In my application, I attempt to login with Face ID using evaluatePolicy, and after 1 or 2 logins, I get an error in the callback. In that error, I call an async completion handler which calls another and eventually it calls canEvaluatePolicy. My app then freezes, allowing no further interaction with the UI. Why would this be happening? Does it have something to do with thread-safety? Some sample code that recreates this issue, can be found here
Here is a code snippet from that sample code for reference:
let localAuthenticationContext = LAContext()
if localAuthenticationContext.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: nil) {
localAuthenticationContext.evaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, localizedReason: "To access secure data") { success, evaluateError in
if success {
print("Success")
} else {
print("Face ID Error")
let context = LAContext()
let status = context.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: nil)
print("Status: \(status)")
}
}
}
I've been using Xcode 9.1 Beta 2 with the iPhone X simulator.
Related
Sometimes the CallKit UI is not visible.
This happens all the time when the user clicks on the "Remind me" button on CallKit UI and cancel the call.
Now, when the user gets the call for the second time, there is only vibration but no UI for CallKit.
let callHandle = CXHandle(type: .generic, value: callerName ?? "Unknown".localized)
let callUpdate = getCallUpdate(callHandle: callHandle)
print("reportNewIncomingCall uuid = \(uuid)")
callKitProvider.reportNewIncomingCall(with: uuid, update: callUpdate) { error in
if let error = error {
NSLog("Failed to report incoming call successfully: \(error.localizedDescription).")
} else {
NSLog("Incoming call successfully reported.")
}
completion?(error as NSError?)
}
I am also faced this issue and came to know that I have used same uuid for all calls, after changing it to below it worked for me .so make sure to generate new uuid for each call.
provider.reportNewIncomingCall(with: UUID(), update: update) { error in
if let error = error{
print("error while reporting incoming call \(error)")
}else{
print("incoming call successfully reported")
}
completion?(error)
}
I've implemented password/TouchID/FaceID on a view controller and when I hit the success case, I'd expect the prompt to stop firing but it just fires over and over again.
In my VC:
var context: LAContext!
func authenticateReturningUser() {
context = LAContext()
var error: NSError?
if context.canEvaluatePolicy(.deviceOwnerAuthentication, error: &error) {
let reason = "Verify that this is your device to continue."
context.evaluatePolicy(.deviceOwnerAuthentication, localizedReason: reason) { success, error in
DispatchQueue.main.sync {
guard success else {
guard let error = error else {
// show error
return
}
switch error {
case LAError.userCancel:
// do stuff
return
default: return
}
}
print("success")
}
}
}
}
The prompt should fire once and not again if the user successfully authorizes
Edit:
authenticateReturningUser is called from the AppDelegate's applicationDidBecomeActive function:
self.coverVC?.completionHandler = { self.removeBackgroundVC() }
self.coverVC?.authenticateReturningUser()
As far as I remember, when showing the Touch ID prompt, your app becomes inactive. So when the prompt is dismissed, your app becomes active again, triggering the App Delegate's applicationDidBecomeActive again.
You might consider introducing a flag that stores whether the app became inactive because of Touch ID / Face ID etc. or because of another reason and use it in applicationDidBecomeActive to decide if authentication should be triggered or not.
Where are you calling authenticateReturningUser()? You may want to create a static boolean authenticated that if false, allows the call to authenticateReturningUser(), and if true, skips the call, and set authenticated = true after calling the function once.
I want to use TouchID in my app and I've found some weird behaviour. So in general when TouchID alert is shown it and user try to authenticate with fingerprint canEvaluatePolicy will fail only after 3 attempts but if user go to Settings>Touch ID & Passcode and turn off "use touch id for: iPhone Unlock" canEvaluatePolicy will fail after first attempt with error message "Biometry is disabled for unlock.". Does anyone know is it a bug or it is by design.
Also looks like it happens only on iOS 11.
