Share a variable between swift files - ios

Question

Explanation
My question is pretty straight forward: how do I print a variable from GameScene on GameViewController?
Code
I created this code below so it's easier to get the idea.
GameScene.swift
import SpriteKit
class GameScene: SKScene {
var variable = Int()
override func didMoveToView(view: SKView) {
/* Setup your scene here */
variable = 50
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
NSNotificationCenter.defaultCenter().postNotificationName("calledFromGameSceneVC", object: nil)
}
}
GameViewController.swift
import UIKit
import SpriteKit
class GameViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Set view size.
let scene = GameScene(size: view.bounds.size)
// Configure the view.
let skView = view as! SKView
skView.showsFPS = true
skView.showsNodeCount = true
/* Sprite Kit applies additional optimizations to improve rendering performance */
skView.ignoresSiblingOrder = true
/* Set the scale mode to scale to fit the window */
scene.scaleMode = .ResizeFill
skView.presentScene(scene)
//------------------------------//
//Register observer
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(GameViewController.calledFromGameScene), name: "calledFromGameSceneVC", object: nil)
}
func calledFromGameScene(){
//Print variable
let scene = GameScene(size: view.bounds.size)
print("My variable from GameScene is: ", scene.variable)
}
}
Sorry for the brief explanation.
Thanks in advance,
Luiz.

Answer 1

The type of inter-object communication you are trying to achieve is probably best addressed through a delegation pattern using a protocol:
GameScene.swift
import SpriteKit
protocol GameSceneDelegate {
func calledFromGameScene(scene: GameScene)
}
class GameScene: SKScene {
var variable = Int()
var gameDelegate: GameSceneDelegate?
override func didMoveToView(view: SKView) {
/* Setup your scene here */
variable = 50
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
gameDelegate?.calledFromGameScene(self)
}
}
GameViewController.swift
class GameViewController: UIViewController, GameSceneDelegate {
override func viewDidLoad() {
super.viewDidLoad()
// Set view size.
let scene = GameScene(size: view.bounds.size)
// Configure the view.
let skView = view as! SKView
skView.showsFPS = true
skView.showsNodeCount = true
/* Sprite Kit applies additional optimizations to improve rendering performance */
skView.ignoresSiblingOrder = true
/* Set the scale mode to scale to fit the window */
scene.scaleMode = .ResizeFill
/* Set the delegate */
scene.gameDelegate = self
skView.presentScene(scene)
}
func calledFromGameScene(scene:GameScene){
//Print variable
print("My variable from GameScene is: ", scene.variable)
}
}
Note that you can't use the property name delegate on your GameScene as SKScene already has a delegate property