Gradle for Android
Disclaimer: This book was written in 2015 and, as with any tech book, parts of it are obsolete by now. While most of the content is still valid, not all syntax in the book is correct in the newer versions of Gradle.
If you like my posts about Gradle, be sure to check out my book “Gradle for Android”. My main motivation for writing it was to help Android developers understand how Gradle works, how to get more out of the build system, and how to create tasks and plugins to automate the entire process. There is a great deal of information on build variants, dependency management, multi-module builds, testing, continuous integration, and more.