Add image on lock screen in iOS app, when app is running in background

Question

There are many question on site like

Programatically changing the iOS lock-screen ,

How to set lock screen , wallpaper and Ringtone programmatically in iPhone? All say that apple will reject if we modify the lock-Screen image.

But I seen it in many apps. Example Saavn is in AppStore.

In this if a song is playing and device is locked, It shows the image of the current album on the lock screen.

Please share if anybody know how it can be done. Thanks.

Answer 1

Music apps can change the lock screen wallpaper because iOS automatically displays the album artwork for the song/podcast/etc that's playing (see MPMusicPlayerController docs). As far as I know, it's not an API that's publicly available to developers.