Use player's metadata to get album art

[BrianValente]

Take a look at this:
https://github.com/BrianValente/MediaNotification/blob/master/app/src/main/java/james/medianotification/services/NotificationService.java#L402

With OnActiveSessionsChangedListener I can get every MediaController running on the device and access it's metadata, including the album art. I'm using it right now in my fork and works great with Spotify. Note that my fork only works with Spotify, this needs to be tested with more music players.

I'm interested in this project, if you need a team or just some help you can count on me.

[fennifith]

This looks great, thanks! I wasn't aware of this API before (well, I was, but I didn't know how to use it). I'll test it with a few other music players tomorrow if I get time. And yes, I'm definitely interested in teaming up on this project, I could use a bit of help with it 😀

Already working on making an 'about' page in the app that lists contributors to the project using the github API, should be done tomorrow morning.