Hi,
I'm facing the same issue. It used to happen rarely also in early versions of iOS12. Now this issue is back. On my iPad Pro (A1674) with iPadOS13.1.2 it happens in almost every app I use or develop.
EDIT: I've just simulated this issue with the "Single View App" template in Xcode11. I added just one button pointing at this IBAction:
@IBAction func biometricAuth() {
DispatchQueue.main.async {
let context = LAContext()
var error: NSError?
print("Checking if can evaluate policy ...")
if (context.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: &error)) {
print("Evaluating policy ...")
context.evaluatePolicy(.deviceOwnerAuthenticationWithBiometrics,
localizedReason: "Testing biometrics") { (success, error) in
print("Biometrics success: \(success ? "YES" : "NO"). Error: \(error?.localizedDescription ?? "(null)")")
}
} else {
print("Cannot evaluate policy. Error: \(error?.localizedDescription ?? "(null)")")
}
}
}
The application prints "Evaluating policy ...", but the TouchID alert doesn't appear. It seems to be there, just not visible. It appears if I rotate the device or touch the figerprint reader.
Strange is that it seems to be "learning" to be broken. The app worked normally for a while and stopped showing the TouchID alert after few hours of testing.
Best regards,
Petr Hoffman