Face ID userFallback在iOS swift中不工作

我在iOS应用程序中安装了一个人脸识别码。当身份验证失败时，将显示包含“取消”和“重试”按钮的警报，“取消”按钮起作用，但“重试”按钮不起作用。如何编辑此按钮或“重试”按钮。当我单击“重试”按钮时，如果我单击“取消”按钮，则不会发生任何事情。该按钮正在工作，甚至“取消”按钮的标题也在更改，但没有对“重试”应用任何操作。我尝试了以下代码，并在internet上进行了大量搜索，但未找到任何内容。

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尝试此代码

是否可以将屏幕截图设置为警报？是的，请参阅更新的POST没有设备，但我在模拟器中测试。是的，你是对的，ios肯定有一些bug，但如果你再次扫描人脸，如果匹配，对话将自动关闭。是的，我认为这是ios端的bug

func startFaceIDTest(){
    attempted = true
    if context.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: &error) {
        let reason = "Identify yourself!"
        context.evaluatePolicy(LAPolicy.deviceOwnerAuthenticationWithBiometrics, localizedReason: reason, reply: { 
            successfaceID, authenticationError in

            DispatchQueue.main.async {
                if successfaceID {
                    self.success = true
                } else {
                    self.success = false

                    guard let errorr = authenticationError else {return}

                    switch(errorr) {
                        case LAError.authenticationFailed:
                            print("Failed")
                            break
                        case LAError.userCancel:
                            print("User cancel")
                            break
                        case LAError.userFallback:
                            print("Fallback")
                            break
                        case LAError.systemCancel:
                            print("System cancel")
                            break
                        default:
                            break
                    }
                }
            }
        })
    } else {
        if let err = error {
            if #available(iOS 11.0, *) {
                self.success = false
                switch err.code {
                    case LAError.Code.biometryNotEnrolled.rawValue:
                        notifyUser("Your device not enrolled for biometric",
                                   err: err.localizedDescription)

                    case LAError.Code.passcodeNotSet.rawValue:
                        notifyUser("A passcode has not been set",
                                   err: err.localizedDescription)

                    case LAError.Code.biometryNotAvailable.rawValue:
                        notifyUser("Biometric authentication not available",
                                   err: err.localizedDescription)

                    default:
                        notifyUser("Unknown error",
                                   err: err.localizedDescription)
                }
            } else {
                // Fallback on earlier versions
            }
        }
    }
}

func notifyUser(_ msg: String, err: String?) {
    let alert = UIAlertController(title: msg, message: err, preferredStyle: .alert)

    let cancelAction = UIAlertAction(title: "OK", style: .cancel, handler: nil)

    alert.addAction(cancelAction)

    self.present(alert, animated: true, completion: nil)
}

func bioandpasscodeAuthentication() {
    let context = LAContext()
    var error:NSError?

    // edit line - deviceOwnerAuthentication
    guard context.canEvaluatePolicy(.deviceOwnerAuthentication, error: &error) else {
        //showAlertViewIfNoBiometricSensorHasBeenDetected()
        return
    }

      let reason = "Identify yourself!"

    // edit line - deviceOwnerAuthentication
    if context.canEvaluatePolicy(.deviceOwnerAuthentication, error: &error) {

        // edit line - deviceOwnerAuthentication
        context.evaluatePolicy(.deviceOwnerAuthentication, localizedReason: reason, reply: { (success, error) in
            if success {
                DispatchQueue.main.async {
                    print("Authentication was successful")
                }
            }else {
                DispatchQueue.main.async {
                    //self.displayErrorMessage(error: error as! LAError )
                    print("Authentication was error")
                }
            }
        })
    }else {
        // self.showAlertWith(title: "Error", message: (errorPointer?.localizedDescription)!)
    }
}