Since you have already experience with software development, I suggest you start with the tutorials and documentation on developer.android.com.
Apart from that, keep an eye open for a new revision of Reto Maier's "Professional Android 4 Development". Reto is head of Google's Android Developer relations team, and the book is a very detailed explanation of architecture, patterns, APIs and best practices on the platform.
The current edition is somewhat old, however. I expect a new version after L is released later this year.
Apart from that, keep an eye open for a new revision of Reto Maier's "Professional Android 4 Development". Reto is head of Google's Android Developer relations team, and the book is a very detailed explanation of architecture, patterns, APIs and best practices on the platform.
The current edition is somewhat old, however. I expect a new version after L is released later this year.