为什么要执行我的检定？

Question

In my iOS app, I have a log in Button to go from one viewController to another, which uses the following function:

@IBAction func logInButton(sender: AnyObject) {
    if loggedIn == true {
        // user is signed in
        print("A user is logged in.")
        uid = user.uid
        self.currentUser(uid)
        self.performSegueWithIdentifier("logIn", sender: sender)
    } else {
        print("No current user.")
        let anim = CAKeyframeAnimation( keyPath:"transform" )
        anim.values = [
            NSValue( CATransform3D:CATransform3DMakeTranslation(-10, 0, 0 ) ),
            NSValue( CATransform3D:CATransform3DMakeTranslation( 10, 0, 0 ) )
        ]
        anim.autoreverses = true
        anim.repeatCount = 2
        anim.duration = 7/100
        self.passwordTextField.layer.addAnimation( anim, forKey:nil )
        self.welcomeTextLabel.hidden = false
        self.welcomeTextLabel.text = "Please sign in first"
    }
}

There's a function which runs within viewDidLoad() that updates the loggedIn value. I've tested this function when loggedIn == false (based on console output), and the app crashes based on code that executes on the subsequent viewController . I know why it crashes (no user data) but I don't know why the segue is being performed at all.

If you need more code to diagnose please ask.

Answer 1

In your storyboard you need to create the segue between two view controllers instead of button to DestinationViewController.

Please remove that segue and create one segue from your LoginViewController to your DestinationViewController.