这可以通过MediaPlayer模块完成：

(MPVolumeView().subviews.filter{ NSStringFromClass($0.classForCoder) == "MPVolumeSlider" }.first as? UISlider)?.setValue(0, animated: false)

请注意您可以更改的两个值：

value: how much volume you want (0 in this case)
animated: allowing you to animate the change visually

Swift 5 / Xcode 11
第一步：

import MediaPlayer

第二步：

let slider = MPVolumeView().subviews.first(where: { $0 is UISlider }) as? UISlider

第三步：

slider?.setValue(0.0, animated: false)

这对我很有效

//isMuted is a variable i use to check for the mute mode 
if isMuted == true {
        do {
            try AVAudioSession.sharedInstance().setCategory(.ambient, 
                mode: .default, options: .mixWithOthers)
            try AVAudioSession.sharedInstance().setActive(true)
        } catch {
            print(error)
        }
        
    }
    else {
        do {
            try AVAudioSession.sharedInstance().setCategory(.playback, mode: .default, options: .mixWithOthers)
            try AVAudioSession.sharedInstance().setActive(true)
        } catch {
            print(error)
        }
    }