iOS

This article describes how to trigger when headphones are plugged/ unplugged.

These steps should be implemented on the application side.

NSNotificationCenter *nc [NSNotificationCenter defaultCenter];
[nc addObserver:self
       selector:@selector(routeChanged:)
           name:AVAudioSessionRouteChangeNotification
         object:nil];         

This code was taken from:
Responding to Audio Hardware Route Changes.

Use the KPController instance under ‘KPViewController’ to control your playback.