Controlling volume of Apple Watch

Question

I'm trying to control the volume of the Apple Watch itself in code from SwiftUI.

I'm streaming audio using the AVPlayer.

Is there an API to set the Volume of the Watch or use to Digital Crown to control the volume without

• Setting the volume property on the AVPlayer. This just set the volume relative to the system volume. So if the system is muted it does not increase the volume.
• Using the WKInterfaceVolumeControl. This does the job, but it can not be sized does and takes a lot of space on the small screen.

Answer 1

The workaround I ended up with was this:

1. Wrap the WKInterfaceVolumeControl to use it in SwiftUI

struct VolumeView: WKInterfaceObjectRepresentable {
    typealias WKInterfaceObjectType = WKInterfaceVolumeControl


    func makeWKInterfaceObject(context: Self.Context) -> WKInterfaceVolumeControl {
        let view = WKInterfaceVolumeControl(origin: .local)
        Timer.scheduledTimer(withTimeInterval: 1, repeats: true) { [weak view] timer in
            if let view = view {
                view.focus()
            } else {
                timer.invalidate()
            }
        }
        DispatchQueue.main.async {
            view.focus()
        }
        return view
    }
    func updateWKInterfaceObject(_ wkInterfaceObject: WKInterfaceVolumeControl, context: WKInterfaceObjectRepresentableContext<VolumeView>) {
    }
}

2. Add the VolumeView to the view hierarchy with opacity = 0.

        .background(VolumeView().opacity(0))

3. Listen to volume updates from the system.

volumeObserver = AVAudioSession.sharedInstance().observe(\.outputVolume) { session, _ in
            print("Output volume: \(session.outputVolume)")
            self.volume = Double(session.outputVolume)
        }

With that you can update some other view, but keep in mind that especially on older what's the update does not always happen (immediately).

Answer 2

leoMehlig's answer only works for me if I add a bit of delay and resign the focus before focusing for the first time.

So, speaking in code, I changed this:

DispatchQueue.main.async {
    view.focus()
}

to this:

DispatchQueue.main.asyncAfter(deadline: .now() + 0.3) {
    view.resignFocus()
    view.focus()
}

Answer 3

leoMehlig's answer works for me as is, but I noticed the embedded WKInterfaceVolumeControl was losing focus when I would tap anywhere on the watch screen.

This was because I had a .focusable(true) modifier in the view hierarchy, so any view being tapped further up in the hierarchy would keep the focus.

I had added the .focusable(true) when I was trying to bind AVPlayer.volume to the digital crown rotation, it was no longer needed when using WKInterfaceVolumeControl