By Alvin Alexander. Last updated: June 4, 2016
Google has a nice Android UI design guidelines section on the Android website. As I'm working on a new Android tablet application, I keep looking back at this section, and these are the most relevant pages for me:
This one isn't quite as important to me, but if you want to create an Android app that looks nice, it is a nice color palette:
They also have a downloads page here:
As a side note, if you're working with Android tab layouts, this page on a different section of their website is also helpful: