FYI, while searching for Android libraries I came across the Android Arsenal site[1], which is a directory of libraries for Android. Warning: I admit it got me a bit sidetracked because of all the interesting links there. On there it also has some best practices and pattern links. One of the many I like is [2]. My Design layout attributes patch[3] was inspired by it. I couldn't resist.
-Bernd
[1] https://android-arsenal.com/demo?sort=rating [2] https://github.com/futurice/android-best-practices [3] https://gerrit.wikimedia.org/r/#/c/194263/