It's no secret that Google advocates developing apps with multiple form factors in mind. While not all the apps in Google's own portfolio are quite up to speed on this front, apps like the ones in Google's Play suite have done a nice job so far in supporting phones and tablets alike.
But since I/O 2014, Google's been working on more than just phones and tablets. Last year saw the introduction of Android for TVs, watches, and even cars, so now is the time for developers to start thinking about how their experiences will look and feel on those new form factors.
To that end, Google has announced a new reference sample app - a music player - that's available for developers to play with. The app is compatible with Android Auto, Android Wear, and Google Cast devices along with phones and tablets, of course.
The music player may be bare-bones, but it does make use of some of Lollipop's new features like MediaStyle notifications, which allow users to interact with media playback in a specially styled expandable notification.
Interested developers can grab the reference app (Universal Music Player) on Github, or read the Android Developers blog post linked below. It's worth noting though that Google's reference app is geared toward API 21+.
- Android Developers Blog