Authentication failed and Try Face Id Again does nothing

Question

I'm just follow this tutorial to authenticate user by Face ID but actually it's not work with "Try Face Id Again" button after authentication failed, the callback was not called and I don't know why. Here is the code:

@IBAction func touchIdAction(_ sender: UIButton) {

    print("hello there!.. You have clicked the touch ID")

    let myContext = LAContext()
    let myLocalizedReasonString = "Biometric Authntication testing !! "

    var authError: NSError?
    if #available(iOS 8.0, macOS 10.12.1, *) {
        if myContext.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: &authError) {
            myContext.evaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, localizedReason: myLocalizedReasonString) { success, evaluateError in

                DispatchQueue.main.async {
                    if success {
                        // User authenticated successfully, take appropriate action
                        self.successLabel.text = "Awesome!!... User authenticated successfully"
                    } else {
                        // User did not authenticate successfully, look at error and take appropriate action
                        self.successLabel.text = "Sorry!!... User did not authenticate successfully"
                    }
                }
            }
        } else {
            // Could not evaluate policy; look at authError and present an appropriate message to user
            successLabel.text = "Sorry!!.. Could not evaluate policy."
        }
    } else {
        // Fallback on earlier versions

        successLabel.text = "Ooops!!.. This feature is not supported."
    }


}

Running with Xcode 9.4.1 on iPhone X Simulator. Thanks

Teddie

Answer 1

Before tapping Try Face Id Again button you have to inform the simulator if it should simulate matching or non-matching face.

You can do it by selecting Hardware->Face ID->Matching Face/Non-matching Face

Gamine

@Teddie Ok. I've just updated the answer. It should resolve your issue. – Gamine

okay, just tried but it weir, I've selected Non-matching face before tap "Try FaceID Again" but nothing happen. Select "Non-matching" after tap works, and there's another popup with "Try Again" button appear, and this "Try Again" works as expected. Don't know if it's the issue with simulator because I don't have real device here. – Teddie

It's a simulator issue. Your code should work fine on real device. – Gamine

It doesn't work on my iPhoneX. I can't fall in LAError.authenticationFailed situation with real device at all. – Artema

This doesn't work in Xcode 12.0.1 with a simulator device running iOS 14. – Antithesis

Still doesn't work in Xcode 12.5 with a iPad OS 14.5 simulator. – Reshape

Answer 2

ANSWER: I had the same problem. Then I checked in device and it works. So this doesn't work only in simulator

Wizard