Here is code that i use for TouchID configuration
var error: NSError?
context.localizedFallbackTitle = "fallback title"
if context.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: &error) {
context.evaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, localizedReason: reason) { success, authenticationError in
DispatchQueue.main.async {
if success {
// success case
}
else {
// error handling
}
}
}
}
else {
// error handling
}
Actually, I building an app which contains local authentication.
My code so far:
func authenticateUser() {
let authenticationContext = LAContext()
var error: NSError?
let reasonString = "Touch the Touch ID sensor to unlock."
// Check if the device can evaluate the policy.
if authenticationContext.canEvaluatePolicy(LAPolicy.deviceOwnerAuthenticationWithBiometrics, error: &error) {
authenticationContext.evaluatePolicy( .deviceOwnerAuthenticationWithBiometrics, localizedReason: reasonString, reply: { (success, evalPolicyError) in
if success {
print("success")
} else {
if let evaluateError = error as NSError? {
// enter password using system UI
}
}
})
} else {
print("toch id not available")
// enter password using system UI
}
}
My problem is I want to use the passcode lock scene when the app doesn't has touch ID or invalid finger print.
Like below Image:
How can I do it?
You should use .deviceOwnerAuthentication instead of .deviceOwnerAuthenticationWithBiometrics to evaluate policy. With this parameter the system uses biometric authentication if available else it presents passcode screen. And if the biometric authentication is available but fails, a fallback button redirect to the passcode screen. See documentation :
If Touch ID or Face ID is available, enrolled, and not disabled, the user is asked for that first. Otherwise, they are asked to enter the device passcode.
Tapping the fallback button switches the authentication method to ask the user for the device passcode.
So your code will be:
func authenticateUser() {
let authenticationContext = LAContext()
var error: NSError?
let reasonString = "Touch the Touch ID sensor to unlock."
// Check if the device can evaluate the policy.
if authenticationContext.canEvaluatePolicy(LAPolicy.deviceOwnerAuthentication, error: &error) {
authenticationContext.evaluatePolicy( .deviceOwnerAuthentication, localizedReason: reasonString, reply: { (success, evalPolicyError) in
if success {
print("success")
} else {
// Handle evaluation failure or cancel
}
})
} else {
print("passcode not set")
}
}
At this point, I am afraid that you cannot access this passcode lock screen into your app, it is related to the iOS itself. You might need to build your own custom view controller to look/behave as the passcode lock scene (with Touch ID). I would suggest to use a library for achieving this, personally, I've tried PasscodeLock and it works fine for me.
For my app I need to save one page of it with TouchID. So the user is kinda forced to use TouchID or if the device does not support it, a password. If the user cancels the TouchID authentication, I want to View to disappear and get back to the root view. I already had that working, but somehow it does not work anymore and I really don't know why?! I just copied until the canceled option, the rest is does not matter I guess.
func authenticateUser() {
let context = LAContext()
var error: NSError?
let reasonString = "Authentication is needed to access your App"
if context.canEvaluatePolicy(LAPolicy.DeviceOwnerAuthenticationWithBiometrics, error: &error){
context.evaluatePolicy(LAPolicy.DeviceOwnerAuthenticationWithBiometrics, localizedReason: reasonString, reply: { (success, policyError) -> Void in
if success {
print("authentification successful")
}
}else{
switch policyError!.code{
case LAError.SystemCancel.rawValue:
print("Authentification was canceled by the system")
case LAError.UserCancel.rawValue:
print("Authentication was canceled by user")
self.navigationController?.dismissViewControllerAnimated(true, completion: nil)
//Yes I also tried popToRootViewController, still doesn't work
}
The documentation for the evaluatePolicy call says:
"Reply block that is executed when policy evaluation finishes. This block is evaluated on a private queue internal to the framework in an unspecified threading context."
So the problem is that you are trying to call navigation from the wrong thread. You need to make that call on the UI thread. For example:
dispatch_async(dispatch_get_main_queue()) {
// Navigation goes here
}