Touch ID API responsive is very slow - ios

Question

I have followed the guidelines and also the example for Touch ID API from Apple documentation. I have used the example in my applications. I could able to login using Touch ID. But the problem is its responsive is very very slow. After I put my finger on the Touch ID , at least 10 seconds I have to wait to get verify success/failure. I have used the code in app delegate file. I have also tested with different apps but the result is the same "delayed response". Guys please help me in this case.

Answer 1

LAContext *myContext = [[LAContext alloc] init];
NSError *authError = nil;
NSString *myLocalizedReasonString = <#String explaining why app needs authentication#>;
if ([myContext canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&authError]) {
[myContext evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics
localizedReason:myLocalizedReasonString
reply:^(BOOL success, NSError *error) {
if (success) {
// User authenticated successfully, take appropriate action
dispatch_async(dispatch_get_main_queue(), ^{
// write all your code here
});
} else {
// User did not authenticate successfully, look at error and take appropriate action
switch (error.code) {
case LAErrorAuthenticationFailed:
NSLog(#"Authentication Failed");
break;
case LAErrorUserCancel:
NSLog(#"User pressed Cancel button");
break;
case LAErrorUserFallback:
NSLog(#"User pressed \"Enter Password\"");
break;
default:
NSLog(#"Touch ID is not configured");
break;
}
NSLog(#"Authentication Fails");
}
}];
} else {
// Could not evaluate policy; look at authError and present an appropriate message to user
}

Answer 2

You have to display the alertviews in the main thread with
dispatch_async(dispatch_get_main_queue(), ^{
//update ui
});
LAContext *context = [[LAContext alloc] init];
NSError *error = nil;
if ([context canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&error]) {
// Authenticate User
NSError *error = nil;
if ([context canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&error]) {
[context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics
localizedReason:#"Please verify that you are the device owner in order to place the order"
reply:^(BOOL success, NSError *error) {
dispatch_async(dispatch_get_main_queue(), ^{
if (error) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Error"
message:#"There was a problem verifying your identity."
delegate:nil
cancelButtonTitle:#"Ok"
otherButtonTitles:nil];
[alert show];
return;
}
if (success) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Success"
message:#"You are the device owner!"
delegate:nil
cancelButtonTitle:#"Ok"
otherButtonTitles:nil];
[alert show];
} else {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Error"
message:#"You are not the device owner."
delegate:nil
cancelButtonTitle:#"Ok"
otherButtonTitles:nil];
[alert show];
}
});
}];
}
} else {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Error"
message:#"Your device cannot authenticate using TouchID."
delegate:nil
cancelButtonTitle:#"Ok"
otherButtonTitles:nil];
[alert show];
}

Answer 3

As other said, you have to do UI thing on the main thread, for Swift 3.0 it's:
myContext.evaluatePolicy(LAPolicy.deviceOwnerAuthenticationWithBiometrics, localizedReason: myLocalizedReasonString) { (success, evaluateError) in
DispatchQueue.main.async {
if (success) {
//success
} else {
//failure
}
}
}