iOS8 check if device has Touch ID

Question

LAContext has method to check if device can evaluate touch ID and gives error message. Problem is that same error message \"LAErrorPasscodeNotSet\" is given by system in two cas

Answer 1

Here you can check, Touch-ID and Face-ID both (with iOS 11+)

Use property biometryType of LAContext to check and evaluate available biometric policy. (For a passcode authentication , when biometric fails, use: LAPolicyDeviceOwnerAuthentication)

Try this and see:

Objective-C:

LAContext *laContext = [[LAContext alloc] init];

NSError *error;


// For a passcode authentication , when biometric fails, use: LAPolicyDeviceOwnerAuthentication
//if ([laContext canEvaluatePolicy: LAPolicyDeviceOwnerAuthentication error:&error]) {
if ([laContext canEvaluatePolicy: LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&error]) {    
    if (error != NULL) {
        // handle error
    } else {

        if (@available(iOS 11, *)) {
            if (laContext.biometryType == LABiometryTypeFaceID) {
                //localizedReason = "Unlock using Face ID"
                NSLog(@"FaceId support");
            } else if (laContext.biometryType == LABiometryTypeTouchID) {
                //localizedReason = "Unlock using Touch ID"
                NSLog(@"TouchId support");
            } else {
                //localizedReason = "Unlock using Application Passcode"
                NSLog(@"No biometric support or Denied biometric support");
            }
        } else {
            // Fallback on earlier versions
        }


        [laContext evaluatePolicy: LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:@"Test Reason" reply:^(BOOL success, NSError * _Nullable error) {

            if (error != NULL) {
                // handle error
            } else if (success) {
                // handle success response
            } else {
                // handle false response
            }
        }];
    }
}

Swift:

let laContext = LAContext()
var error: NSError?
let biometricsPolicy = LAPolicy.deviceOwnerAuthentication //LAPolicy.deviceOwnerAuthenticationWithBiometrics

if laContext.isCredentialSet(LACredentialType.applicationPassword) {
    print("Passsword is set")
}

let localizedFallbackTitle = "Unlock Using Device Passcode"
let localizedCancelTitle = "Use Application Passcode"
if (laContext.canEvaluatePolicy(biometricsPolicy, error: &error)) {

    if let laError = error {
        print("laError - \(laError)")
        return
    }



    //print("biometricsPolicy - \(biometricsPolicy.rawValue)")

    UINavigationBar.appearance().tintColor = UIColor.red


    var localizedReason = "My Reason to be displayed on face id prompt"
    if #available(iOS 11.0, *) {
        if (laContext.biometryType == LABiometryType.faceID) {
            //localizedReason = "Unlock using Face ID"
            print("FaceId support")
        } else if (laContext.biometryType == LABiometryType.touchID) {
            //localizedReason = "Unlock using Touch ID"
            print("TouchId support")
        } else {
            //localizedReason = "Unlock using Application Passcode"
            print("No Biometric support")
        }
    } else {
        // Fallback on earlier versions
    }

    laContext.localizedFallbackTitle = localizedFallbackTitle
    laContext.localizedCancelTitle = localizedCancelTitle
    //laContext.localizedReason = "test loc reason"
    laContext.evaluatePolicy(biometricsPolicy, localizedReason: localizedReason, reply: { (isSuccess, error) in

        DispatchQueue.main.async(execute: {

            if let laError = error {
                print("laError - \(laError)")
            } else {
                if isSuccess {
                    print("sucess")
                } else {
                    print("failure")
                }
            }

        })
    })
}