How can I integrate a music app in the iOS system that my own custom player can handle actions (play, pause, forward) from the unlock screen and how to integrate that is displayed as player app in the double-click-home-button menu like on this screenshot Spotify does:
EDIT: The application itself is based at the Media Player Framework, but in this documents there isn’t any hint how to get the custom player in this ‘double-click-home-button’ menu.
If you register your application for remote control events, and if you start playing either audio or video, your application will automatically take over these controls. See Apple’s documentation for more info. This API is available on iOS 4 and later.
To set the string below the controls (“The Butterfly Defect” in your screenshot), use
MPNowPlayingInfoCenter, available on iOS 5 and later.