UISwitch().setOn does not work (seemly) - ios

Question

here is the uiswitch valueChange action
#IBAction func swichTouchIdState(sender: UISwitch) {
print("newState:\(sender.on)")
if sender.on == false {
AuthenticationSetter.touchIdAuthentication() {
isSuccess, error in
if isSuccess == true {
AuthenticationSetter.setAuthenticationSwitchUserDefault(false)
} else {
sender.setOn(true, animated: true)
}
if let laError = error as? LAError {
print("error happened in authenticating: \(laError)")
switch laError {
case .AppCancel:
print("App Cancel")
self.touchIdSwitch.setOn(true, animated: true)
break
case .SystemCancel:
print("System Cancel")
self.touchIdSwitch.setOn(true, animated: true)
break
case .UserCancel:
print("User Cancel")
dispatch_async(dispatch_get_main_queue()) {
self.touchIdSwitch.setOn(true, animated: false)
}
break
default:
break
}
} else {
print("no error")
}
}
} else {
AuthenticationSetter.setAuthenticationSwitchUserDefault(true)
}
}
and here is the AuthenticationSetter.touchIdAuthentication function
class func touchIdAuthentication(doAfterAuthentication: (Bool, NSError?) -> Void) {
let laContext = LAContext()
var error: NSError?
if laContext.canEvaluatePolicy(LAPolicy.DeviceOwnerAuthenticationWithBiometrics, error: &error) {
laContext.evaluatePolicy(LAPolicy.DeviceOwnerAuthenticationWithBiometrics, localizedReason: "TouchID Authentication", reply: doAfterAuthentication)
} else {
print("device don't support touchId")
}
}
and when I touch cancel at the touchid window， the "User Cancel" is printed but the switch doesn't become on.
I create a new demoViewController that has a UISwitch and a button
when the buttonpressed this function is called : demoSwitch.setOn(demoSwitch.on, true)
and It run just well!!!! can any ios master help me!