Background Image not changing in Swift

Question

So basically I am trying to have this app change its background when a button is pushed. The way I'm trying to do it is to set a variable 0 and if the button is pushed it will either make it 1 less or 1 more. Currently, the background does change if I manually change the variable in the class but it does not change when I tried to use the buttons.

This is my code for my changing the background ///////////////////////////////////////////////////

 let gameVC = SelectCharViewController()
    
    
    override func didMove(to view: SKView) {
        
        let backgroundCheck2 = gameVC.getter()
        
        
        physicsWorld.contactDelegate = self
        
      //  var backgroundImage = SKSpriteNode(imageNamed: "background")
        if(backgroundCheck2 == 0){
            let backgroundImage = SKSpriteNode(imageNamed: "background")
            backgroundImage.size = CGSize(width: frame.size.width, height: frame.size.height)
            backgroundImage.position = CGPoint(x: frame.midX, y: frame.midY)
            backgroundImage.zPosition = -1
            addChild(backgroundImage)
            
        }
        else{
            let backgroundImage = SKSpriteNode(imageNamed: "background2")
            backgroundImage.size = CGSize(width: frame.size.width, height: frame.size.height)
            backgroundImage.position = CGPoint(x: frame.midX, y: frame.midY)
            backgroundImage.zPosition = -1
            addChild(backgroundImage)
        }

And this is my code for the buttons

import UIKit

class SelectCharViewController: UIViewController {
    
    public var backgroundCheck = 0

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }
    
    @IBAction func nightShift(_sender: UIButton){
        print(backgroundCheck)
        self.backgroundCheck+=1;
        print(backgroundCheck)
    }
    
    @IBAction func dayShift(_sender: UIButton){
        print(backgroundCheck)
        self.backgroundCheck-=1;
        print(backgroundCheck)
    }
    
    func getter() -> Int{
        return self.backgroundCheck
    }
    

    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        // Get the new view controller using segue.destination.
        // Pass the selected object to the new view controller.
    }
    */

}

Answer 1

There are probably a number of things you could be doing differently (using a boolean instead of an integer, for example).

But I suspect that you aren't seeing the desired behavior because your image-changing code is located in didMove(to:), which is only called when the scene is first presented.

To make it work on button press, you could move that code to your own function, like this:

func changeBackground(backgroundCheck2: Int) {
        if backgroundCheck2 == 0 {
            let backgroundImage = SKSpriteNode(imageNamed: "background")
            backgroundImage.size = CGSize(width: frame.size.width, height: frame.size.height)
            backgroundImage.position = CGPoint(x: frame.midX, y: frame.midY)
            backgroundImage.zPosition = -1
            addChild(backgroundImage)
        } else {
            let backgroundImage = SKSpriteNode(imageNamed: "background2")
            backgroundImage.size = CGSize(width: frame.size.width, height: frame.size.height)
            backgroundImage.position = CGPoint(x: frame.midX, y: frame.midY)
            backgroundImage.zPosition = -1
            addChild(backgroundImage)
        }
}

Then, call changeBackground(backgroundCheck2:) from your button logic, wherever that may be.

You'll need a single instance of your scene. Something like this:

struct Something {
    static var scene = GameScene()
}

So, in this case, you'd call your function like this:

Something.scene.changeBackground(backgroundCheck2: 1)