For developing Android apps, you need to know Core Java and rest of it you have to learn Android API.
For learning Java, you can try the following online resources too:
http://docs.oracle.com/javase/tutorial/
https://www.udemy.com/java-tutorial (have a free course on Java)
http://tutorialspoint.com/java/
http://www.c4learn.com/javaprogramming/
Java course on Udemy website is enough for you to get started with Android app development.
Android app development online resource:
http://developer.android.com/training/in...
First things first , learn Java. If you've never coded before , try a for dummies book so you get into the actual world of programming. there is a course on edx called cs50 and a few more for general programming , those might be a good start. If you've coded before simply look for crash course java books and generally search for tutorials on google , shouldn't be difficult to find.
