Instantiate View Controller not working

Question

I'm trying to load another UIViewController so that I can get the data of the IBOutlets inside of it. I'm using Swift and Sprite-Kit. The UIViewController I am talking about is called GameViewController. It is the first thing that loads up in my game. Then it goes to my GameScene. This is where I am trying to instantiate my GameViewController. I want to do this because I am using a library called iCarousel and I want to animate it moving up from my GameScene. However, iCarousel can only be used on a UIViewController. So I want to call a function in GameViewController that will be called in GameScene. In this function, there is an NSLayoutConstraint that is used to move the carousel. Whenever I call this function, it says that its nil. Here is some of my code:

Inside my GameScene:

let storyboard: UIStoryboard = UIStoryboard.init(name: "Main", bundle: nil)
let firstViewController: GameViewController = storyboard.instantiateViewControllerWithIdentifier("Load-up") as! GameViewController
firstViewController.start()

Inside my GameViewController:

func start() {
     // Constraint
     top.constant = 100
     UIView.animateWithDuration(2){
        self.view.layoutIfNeeded()
    }
}

If you need more information, feel free to ask me. Thanks in advance!

Answer 1

That is because your view controller hasn't loaded its view hierarchy yet. viewController loads its view hierarchy only when something sends it a view message. The system will do this by its own when to put the view hierarchy on the screen. And it happens after calls like prepareForSegue:sender: and viewWillAppear: , loadView(), self.view.

So here your outlets are still nil since it is not loaded yet.

Just try to force your VC to call self.view and then access the properties/outlets.

Edit: Added sample code.

let storyboard = UIStoryboard.init(name: "Main", bundle: nil)
let firstViewController = storyboard.instantiateViewControllerWithIdentifier("Load-up") as! GameViewController
debugPrint("Printing for the sake of initializing view of VC: \(firstViewController.view)")
firstViewController.start()