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Xcode – Why are my variable or cast empty in my iOS app?

I’m coding an app on Xcode for IOS and I’d like to send a variable to another ViewController that hasn’t appeared yet. The problem is that when I make a variable of my future ViewController like this :

guard let EndConfiguration = self.storyboard?.instantiateViewController(withIdentifier: EndConfiguration) as? EndConfiguration else
        {
            fatalError("Impossible d'acceder correctement au cellules des alarmes")
        }

And I’m trying to do this:

EndConfiguration.ModeleOutlet.text = Alarme.shared.Alarmes[indexPath.row].Modele

I get this error :

Fatal error: Unexpectedly found nil while implicitly unwrapping an
Optional value

I understood the Optionels but if I add a "?" after ModeleOutlet it will remove the error but the text remains unchanged in my other ViewController. I’m sure that the value I modify is full, don’t worry.

I’m replicating my problem because someone close it because there was already a solution when there wasn’t one at all.

Thank you in advance.

Tags:

2

Answers


  1. 0 
    try this 
guard let EndConfiguration = self.storyboard?.instantiateViewController(withIdentifier: EndConfiguration) as? EndConfiguration else
        {
            fatalError("Impossible d'acceder correctement au cellules des alarmes")
        }
_ = EndConfiguration.view
EndConfiguration.ModeleOutlet.text = Alarme.shared.Alarmes[indexPath.row].Modele
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  2. 0

    I am making the assumption that type of ModeleOutlet is a Label or of another type that may contain a text variable.

    If ModeleOutlet is indeed a label that is attached via storyboard, then I urge you to read up on the ViewController lifecycle. Here is a great article describing it : https://medium.com/good-morning-swift/ios-view-controller-life-cycle-2a0f02e74ff5

    Now, to answer your question specifically, you’ll likely want to create a separate variable within your view controller then set the text variable within the function, viewDidLoad.

    class EndConfiguration: UIViewController {
    public var sharedText: String?

    @IBOutlet var ModeleOutlet: UILabel?

    func viewDidLoad() {
        super.viewDidLoad()

        self.ModeleOutlet?.text = sharedText
    }

}
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