CODEWITHSUNDEEP
iosiphoneswiftsegue
zottirik
zottirik

Reputation: 82

Swift segue fatal error

In ViewController:

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if (segue.identifier == "Segue") {
        var svc = segue.destinationViewController as! ViewController2;

        svc.vericik = self.vericik   
    }
}


@IBAction func gotoView2(sender: AnyObject) {
    self.performSegueWithIdentifier("Segue", sender: self)
    self.presentViewController(ViewController2(), animated: true, completion: nil)
}

In ViewController2:

var vericik: String!

    @IBOutlet weak var VeriYeri: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
        VeriYeri.text = vericik
    }

When, I click button on ViewController, ViewController2 page comes to screen and I can see segue data which come from ViewController. But after that, an error occurs:

fatal error: unexpectedly found nil while unwrapping an Optional value

Where am I doing wrong?

Upvotes: 1

Views: 433

Answers (3)

vacawama
vacawama

Reputation: 154513

Your problem is this line:

self.presentViewController(ViewController2(), animated: true, completion: nil)

This line of code is creating a second ViewController2. The first one was created for you when you did self.performSegueWithIdentifier("Segue", sender: self). This second ViewController2 never gets initialized, so its vericik property is still nil when viewDidLoad runs and implicitly unwraps the optional with VeriYeri.text = vericik (because vericik is declared as String!).

To fix the problem, simply delete this line of code:

self.presentViewController(ViewController2(), animated: true, completion: nil)

It is not needed. The segue creates ViewController2 for you, and you initialize it in prepareForSegue, and then the segue presents ViewController2. There's absolutely no need for you to call presentViewController when using segues.

Upvotes: 1

the_pantless_coder
the_pantless_coder

Reputation: 2297

You need to check that your string is not nil. Try this.

ViewController2

 override func viewDidLoad() {
        super.viewDidLoad()
           if vericik != nil {
            //String is not nil, set textfield/label whatever
            VeriYeri.text = vericik
            }
    }

ViewController

if (segue.identifier == "Segue") {
    var svc = segue.destinationViewController as! ViewController2;
         if self.vericik != nil {
              //String is not nil. All is good :)
              svc.vericik = self.vericik
          } else {
             //String is nil, do something...maybe set default text
             svc.vericik = "some text"
          }
}

Upvotes: 0

scott
scott

Reputation: 1194

Somehow, you are setting your vericik variable to nil. Can you print that value before you try setting it before the segue? If it's nil, don't set it as the text, because that's causing the crash.

Upvotes: 0

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