我正在尝试从AVAudioSession.sharedInstance().availableInputs更改所有可用设备之间的音频输入（麦克风）。我使用AVAudioSession.routeChangeNotification来获取自动路由更改时，设备连接/断开，并更改首选输入与setPreferredInput，然后我重新启动我的audioEngine，它工作正常。
但当我尝试以编程方式更改首选输入时，它不会更改音频捕获inputNode。但保留最后连接的设备和捕获。
即使AVAudioSession.sharedInstance().currentRoute.inputs发生了变化，但audioEngine?.inputNode不会更改为setPreferredInput调用。
WhatsApp似乎没有任何问题。

任何建议或线索都非常感谢。谢谢
这是一些相关的代码段。enableMic编程是一个问题。

private var audioEngine: AVAudioEngine?
    private var inputNode: AVAudioNode!

    private func setupAudioSession() {
        do {
            let session = AVAudioSession.sharedInstance()
            try session.setCategory(.playAndRecord, options: [.defaultToSpeaker, .allowBluetooth])
            try session.setActive(true)
        } catch {
            print(error)
        }
    }

    func setupAudioEngine() {
        audioEngine?.stop()
        audioEngine?.reset()

        setupAudioSession()

        audioEngine = AVAudioEngine()
        inputNode = audioEngine?.inputNode

        guard let hardwareSampleRate = audioEngine?.inputNode.inputFormat(forBus: 0).sampleRate else { return }

        let format = AVAudioFormat(standardFormatWithSampleRate: hardwareSampleRate, channels: 1)

        let requiredBufferSize: AVAudioFrameCount = 4800

        inputNode.installTap(onBus: 0,
                             bufferSize: requiredBufferSize,
                             format: format
        ) { [self] (buffer: AVAudioPCMBuffer, _: AVAudioTime) in
            // process the buffer
        }

        audioEngine?.prepare()
    }

    func startRecording() {
        do {
            try audioEngine?.start()
        } catch {
            print("Could not start audioEngine: \(error)")
        }
    }

    private func observeRouteChanges() {
        NotificationCenter.default.addObserver(self,
                                               selector: #selector(handleRouteChange),
                                               name: AVAudioSession.routeChangeNotification,
                                               object: nil)
    }

    @objc func handleRouteChange(notification: Notification) {
        guard let userInfo = notification.userInfo,
              let reasonValue = userInfo[AVAudioSessionRouteChangeReasonKey] as? UInt,
              let reason = AVAudioSession.RouteChangeReason(rawValue: reasonValue) else {
            return
        }

        switch reason {

        case .newDeviceAvailable, .oldDeviceUnavailable:
            // enableMic with current route AVAudioSession.sharedInstance().currentRoute.inputs.first

        default: ()
        }

    }

    private func enableMic(mic: AVAudioSessionPortDescription?) {
        let session = AVAudioSession.sharedInstance()
        do {
            try session.setPreferredInput(mic)
            // re-setup the audio engine and start
        } catch {
            print(error)
        }
    }