SpriteKit - Creating a timer

Question

How can I create a timer that fires every two seconds that will increment the score by one on a HUD I have on my screen? This is the code I have for the HUD:

Answer 1

Here's the full code to build a timer for SpriteKit with Xcode 9.3 and Swift 4.1

In our example the score label will be incrementd by 1 every 2 seconds. Here's final result

Good, let's start!

1) The score label

First of all we need a label

class GameScene: SKScene {
    private let label = SKLabelNode(text: "Score: 0")
}

2) The score label goes into the scene

class GameScene: SKScene {

    private let label = SKLabelNode(text: "Score: 0")

    override func didMove(to view: SKView) {
        self.label.fontSize = 60
        self.addChild(label)
    }
}

Now the label is at the center of the screen. Let's run the project to see it.

Please note that at this point the label is not being updated!

3) A counter

We also want to build a counter property which will hold the current value displayed by the label. We also want the label to be updated as soon as the counter property is changed so...

class GameScene: SKScene {

    private let label = SKLabelNode(text: "Score: 0")
    private var counter = 0 {
        didSet {
            self.label.text = "Score: \(self.counter)"
        }
    }

    override func didMove(to view: SKView) {
        self.label.fontSize = 60
        self.addChild(label)

        // let's test it!
        self.counter = 123
    }
}

4) The actions

Finally we want to build an action that every 2 seconds will increment counter

class GameScene: SKScene {

    private let label = SKLabelNode(text: "Score: 0")
    private var counter = 0 {
        didSet {
            self.label.text = "Score: \(self.counter)"
        }
    }

    override func didMove(to view: SKView) {
        self.label.fontSize = 60
        self.addChild(label)
        // 1 wait action
        let wait2Seconds = SKAction.wait(forDuration: 2)
        // 2 increment action
        let incrementCounter = SKAction.run { [weak self] in
            self?.counter += 1
        }
        // 3. wait + increment
        let sequence = SKAction.sequence([wait2Seconds, incrementCounter])
        // 4. (wait + increment) forever
        let repeatForever = SKAction.repeatForever(sequence)

        // run it!
        self.run(repeatForever)
    }
}