https://github.com/gartnera/headunit for the latest code. The source here is no longer current.UPDATE: Please refer to
Unofficial Mazda Connect (tm) (*) Android Auto Headunit App
Unofficial port of Android Auto Headunit App to Mazda Connect CMU. The app makes extensive use of jni functions that were originally developed by Mike Reid as part of his Android app (see below). The Mazda specific source code is under the /mazda folder.
See the Mazda3 Revolution thread for details.
(*) - Mazda and Mazda Connect are trademarks of Mazda NA
Headunit for Android Auto (tm)
A new car or a $600+ headunit is NOT required to enjoy the integration and distraction reduced environment of Android Auto.
This headunit app can turn a Android 4.1+ tablet supporting USB Host mode into a basic Android Auto compatible headunit.
Current release is highly experimental. Some features, such as voice input and phone calls, are not yet supported.
The Headunit app should only be used for testing at this time. Do not use while driving. You assume all responsibility.
MUCH more info and ask any question on my XDA thread: http://forum.xda-developers.com/general/paid-software/android-4-1-headunit-android-auto-t3125252/
Latest June 16 Release #5 APK here: http://forum.xda-developers.com/showpost.php?p=61422602&postcount=163
Android, Google Play, Google Maps, Google Play Music and Android Auto are trademarks of Google Inc.