Google's Android M secret weapon: built-in theme engine

Google launched the Android M developer preview for some of its smartphones and tablets at the previous I/O conference. Now some users have discovered that the Android M developer preview has a built-in theme engine that allows users to apply different themes, but Google did not mention this feature at the I/O conference. The built-in theme engine in the Android M developer preview allows customizing the appearance of the user interface, including the colors of native apps, such as dialers and contacts, as well as the shapes and colors of all app icons.

It is said that Android M uses Sony's RRO (Runtime Resource Overlay) theme engine, which was added to the Android Open Source Project (AOSP) last year. Sony's RRO theme engine can change the appearance of an app without changing the app code. Sony is currently using this theme engine in its Xperia smartphones and tablets. However, before applying themes to the Android M developer preview, you still need to ROOT. It is hoped that when the official version of Android M is launched this fall, users will be able to apply themes without ROOT.