detect up volume change swift

Question

I\'m having problems detecting when someone presses up or down volume button. For the moment I just play a file but I want to know when the user presses the button to show a

Answer 1

This should do the trick.

class ViewController: UIViewController {

    // MARK: Properties

    let notificationCenter = NSNotificationCenter.defaultCenter()

    // MARK: Lifecycle

    override func viewDidAppear(animated: Bool) {

        super.viewDidAppear(animated)

        notificationCenter.addObserver(self,
            selector: #selector(systemVolumeDidChange),
            name: "AVSystemController_SystemVolumeDidChangeNotification",
            object: nil
        )
    }

    override func viewDidDisappear(animated: Bool) {

        super.viewDidDisappear(animated)

        notificationCenter.removeObserver(self)
    }

    // MARK: AVSystemPlayer - Notifications

    func systemVolumeDidChange(notification: NSNotification) {

        print(notification.userInfo?["AVSystemController_AudioVolumeNotificationParameter"] as? Float)
    }
}