Headphones plugin/out detection in Swift - iphone

Question

im working on an iphone app for iOS 8.1 that works with core audio to generate frequencies and adjust intensities. In the view controller that i generate the frequencies i need to control if the headphones are plugged out in some moment, i'm already controlling if headphones are connected before proceed to my frequencies generator view with the following function:
- (BOOL)isHeadsetPluggedIn {
AVAudioSessionRouteDescription* route = [[AVAudioSession sharedInstance] currentRoute];
for (AVAudioSessionPortDescription* desc in [route outputs]) {
if ([[desc portType] isEqualToString:AVAudioSessionPortHeadphones])
return YES;
}
return NO;
}
this function is in C because im working with core-audio to generate the frequencies, but in the view controllers im working with swift so a need a way to implement a listener to detect the headphones plug-out event and return to the user to the previous view, i don't know if i can use my function isHeadsetPluggedin() with an event listener or i should make a new one.
In my MenuViewController i control if the headphones are plugged in using the following function:
func isHeadsetPluggedIn() -> Bool {
return freqController.isHeadsetPluggedIn();
}

Answer 1

In Swift 4
func activateHeadPhonesStatus(){
NotificationCenter.default.addObserver(self, selector: #selector(audioRouteChangeListener(_:)), name: AVAudioSession.routeChangeNotification, object: nil)
}
#objc func audioRouteChangeListener(_ notification:Notification) {
guard let userInfo = notification.userInfo,
let reasonValue = userInfo[AVAudioSessionRouteChangeReasonKey] as? UInt,
let reason = AVAudioSession.RouteChangeReason(rawValue:reasonValue) else {
return
}
switch reason {
case .newDeviceAvailable:
let session = AVAudioSession.sharedInstance()
for output in session.currentRoute.outputs where output.portType == AVAudioSession.Port.headphones {
headphonesConnected = true
print("headphone plugged in")
break
}
case .oldDeviceUnavailable:
if let previousRoute =
userInfo[AVAudioSessionRouteChangePreviousRouteKey] as? AVAudioSessionRouteDescription {
for output in previousRoute.outputs where output.portType == AVAudioSession.Port.headphones {
headphonesConnected = false
print("headphone pulled out")
break
}
}
default: ()
}
}

Answer 2

You can track the route changes by observing AVAudioSessionRouteChangeNotification notification.
//Observe for route changing notification
[[NSNotificationCenter defaultCenter]addObserver:self selector:#selector(handleRouteChange:) name:AVAudioSessionRouteChangeNotification object:[AVAudioSession sharedInstance]];
-(void)handleRouteChange:(NSNotification *)notif
{
NSDictionary *dict = notif.userInfo;
AVAudioSessionRouteDescription *routeDesc = dict[AVAudioSessionRouteChangePreviousRouteKey];
AVAudioSessionPortDescription *prevPort = [routeDesc.outputs objectAtIndex:0];
if ([prevPort.portType isEqualToString:AVAudioSessionPortHeadphones]) {
//Head phone removed
}
}

Answer 3

This article worked for me. There is also a GitHub repo with solution. If you don't want to read, here is my code:
Put this in your INIT method:
self.session = AVAudioSession.sharedInstance()
let currentRoute = self.session.currentRoute
if currentRoute.outputs.count != 0 {
for description in currentRoute.outputs {
if description.portType == AVAudioSessionPortHeadphones {
print("headphone plugged in")
} else {
print("headphone pulled out")
}
}
} else {
print("requires connection to device")
}
NSNotificationCenter.defaultCenter().addObserver(
self,
selector: #selector(YOUR_VIEW_CONTROLLER_OR_VIEW.audioRouteChangeListener(_:)),
name: AVAudioSessionRouteChangeNotification,
object: nil)
And put this anywhere in your class:
dynamic private func audioRouteChangeListener(notification:NSNotification) {
let audioRouteChangeReason = notification.userInfo![AVAudioSessionRouteChangeReasonKey] as! UInt
switch audioRouteChangeReason {
case AVAudioSessionRouteChangeReason.NewDeviceAvailable.rawValue:
print("headphone plugged in")
case AVAudioSessionRouteChangeReason.OldDeviceUnavailable.rawValue:
print("headphone pulled out")
default:
break
}
}
Take care!