How to enable iPod controls in the background to control non-iPod music in iOS 4?

Question

A good example of what I'm trying to accomplish is implemented in the latest version of the Spotify iPhone application for (Pandora seems to have the same feature) .

When Spotify is in the background, double tapping opens the "multi-task dock", where the ipod controls (play/pause, forward etc) allow to control the music playback of Spotify (not the ipod application). Also, when the iphone/ipod touch is locked, double tapping displays similar playback controls.

If you don't know what I mean, here's an article that has screenshots : http://www.wired.com/gadgetlab/2010/07/spotify-updated-for-ios4-ready-to-replace-ipod/

In my current application, music is streamed from a server (using Matt Gallagher's AudioStreamer). I've managed to keep the music playing in the background. Now, I'd like to link my playback to the "multi-task dock"/lock screen.

Should I be using [MPMusicPlayerController iPodMusicPlayer] ? How should I proceed ?

Bonus question : if you can tell me how to change the ipod icon to my application icon in the "multi-task dock" (Spotify pulled that trick as well...), that whould be AWESOME.

Any help appreciated, thanks.

Answer 1

Problem is solved.

In short, to enable remote control event, 1) use :

- (void)remoteControlReceivedWithEvent:(UIEvent *)theEvent

and 2) put this is your view controller :

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
    [self becomeFirstResponder];
}
- (BOOL)canBecomeFirstResponder {
    return YES;
}

I have to give credit to Grant. He has forked Matt Gallagher's AudioStreamer enabling all the ios4 improvements (background audio, and remote controls working). You can find his sources along with a working sample on github : http://github.com/DigitalDJ/AudioStreamer

Regarding the icon : once you use beginReceivingRemoteControlEvents, the icon automatically switches to your app icon. Brilliant !