Using iPodMusicPlayer without giving control to iPod in background

I'm developing an app with a very specific focus on shuffling songs within a selected playlist. When the app launches, it lists all the user's playlists, and then when one is selected it loads it into my music player view and get's going. I'm using an MPMusicPlayerController iPodMusicPlayer to handle doing this because I'm pretty new at iOS development and it handles backgrounding and everything nice and easily for me. I want music to continue playing in the background and I like how whatever I change within my app is also reflected in the iPod app. However, I don't want the user to be able to change things in the iPod app and then return to mine. Since my app is all about shuffling, the user could easily go into iPod and disable shuffle, then come back to my app and the experience is ruined. I also don't want them to change the play开发者_如何学JAVAlist from within iPod.

Can anyone help me think of a way to accomplish this? Play/pause/skip/prev/volume is no problem from within iPod (I want that to be possible), but I don't want changing the song queue to be possible. Is there a way I could add a handler in my app that catches if the user changed something while my app was in the background (and if so, stop music and reset my app to the initial screen)? I'd really appreciate any suggestions. I'm hoping something like this is possible before I venture into using AVPlayerQueue or the like (as a side note, can you play DRM'd files with AVPlayerQueue?).

---

What I would do is set a bool when backgrounded:

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
[prefs setBool:YES forKey:@"BACKGROUNDED"];

Then, in your handler for the MPMusicPlayerControllerNowPlayingItemDidChangeNotification that you should be implementing so that you have that control, do the following:

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
if ([prefs boolForKey:@"BACKGROUNDED"]) {
    [prefs setBool:NO forKey:@"BACKGROUNDED"];
    exit(0);
}

It might be too abrupt, depending on when it checks this code (I don't know when it does in your project) but that should accomplish your goal. exit(0) is the way to terminate your app without throwing an exception. Is that helpful?