Are headphones plugged in? iOS7

Just to extend @Antonio's answer. If you need to detect whether the user has pulled out or plugged in the headphone.

#import <AVFoundation/AVFoundation.h>

---

// [AVAudioSession sharedInstance]; // @Boris edited: you may need it if there is no `AVAudioSession instance` created before. If doesn't work, uncomment this line.
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(audioRouteChangeListenerCallback:)
                                             name:AVAudioSessionRouteChangeNotification
                                           object:nil];
// don't forget to `removeObserver:`

---

// If the user pulls out he headphone jack, stop playing.
- (void)audioRouteChangeListenerCallback:(NSNotification*)notification
{
    NSDictionary *interuptionDict = notification.userInfo;

    NSInteger routeChangeReason = [[interuptionDict valueForKey:AVAudioSessionRouteChangeReasonKey] integerValue];

    switch (routeChangeReason) {

        case AVAudioSessionRouteChangeReasonNewDeviceAvailable:
            NSLog(@"AVAudioSessionRouteChangeReasonNewDeviceAvailable");
            NSLog(@"Headphone/Line plugged in");
            break;

        case AVAudioSessionRouteChangeReasonOldDeviceUnavailable:
            NSLog(@"AVAudioSessionRouteChangeReasonOldDeviceUnavailable");
            NSLog(@"Headphone/Line was pulled. Stopping player....");
            break;

        case AVAudioSessionRouteChangeReasonCategoryChange:
            // called at start - also when other audio wants to play
            NSLog(@"AVAudioSessionRouteChangeReasonCategoryChange");
            break;
    }
}

This should work, but I cannot test it right now, I'll do in the evening.

- (BOOL)isHeadsetPluggedIn {
    AVAudioSessionRouteDescription* route = [[AVAudioSession sharedInstance] currentRoute];
    for (AVAudioSessionPortDescription* desc in [route outputs]) {
        if ([[desc portType] isEqualToString:AVAudioSessionPortHeadphones])
            return YES;
    }
    return NO;
}