Question

I am writing an audio application which plays media items from the iPod music library using the iPod music player.

Now I know it is possible for the iPod to carry on playing when it is in the background, but I want to also run either a Thread or a Timer in the background where a selector method periodically checks the state of the music player so that the app can apply rules in order to apply delays between tracks, and automatically load up new media collections into the player all while in the background.

Is this possible?

If not, is there any other method for achieving this functionality?

Answer 1

The trick is to not use MPMusicPlayerController as when your app enters the background it actually relinquishes control to the iPod app (you can check this by closing your app and opening the iPod app).

For the music app I’m currently developing I’ve rolled my own music player using AVAudioSession and AVPlayer (not AVAudioPlayer). I’ve implemented a queue on the player, and a datasource (similar to UITableViewDatasource) which feeds the queue. All of this works eloquently whilst running in the background and has no association what ever with the iPod app (and as an added bonus you apps icon appears next to the remote controls on mulitasking bar).

If you developed something similar then when you ask your datasource for the next item in the queue, you could query your rule set and take a decision on what to do next.