Styjun

Is it possible to detect that the user has an external headset plugged into the iPhone's 3.5mm connector or the 30-pin connector? I want to output audio only to an external audio device, and keep silent if nothing is connected.

The answer is very similar to the answer to this question, but you'll want to get the kAudioSessionProperty_AudioRoute property instead.

Call this method to find out the bluetooth headset is connected or not.

First import this framework #import <AVFoundation/AVFoundation.h>

- (BOOL) isBluetoothHeadsetConnected
 
 AVAudioSession *session = [AVAudioSession sharedInstance];
 AVAudioSessionRouteDescription *routeDescription = [session currentRoute];

 NSLog(@"Current Routes : %@", routeDescription);

 if (routeDescription)
 
 NSArray *outputs = [routeDescription outputs];

 if (outputs && [outputs count] > 0)
 
 AVAudioSessionPortDescription *portDescription = [outputs objectAtIndex:0];
 NSString *portType = [portDescription portType];

 NSLog(@"dataSourceName : %@", portType);

 if (portType && [portType isEqualToString:@"BluetoothA2DPOutput"])
 
 return YES;
 
 
 

 return NO;
 

There is nice article about this in Apple documentation:
https://developer.apple.com/documentation/avfoundation/avaudiosession/responding_to_audio_session_route_changes

Only you have to verify if portType == AVAudioSessionPortBluetoothA2DP

func setupNotifications() 
 let notificationCenter = NotificationCenter.default
 notificationCenter.addObserver(self,
 selector: #selector(handleRouteChange),
 name: .AVAudioSessionRouteChange,
 object: nil)



@objc func handleRouteChange(notification: Notification) 
 guard let userInfo = notification.userInfo,
 let reasonValue = userInfo[AVAudioSessionRouteChangeReasonKey] as? UInt,
 let reason = AVAudioSessionRouteChangeReason(rawValue:reasonValue) else 
 return
 
 switch reason 
 case .newDeviceAvailable:
 let session = AVAudioSession.sharedInstance()
 for output in session.currentRoute.outputs where output.portType == AVAudioSessionPortBluetoothA2DP 
 headsetConnected = true
 break
 
 case .oldDeviceUnavailable:
 if let previousRoute =
 userInfo[AVAudioSessionRouteChangePreviousRouteKey] as? AVAudioSessionRouteDescription 
 for output in previousRoute.outputs where output.portType == AVAudioSessionPortBluetoothA2DP 
 headsetConnected = false
 break
 
 
 default: ()
 


func isBluetoothHeadsetConnected() -> Bool 
 var result = false
 let session = AVAudioSession.sharedInstance()
 for output in session.currentRoute.outputs where output.portType == AVAudioSessionPortBluetoothA2DP 
 result = true
 
 return result