Why my scrollView is nil? - xcode

Question

How can be possible that the scrollview is nil when using the first:#IBAction afegeixGrafic but when using #IBAction func button it isn't'?
I got the class GraficsBalancGlobalViewController which is subclass of the class GraficViewController
class GraficsBalancGlobalViewController: GraficViewController {
#IBAction func afegeixGrafic(sender: NSButton) {
addNewGrafic() // which is set on the GraficViewController
}
}
And when I perform the IBAction afegeixGrafic my program crashes on the line marked below:
class GraficViewController: NSViewController, GraficViewDataSource {
#IBAction func button(sender: NSButton) {
addNewGrafic()
}
func addNewGrafic() {
let frame = NSRect(x: 0, y: 0, width: self.view.bounds.width , height: self.view.bounds.width * 0.25)
let nouGrafic = GraficView(frame: frame)
scrollView.addSubview(nouGrafic) <---- BREAK here!
}
#IBOutlet weak var scrollView: NSView!
//...more code
}
The compiler says that:
fatal error: unexpectedly found nil while unwrapping an Optional value
but the button (IBAction) inside the GraficViewController works well!! So i suppose that the problem is related with the scrollView, but I have no idea of what can be.. It is initialized..
I try this too:
#IBOutlet weak var scrollView: NSView? {
didSet {
guard let sview = scrollView else {
addNewGrafic()
return // because scrollView is nil for some reason, but don't work
}
}
}
Full code:
class GraficsBalancGlobalViewController: GraficViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do view setup here.
}
#IBAction func afegeixGrafic(sender: NSButton) {
//performSegueWithIdentifier("Nou Grafic", sender: nil)
//let viewController = storyboard!.instantiateControllerWithIdentifier(identifier!) as! GraficsBalancGlobalViewController
addNewGrafic()
}
#IBAction func eliminaGrafic(sender: NSButton) {
}
}

Answer 1

Its nil because of how you instantiated GraficsBalancGlobalViewController. You set it up with a xib or a storyboard however you instantiated it without one.
Do this:
let viewController = storyboard.instantiateControllerWithIdentifier(identifier) as GraficsBalancGlobalViewController
Not This:
let viewController = GraficsBalancGlobalViewController()