ios - TouchID 取消应该关闭 View Controller

Question

对于我的应用程序，我需要使用 TouchID 保存它的一页。因此，用户有点被迫使用 TouchID，或者如果设备不支持它，则使用密码。如果用户取消TouchID认证，我想让View消失，回到 Root View 。我已经有那个工作了，但不知何故它不再工作了，我真的不知道为什么？!我只是复制到取消选项，其余的我想都无所谓。

func authenticateUser() {

    let context = LAContext()
    var error: NSError?
    let reasonString = "Authentication is needed to access your App"

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

        context.evaluatePolicy(LAPolicy.DeviceOwnerAuthenticationWithBiometrics, localizedReason: reasonString, reply: { (success, policyError) -> Void in
            if success {
                print("authentification successful")


                }

            }else{

                switch policyError!.code{
                case LAError.SystemCancel.rawValue:
                    print("Authentification was canceled by the system")
                case LAError.UserCancel.rawValue:
                    print("Authentication was canceled by user")
                    self.navigationController?.dismissViewControllerAnimated(true, completion: nil)
                //Yes I also tried popToRootViewController, still doesn't work    
}

Answer 1

evaluatePolicy 调用的文档说:

“策略评估完成时执行的回复 block 。此 block 在未指定的线程上下文中的框架内部的私有(private)队列上进行评估。”

所以问题是您正试图从错误的线程调用导航。您需要在 UI 线程上进行该调用。例如:

dispatch_async(dispatch_get_main_queue()) {
     // Navigation goes here
}