Xcode: instantiating a view controller with custom variable

Question

So I want to instantiate a view controller from storyboard and change its static variables.

This is "vc1" - the view controller to be instantiated:

import UIKit

class vc1: UIViewController {
    @IBOutlet weak var lbl_title: UILabel!
    
    static var title = "initial value"
    
    override func viewDidLoad() {
        super.viewDidLoad()

        lbl_title.text = vc1.title
    }
}

And this is my root vc.

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var btn_go: UIButton!
    
    @IBAction func btn_gogogo(_ sender: Any) {
        
        let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "vc1") as! vc1
        
        vc.title = "bla"

        self.present(vc, animated: true, completion: nil)
    }

}

Here I'm trying to change the static variable of the view controller that I just instantiated, with no effect. The variable ( in my case 'title' ) is always stuck to its initial value.

What is the problem here?

Best

Mark

In the code you've shared, there's no reason for it to be static — jnpdx
– jnpdx, Commented Jan 9, 2023 at 16:07
you are right... understood :-) but my problem still remains unchanged — mtacki
– mtacki, Commented Jan 9, 2023 at 16:09
Have you tried wrapping the line where you set the title inside of a “DispatchQueue.main.async”? — nhiddink
– nhiddink, Commented Jan 9, 2023 at 16:12

DonMag · Accepted Answer · 2023-01-09 16:44:59Z

1

Don't try to override the view controller's title property. Instead, create your own:

class vc1: UIViewController {
    @IBOutlet weak var lbl_title: UILabel!
    
    var myTitle = "initial value"
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        lbl_title.text = myTitle
    }
}

class ViewController: UIViewController {
    
    @IBOutlet weak var btn_go: UIButton!
    
    @IBAction func btn_gogogo(_ sender: Any) {
        
        let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "vc1") as! vc1
        
        vc.myTitle = "bla"
        
        self.present(vc, animated: true, completion: nil)
    }
    
}

answered Jan 9, 2023 at 16:44

DonMag

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