This is an open source project I created at:
MusicMe current version gets Google Play song, album and artist information using the Unofficial Google Music API at https://github.com/jkiddo/gmusic.api
It then stores the stores the information in a SQLite database. App makes use of web services and async calls.
Next version of MusicMe uses information stored about artists in the database to pull all album information from discogs.com for each of the artists, and stores it in the database. Queries are run against the database to show the user new music that they do not have from artists they do have. Links to albums/songs for playing will also be shown, with possibly album art.