Calling upon the previous view controller in Swift

Question

I am trying to call upon the root controller and I don't know the code to call upon it. I'm using a conditional and which will check what the previous view controller was, and a block of code will run depending on what it was. Here is my code:

SecondViewController

override func viewDidLoad ( ) {
     super.viewDidLoad ( )

     let previousController = storyboard!.instantiateViewControllerWithIdentifier ("firstViewController") as? FirstViewController

     //HELP IN LINE BELOW
     //if root view controller == previousController {
              //run some code
     //}
}

`instantiateViewControllerWithIdentifier` will create each time a new view controller. What are you trying to achieve? — Moxy, May 11 '15 at 20:42
possible duplicate of [How do you share data between view controllers and other objects in Swift?](http://stackoverflow.com/questions/29734954/how-do-you-share-data-between-view-controllers-and-other-objects-in-swift) — nhgrif, May 11 '15 at 23:19

Danny Bravo · Accepted Answer · 2016-07-03T06:55:49.253

let stack = self.navigationController.viewControllers
if (stack.count > 1) {
    let previousController = stack[stack.count-2]
}

Or if you don't have a navigation controller

let previousController = self.presentingViewController

Also, just to be clear, the root view controller will be the first view controller in the stack, i.e:

self.navigationController.viewControllers.firstObject

or

var previousController : UIViewController = self
var rootController : UIViewController?
do {
    var rootViewController = previousController
    var previousController = rootViewController.presentingViewController
} while (previousController != nil)

Calling upon the previous view controller in Swift

1 Answers1