IOS - How to segue programmatically using swift

If your segue exists in the storyboard with a segue identifier between your two views, you can just call it programmatically using:

performSegue(withIdentifier: "mySegueID", sender: nil)

For older versions:

performSegueWithIdentifier("mySegueID", sender: nil)

You could also do:

presentViewController(nextViewController, animated: true, completion: nil)

Or if you are in a Navigation controller:

self.navigationController?.pushViewController(nextViewController, animated: true)

You can use NSNotification

Add a post method in your custom class:

NSNotificationCenter.defaultCenter().postNotificationName("NotificationIdentifier", object: nil)

Add an observer in your ViewController:

NSNotificationCenter.defaultCenter().addObserver(self, selector: "methodOFReceivedNotication:", name:"NotificationIdentifier", object: nil)

Add function in you ViewController:

func methodOFReceivedNotication(notification: NSNotification){
    self.performSegueWithIdentifier("yourIdentifierInStoryboard", sender: self)
}

You can use segue like this:

self.performSegueWithIdentifier("push", sender: self)
override func prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!) {
    if segue.identifier == "push" {

    }
}

If your segue exists in the storyboard with a segue identifier between your two views, you can just call it programmatically using

self.performSegueWithIdentifier("yourIdentifierInStoryboard", sender: self)

If you are in Navigation controller

let viewController = YourViewController(nibName: "YourViewController", bundle: nil)        
self.navigationController?.pushViewController(viewController, animated: true)

I will recommend you for second approach using navigation controller.

Swift 3 - Also works with SpriteKit

You can use NSNotification.

Example:

1.) Create a segue in the storyboard and name the identifier "segue"

2.) Create a function in the ViewController you are segueing from.

func goToDifferentView() {

    self.performSegue(withIdentifier: "segue", sender: self)

}

3.) In the ViewDidLoad() of your ViewController you are segueing from create the observer.

NotificationCenter.default.addObserver(self, selector: #selector(goToDifferentView), name: "segue" as NSNotification.Name, object: nil)

Update - Last time I used this I had to change the .addObserver call to the following code to silence the errors.

NotificationCenter.default.addObserver(self, selector: #selector(goToDifferentView), name: NSNotification.Name(rawValue: "segue"), object: nil)

4.) In the ViewController or Scene you are segueing to, add the Post Method wherever you want the segue to be triggered.

NotificationCenter.default.post(name: "segue" as NSNotification.Name, object: nil)

Update - Last time I used this I had to change the .post call to the following code to silence the errors.

NotificationCenter.default.post(NSNotification(name: NSNotification.Name(rawValue: "segue"), object: nil) as Notification)

What you want to do is really important for unit testing. Basically you need to create a small local function in the view controller. Name the function anything, just include the performSegueWithIndentifier.

func localFunc() {
    println("we asked you to do it")
    performSegueWithIdentifier("doIt", sender: self)
}

Next change your utility class FBManager to include an initializer that takes an argument of a function and a variable to hold the ViewController's function that performs the segue.

public class UtilClass {

    var yourFunction : () -> ()

    init (someFunction: () -> ()) {
        self.yourFunction = someFunction
        println("initialized UtilClass")
    }

    public convenience init() {
        func dummyLog () -> () {
            println("no action passed")
        }
        self.init(dummyLog)
    }

    public func doThatThing() -> () {
        // the facebook login function
        println("now execute passed function")
        self.yourFunction()
        println("did that thing")
    }
}

(The convenience init allows you to use this in unit testing without executing the segue.)

Finally, where you have //todo: segue to the next view???, put something along the lines of:

self.yourFunction()

In your unit tests, you can simply invoke it as:

let f = UtilClass()
f.doThatThing()

where doThatThing is your fbsessionstatechange and UtilClass is FBManager.

For your actual code, just pass localFunc (no parenthesis) to the FBManager class.

You can do this thing using performSegueWithIdentifier function.

Syntax :

func performSegueWithIdentifier(identifier: String, sender: AnyObject?)

Example :

 performSegueWithIdentifier("homeScreenVC", sender: nil)

This worked for me.

First of all give the view controller in your storyboard a Storyboard ID inside the identity inspector. Then use the following example code (ensuring the class, storyboard name and story board ID match those that you are using):

let viewController:
UIViewController = UIStoryboard(
    name: "Main", bundle: nil
).instantiateViewControllerWithIdentifier("ViewController") as UIViewController
// .instantiatViewControllerWithIdentifier() returns AnyObject!
// this must be downcast to utilize it

self.presentViewController(viewController, animated: false, completion: nil)

For more details see http://sketchytech.blogspot.com/2012/11/instantiate-view-controller-using.html best wishes