Handling Audio Route Changes

handleRouteChange.swift

#import AVFoundation

// Observe the route change notification
NotificationCenter.default.addObserver(
    self,
    selector: #selector(handleRouteChange),
    name: AVAudioSession.routeChangeNotification,
    object: AVAudioSession.sharedInstance()
)

@objc private func handleRouteChange(_ notification: Notification) {
    // pull the reason the route changed out of the notification
    guard let info = notification.userInfo,
          let rawReason = info[AVAudioSessionRouteChangeReasonKey] as? UInt else { return }

    let reason = AVAudioSession.RouteChangeReason(rawValue: rawReason)

    // if the reason is that the old device is no longer available
    if reason == .oldDeviceUnavailable {
        let previousRoute = info[AVAudioSessionRouteChangePreviousRouteKey] as? AVAudioSessionRouteDescription
        let portType = previousRoute?.outputs.first?.portType
        
        // and that old device was headphones
        if portType == .headphones {
            // stop the audio that the user potentially wanted to keep private
            stopPlayingAudio()
        }
    }
}