Hi nitin,
It is good to know that you are switching to Android development which has a lot of potentials. By the way I want to tell you that there is difference between learning a programming theoretically and doing it practically. In my opinion,
you should start doing a small project based on some idea in Android. As you sit for doing a project, ideas will run automatically in your mind. And as you strike upon an idea, ask the question in Google and it will throw you a list of tutorials which will give you the knowledge on how to materialize on that idea. During the reading process, the tutorial will throw some light on Android APIs which you wanted to learn. As you go on to do more projects in Android, you will be armed with the best of knowledge in it. In my opinion, theory books on Android will do no good unless you are doing it practically.
Ok. If you are really interested in buying a book I would recommend "Busy coder's guide" as it is written in a clear manner.