Not in Kansas Anymore
Mark Murphy, founder of CommonsWare, is the author of The Busy Coder's Guide to Android Development, the first, largest, and most up-to-date book on Android app programming, covering Android Studio and the latest Android SDKs. This book gets updated every ~8 weeks, with subscribers getting access to those updates. The latest update, Version 7.1, added coverage of the data binding framework, Volley, and LeakCanary, as part of its 3,640 pages.
He also offers office hours chats and training on Android app development, in case you are interested in help beyond what fits the Stack Overflow model.
Heck, he even has a blog.
All code in Stack Overflow questions, answers, or comments written by Mark Murphy are hereby licensed under the Apache Software License 2.0, unless otherwise noted where that code appears on Stack Overflow. Some of that code comes from his book's GitHub repo or various other CommonsWare open source projects.