Face ID userFallback not working in iOS swift - ios

Question

I a implementing face ID in my iOS app. When authentication fails a alert shows containing cancel and try again buttons, cancel button works but try again button not working. How can I edit this button or to be worked try again button. When i Click on try again button nothing happens if i click on cancel button that is working and even title of cancel button also be changing but no action is applying on try again.I have tried the following code and had a lot of search on internet but nothing found.
enter image description here
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)
}

Answer 1

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)!)
}
}
try this code