Va Visal Va Visal - 1 year ago 212
iOS Question

"switch(error!.code)" in canEvaluatePolicy function does not exist in Swift 3 (Xcode 8)

I'm converting below code to Swift 3.

if context.canEvaluatePolicy(LAPolicy.DeviceOwnerAuthenticationWithBiometrics, error:nil) {

// 2.
localizedReason: "Logging in with Touch ID",
reply: { (success : Bool, error : NSError? ) -> Void in

// 3.
dispatch_async(dispatch_get_main_queue(), {
if success {
self.performSegueWithIdentifier("dismissLogin", sender: self)

if error != nil {

var message : NSString
var showAlert : Bool

// 4.
switch(error!.code) {

Step 4 does not work anymore on Xcode 8, Swift 3. So I could not do the following cases:

switch(error!.code) {
case LAError.AuthenticationFailed.rawValue:
message = "There was a problem verifying your identity."
showAlert = true

Currently, it's seems there was no solution that I could find yet. Any suggestion, please let me know.

Thanks a lot!

Answer Source

First change your reply closure of evaluatePolicy method, in Swift 3 it is Error not NSError.

reply: { (success : Bool, error : Error? ) -> Void in

Second, change performSegue with identifier like this.

performSegue(withIdentifier: "dismissLogin", sender: self)

In Swift 3 you need to convert Error object to NSError or use _code with Error instance instead of code.

switch((error! as NSError).code)



You need to also change you dispatch syntax like this.

Dispatch.async.main {
    //write code
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