So I wanted to integrate the spotify library into an android app. I went to https://developer.spotify.com/technologies/libspotify/ and downloaded their lib libspotify-12.1.5
Spotify have announced that they released the Android SDK(https://developer.spotify.com/technologies/spotify-android-sdk/).
And the tutorial is here(https://developer.spotify.com/technologies/spotify-android-sdk/tutorial/), so you can easily integrate Spotify into your Android application.