If you are already a programmer by trade, an excellent resource is Professional Android 4 Application Development.* It set a high bar and teaches Android in an approachable fashion.
I got my start with version 2, in the time before
Fragments and tablets. The book was updated for Ice Cream Sandwich, but a lot has changed in the last few years. Hopefully there’s a new version on the way.
Most Android books (and many online examples) don’t currently teach Android Studio. My book is based on Android Studio and walk you through on how to create a high quality app from scratch. Also, Android Programming: Pushing the Limits* could be helpful for beginners as it goes over this IDE in depth.
The developer documentation is getting better all the time and the training docs walk you through several topics. There’s also sample code for different use cases. You’ll be spending plenty of time on stackoverflow.
* Amazon affiliate links