how do I switch between NSViewControllers using NSPageController?

Question

I have had bad luck finding any examples on the web that closely match what I am trying to do. I am trying to using NSPageController to view and switch between multiple NSPageControllers. My steps.

1. I create a new OS X swift project
2. I add an object to the ViewController and make it of NSPageController class.
3. I add two buttons, one I label "Next" and the other one I label "Back" for the transitions.
4. I link the buttons to the NSPageController object as navigateForward and navigateBack actions.
5. I create an outlet in the custom NSViewController class for the NSPageController object and add the specific NSPageController delegate methods.

6. I add two additional view controllers in storyboard and create an identifier for them to reference back in my custom view controller class: Wizard1, Wizard2.

   import Cocoa

   class ViewController: NSViewController, NSPageControllerDelegate {

   @IBOutlet var myPageController: NSPageController!
   override func viewDidLoad() {
       super.viewDidLoad()
       let vc1: AnyObject? = self.storyboard!.instantiateControllerWithIdentifier("Wizard1")
       let vc2: AnyObject? = self.storyboard!.instantiateControllerWithIdentifier("Wizard2")
       self.myPageController.arrangedObjects.append(vc1!)
       self.myPageController.arrangedObjects.append(vc2!)
       // Do any additional setup after loading the view.
   }
   override init?(nibName nibNameOrNil: String?, bundle nibBundleOrNil: NSBundle?) {
       myPageController = NSPageController()
       super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil?)
   }
   
    required init?(coder aDecoder: NSCoder) {
   myPageController = NSPageController()
   super.init(coder:aDecoder)
   }
   
   override var representedObject: AnyObject? {
       didSet {
       // Update the view, if already loaded.
       }
   }
   
   func pageController(pageController: NSPageController, identifierForObject object: AnyObject!) -> String! {
       return "View"
   }
   
   func pageController(pageController: NSPageController, viewControllerForIdentifier identifier: String!) -> NSViewController! {
       let vc1: AnyObject? = self.storyboard!.instantiateControllerWithIdentifier("Wizard1")
       return vc1 as NSViewController
   
   }
   func pageController(pageController: NSPageController, prepareViewController viewController: NSViewController!, withObject object: AnyObject!) {
       viewController.representedObject = object
   }
   func pageControllerDidEndLiveTransition(pageController: NSPageController) {
       pageController.completeTransition()
   }
   func pageControllerWillStartLiveTransition(pageController: NSPageController) {
   self.presentViewControllerAsModalWindow(self.storyboard?.instantiateControllerWithIdentifier("Wizard2") as NSViewController)
   
   }
   

   }

The error I get when pressing the Next button is:

-[NSNib initWithNibNamed:bundle:] could not load the nibName: NSPageController in bundle (null).

Answer 1

Perhaps you are trying to load a nib with the wrong name in AppDelegate.m or wherever you are initializing your page controller.

Otherwise you have missed creating a .xib file and to name it NSPageController. When creating a Cocoa Touch Class there is a checkbox to also create an xib file for your class if needed.

Answer 2

This line is responsible for the error:

myPageController = NSPageController()

You're trying to initialize a view controller without a nib, that's why it does not work. By default the NSViewController's name is taken to identify the nib that corresponds to it. In your case it is "NSPageController".