Overdraw: Painting regions more than once

Overdraw: Painting regions more than once

If you set a background drawable on a root view, then you should use a custom theme where the theme background is null. Otherwise, the theme background will be painted first, only to have your custom background completely cover it; this is called "overdraw".

NOTE: This detector relies on figuring out which layouts are associated with which activities based on scanning the Java code, and it's currently doing that using an inexact pattern matching algorithm. Therefore, it can incorrectly conclude which activity the layout is associated with and then wrongly complain that a background-theme is hidden.

If you want your custom background on multiple pages, then you should consider making a custom theme with your custom background and just using that theme instead of a root element background.

Of course it's possible that your custom drawable is translucent and you want it to be mixed with the background. However, you will get better performance if you pre-mix the background with your drawable and use that resulting image or color as a custom theme background instead.

Issue id: Overdraw