How can me and my friend start developing android apps?

My friend and I would like to start developing software and plan on starting by developing Android apps. We don't know anything about writing programs though and want to know what we should learn first? Should we learn how to use the Android sdk? or should we start learning how to write code first? When we do learn to write code, i know that Android apps use Java but I don't know if we should start off by learning to write in Java. How do you recommend we start this?