Ndtyjky

In my app I need to change volume with slider, I've got current volume with

@IBOutlet weak var volumeChange: UISlider! {

    didSet {

        let audioSession = AVAudioSession.sharedInstance()

        let volume : Float = audioSession.outputVolume

        volumeChange.setValue(volume, animated: true)

    }

}

How can I change it? Now I have this method

@IBAction func handleVolumeChange(_ sender: UISlider) {

    player.volume = sender.value

}

This method doesn't work in this case. Is it possible to make it like for example in Music app: changing volume in app with changing volume on device?

To get the volume then you will need to use AVAudioSession.sharedInstance().outputVolume as you already have used.

In order to allow the user to control the volume you will want to have a look at MPVolumeView found in the Media Player framework. This component is able to make changes to the system volume.

It is very simple to use:

let volumeView = MPVolumeView(frame: volumeViewSize)

playerView.addSubview(volumeView)

You will want to use this class instead of using your UISlider instance. There are methods supplied that let you override the look and feel of the slider.

Additionally this class exposes a control which allows the user to choose the output route (iPhone, Airpods, Homepod, or Apple TV for example). You can choose to disable either the slider or the output route control so this gives you a fairly broad set of options with customising your user interface.

If you are working with a storyboard then you will need to add it in code. First create an empty UIView in the view controller's view on the storyboard and attach that to your view controller:

Once you've added that you will want something like the following in your view controller:

@IBOutlet var volumeSliderContainer: UIView!



private lazy var volumeView: MPVolumeView = {

    let volumeView = MPVolumeView(frame: volumeSliderContainer.bounds)

    volumeView.showsVolumeSlider = true

    volumeView.showsRouteButton = true

    volumeView.translatesAutoresizingMaskIntoConstraints = false

    return volumeView

}()



override func viewDidLoad() {

    super.viewDidLoad()



    volumeSliderContainer.addSubview(volumeView)

    NSLayoutConstraint.activate([

        volumeView.widthAnchor.constraint(equalTo: volumeSliderContainer.widthAnchor),

        volumeView.heightAnchor.constraint(equalTo: volumeSliderContainer.heightAnchor),

        volumeView.centerXAnchor.constraint(equalTo: volumeSliderContainer.centerXAnchor),

        volumeView.centerYAnchor.constraint(equalTo: volumeSliderContainer.centerYAnchor),

    ])

}

Now you will be able to interact with the MPVolumeView as you require.

Just watch out on the simulator, the component will not render the slider and you will only be able to see it when running your app on an actual device.

get current system volume -

var session = AVAudioSession.sharedInstance()



override func viewDidLoad() {

    super.viewDidLoad()



    if ((try? session.setActive(true)) != nil) {

        volumeChange.setValue(session.outputVolume, animated: true)

    }

}