These classes follow the standard Cocoa delegate pattern.
First, set yourself as the delegate on your track player:
self.trackPlayer.delegate = self;
Then implement the delegate method in whatever self
is:
-(void)trackPlayer:(SPTTrackPlayer *)player didEndPlaybackOfTrackAtIndex:(NSInteger)index ofProvider:(id<SPTTrackProvider>)provider {
// Track playback ended.
}
Your delegate method will then be called by the track player when appropriate.