How to change device Volume on iOS - not music volume

Question

I want to change the device volume on iOS (iphone).

I know that i can change the volume of music library with this lines below:

//implement at firs         


        

Answer 1

Call listenVolumeButton in your viewDidLoad and replace the // line with whatever you want to do.

private func listenVolumeButton() {
    let audioSession = AVAudioSession.sharedInstance()
    try? audioSession.setActive(true)
    audioSession.addObserver(self,
                             forKeyPath: "outputVolume",
                             options: NSKeyValueObservingOptions.new,
                             context: nil)

    hideVolumeView()
}

private func hideVolumeView() {
    let volumeView = MPVolumeView(frame: CGRect.zero)
    for subview in volumeView.subviews {
        if let button = subview as? UIButton {
            button.setImage(nil, for: .normal)
            button.isEnabled = false
            button.sizeToFit()
        }
    }
    UIApplication.shared.windows.first?.addSubview(volumeView)
    UIApplication.shared.windows.first?.sendSubviewToBack(volumeView)
}

override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey: Any]?, context: UnsafeMutableRawPointer?) {
    switch keyPath {
    case "outputVolume":
        guard let systemSlider = MPVolumeView().subviews.first(where: { NSStringFromClass($0.classForCoder) == "MPVolumeSlider" }) as? UISlider else {
            return
        }

        let avoidLimitsValue = max(min(AVAudioSession.sharedInstance().outputVolume, Float(0.9)), Float(0.1))

        DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 0.01) {
            systemSlider.setValue(avoidLimitsValue, animated: false)
        }

        // DO YOUR STUFF HERE
    default:
        break
    }
}