My suggestion to you, is to watch the "Navigation anti patterns" video from the wonderful series "Android design in action".
https://www.youtube.com/watch?v=Sww4omntVjs&list=PLWz5rJ2EKKc8j2B95zGMb8muZvrIy-wcF
And the slides can be found here: https://plus.google.com/u/0/photos/+NickButcher/albums/5981768132040708401
They actually talk about and demonstrate do's and dont's for Android app navigation. And this is from guys at Google that work with this every day. Very helpful!