This week's book giveaway is in the Design forum. We're giving away four copies of Experimentation for Engineers: From A/B testing to Bayesian optimization and have David Sweet on-line! See this thread for details.
Android uses Java so it should be pretty easy dude.
Once you get the hang of the activity/fragment lifecycle, know what widgets you can use and understand how to use database cursors, you'll have covered a sizeable amount of beginner Android.
I'd liken it to learning Rails if you already knew Ruby, as despite it not being a web app, it is kinda MVP/C.
Yea, our book is really tailored towards people like you (with Java experience). The book is the foundation for the Android class that we teach, so we've seen what it's like for hundreds (thousands?) of people to work through it. We use the feedback from our class to iterate and improve the book to make it as easy to pick up as possible.