to RGB. It is not the most typical thing you'll have to do in a custom view, but it's perfect to show ...