Pass data from ViewController to class

Question

I'm quite new to Swift and I'm struggling with this issue. I want to pass the size and point of squareImage to a different swift file in my project using setSquareRec.

View Controller:

class ViewController: UIViewController, SceneDelegate {

    @IBOutlet var squareImage: UIImageView!

    var scene = Scene()

    func setSquareRec() {
        scene.x = Int(squareImage.bounds.minX)
        scene.y = Int(squareImage.bounds.minY)
        scene.width = Int(squareImage.bounds.width)
        scene.height = Int(squareImage.bounds.height)
    }

    ...

}

The class:

protocol SceneDelegate{
    func setSquareRec()
}

class Scene: SKScene {

    var width = 0
    var height = 0
    var x = 0
    var y = 0

    ...

    let ARViewController = ViewController()
    ARViewController.setSquareRec()

}

It gives me the error Thread 5: Fatal error: Unexpectedly found nil while unwrapping an Optional value in the first line ( scene.width = Int(sqareImage.bounds.minX) ) of the function setSquareRec

How is it possible that is has no value?! And how is it possible to pass it to another class? I looked at so many solutions but none of them worked or I don't get it.

That is because you called setSquareRec() before the views are loaded in the viewController. — Marwen Doukh
– Marwen Doukh, Commented Jan 23, 2019 at 14:37
@MarwenDoukh when are they loaded? I couldn't find the order of how swift compiles the code because there's no main function. As you notice I'm a noob at swift — Caddarina
– Caddarina, Commented Jan 23, 2019 at 14:38

Arthur · Accepted Answer · 2019-01-23 14:36:40Z

1

You instantiate your view controller with let ARViewController = ViewController().

Try inflating it from a storyboard.

Feel free to ask if it isn't clear.

answered Jan 23, 2019 at 14:36

Arthur

4201 gold badge5 silver badges13 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Caddarina Over a year ago

I'm sorry, but it's not clear to me. What does inflating mean? I'm not a native speaker (and especially no professional programmer)

Khushal Dugar · Accepted Answer · 2019-01-23 14:50:56Z

1

The way you are using your delegate is wrong infact you are not using the delegate itselg. Kindly look at the approach below.

import UIKit

class ViewController: UIViewController, SceneDelegate {

    @IBOutlet var squareImage: UIImageView!

    var scene = Scene()

    override func viewDidLoad() {
        super.viewDidLoad()

        //set delegate for scene as this delegate
        scene.sceneDelegate = self
    }

    func setSquareRec() {
        scene.x = Int(squareImage.bounds.minX)
        scene.y = Int(squareImage.bounds.minY)
        scene.width = Int(squareImage.bounds.width)
        scene.height = Int(squareImage.bounds.height)
    }
}

protocol SceneDelegate{
    func setSquareRec()
}

class Scene: SKScene {

    var width = 0
    var height = 0
    var x = 0
    var y = 0
    var sceneDelegate: SceneDelegate?

    ...
    //call this delegate method like this
    //This will call the setSquareRec method to any class who is set as delegate
    sceneDelegate.setSquareRec()
    ...
}

not tested kindly test let me know incase of any issue

answered Jan 23, 2019 at 14:50

Khushal Dugar

2314 silver badges13 bronze badges

3 Comments

Caddarina Over a year ago

Thank you. I tried your code and it gave me the same error. I also tried another suggestion by adding self.loadView() into the first line of the function setSquareRec() additionally to your code. But it failed also...

Khushal Dugar Over a year ago

please you share the code where you are loading the view controller

Caddarina Over a year ago

Okay I think there is the problem. I never initialize a ViewController except once in the class Scene (as you can see above) so I can use the setSquareRec function. A friend of mine gave me his code for an AR App. In his code he never initializes a ViewController and the App still worked.

Collectives™ on Stack Overflow

Pass data from ViewController to class

2 Answers 2

1 Comment

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related