Implementation of hidden interface RemoteControlDisplay

I need a working implementation of the hidden interface IRemoteControlDisplay. The app should not be pretty, the important thing is that it works. My expectations: Working buttons for play, pause, next, previous. Metadata for what's playing. Album art for what's playing. I should be able to start a supported music player (Spotify, Rdio etc), begin playback and then open the app you've built and it should be filled with information about what's currently playing on the music player and the buttons should control the playback. You should: Have worked with stuff that's marked as hidden in the Android source before.