Customize keychain alert actions - ios

Question

I'm wondering if customization of the keychain alert is possible? Below you can find the image:
What I'm trying to achieve:
When the authentication with FaceID/TouchID fails and pops above shown alert, I want user to tap Enter Passcode and show my custom Application Passcode UI, instead of device passcode (system ui). Basically, I want to customize the fallback action.
Context:
I know it is possible with using LAContext, however due to the reasons that we can bypass it, I don't feel comfortable in implementing that, so I chose Keychain accessControlFlags.
Snapshot code, what I currently have:
func data(forAccount account: String, service: String, accessGroup: String?) throws -> Data? {
guard let accessControl = createAccessControl(with: .userPresence) else { return nil }
var query = self.query(forAccount: account, service: service, accessGroup: accessGroup)
var authContext = LAContext()
authContext.localizedFallbackTitle = "Enter Passcode"
authContext.localizedCancelTitle = "Cancel"
query[KeychainConstants.matchLimit] = KeychainConstants.matchLimitOne
query[KeychainConstants.returnData] = kCFBooleanTrue
query[KeychainConstants.authenticationContext] = authContext
query[KeychainConstants.accessControl] = accessControl
var result: AnyObject?
let status = withUnsafeMutablePointer(to: &result) {
securityItemManager.copyMatching(query, result: UnsafeMutablePointer($0))
}
if let error = error(fromStatus: status), error != .itemNotFound {
throw error
}
guard result != nil else { return nil }
guard let resultData = result as? Data else { throw AccessError.invalidQueryResult }
return resultData
}

Answer 1

The only customization you can do is change the dialog buttons labels. You can do this using the following:
let context = LAContext()
context.localizedFallbackTitle = ""
context.localizedCancelTitle = "Manual connection"
By setting the localizedFallbackTitle property to an empty string removes the fallback button (enter password).
Unfortunately, there is no "delegate" kind of callback for this dialog. You need to manage the user interaction using errors. Therefore, LAError.userCancel is triggered when user has pressed the cancel button and LAError.userFallback is triggered when the fallback button has been pressed.
Here's an example:
let context = LAContext()
context.localizedFallbackTitle = "Facebook"
context.localizedCancelTitle = "Web Connection"
[...]
context.evaluatePolicy(.deviceOwnerAuthenticationWithBiometrics,
localizedReason: "My reason") { (success, errorOrNil) in
if let error = errorOrNil {
if success {
// The evaluation succeeded
} else {
if let error = errorOrNil {
switch error {
case .userCancel:
// Execute the custom actions you want to do. Here it would be
// to start a web login process.
self.webLogin()
case .userFallback:
self.fabebookAuthentication()
default:
// Other error thrown by the framework.
}
}
}
}