audioRouteChangeListenerCallback

gistfile1.m

void audioRouteChangeListenerCallback (
                                       void                      *inUserData,
                                       AudioSessionPropertyID    inPropertyID,
                                       UInt32                    inPropertyValueSize,
                                       const void                *inPropertyValue
                                       ) {  
  // ensure that this callback was invoked for a route change
  if (inPropertyID != kAudioSessionProperty_AudioRouteChange) return;

  if ([inUserData isKindOfClass:[IVAudioPlayerController class]]) {
    IVAudioPlayerController *controller = (IVAudioPlayerController *) inUserData;
    
    // if application sound is not playing, there's nothing to do, so return.
    if (controller.audioStreamer.state == AS_STOPPED ) {
      TTDPRINT(@"Audio route change while application audio is stopped.");
      return;
    } else {
      
      // Determines the reason for the route change, to ensure that it is not
      //		because of a category change.
      CFDictionaryRef	routeChangeDictionary = inPropertyValue;
      
      CFNumberRef routeChangeReasonRef =
      CFDictionaryGetValue ( routeChangeDictionary, CFSTR (kAudioSession_AudioRouteChangeKey_Reason) );
      
      SInt32 routeChangeReason;
      
      CFNumberGetValue ( routeChangeReasonRef, kCFNumberSInt32Type, &routeChangeReason );
      
      // "Old device unavailable" indicates that a headset was unplugged, or that the
      //	device was removed from a dock connector that supports audio output. This is
      //	the recommended test for when to pause audio.
      if (routeChangeReason == kAudioSessionRouteChangeReason_OldDeviceUnavailable) {
        TTDPRINT(@"Output device removed, so application audio was paused.");
        [controller pause];
      } else {
        TTDPRINT(@"A route change occurred that does not require pausing of application audio.");
      }
    }
  }
  
}

thanks! found it useful