DrCachetes DrCachetes - 5 months ago 19
Swift Question

how to use an event listener to detect headset plug out in swift?

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

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
          }
     }
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