斯威夫特变量不持有价值或以某种方式重置自己

Question

I am trying to keep score in a game which has different point values associated with different things. The user has to touch things in the game to get the points. However the score is not being calculated accurately.

I have determined that the score associated which each element in the game is being stored properly in a variable called ballValue . The variable currentScore is used to hold the score and then I'm using a SKLabelNode to display the value of currentScore .

currentScore is initialized with a value of 0 and is updated with its current value plus ballValue when a user touches a ball.

Update to show code and context

class ChallengeScene: SKScene, GKGameCenterControllerDelegate {

    // MARK: Ball Data
    var randomBallType : Int = 0
    var ballValue : Int = 0

    // MARK: HUD
    var scoreLabel = SKLabelNode(fontNamed: "Impact")
    var timeLabel = SKLabelNode(fontNamed: "Impact")

    var currentScore : Int = 0 {
        didSet {
            self.scoreLabel.text = "\(self.currentScore)"
            GameHandler.sharedInstance.score = currentScore
        }
    }

    // MARK: Initial Setup
    func createHUD() {
    ... UNRELATED HUD STUFF...
        currentScore = 0
    }

    // MARK: Gameplay Setup
    func createBall(forTrack track: Int) {
        setupTracks()

        randomBallType = GKRandomSource.sharedRandom().nextInt(upperBound: 9)

        switch randomBallType {
        case 0:
            player = SKSpriteNode(imageNamed: "blueOne")
            ballSpeed = 0.008
            ballValue = 1
        case 1:
            player = SKSpriteNode(imageNamed: "minusThree")
            ballSpeed = 0.008
            ballValue = -3
        case 2:
            player = SKSpriteNode(imageNamed: "minusFive")
            ballSpeed = 0.008
            ballValue = -5
        case 3:
            player = SKSpriteNode(imageNamed: "purpleThree")
            ballSpeed = 0.008
            ballValue = 3
        case 4:
            player = SKSpriteNode(imageNamed: "greenFive")
            ballSpeed = 0.008
            ballValue = 5
        case 5:
            player = SKSpriteNode(imageNamed: "blackTen")
            ballSpeed = 0.008
            ballValue = 10
        default:
            player = SKSpriteNode(imageNamed: "blueOne")
            ballSpeed = 0.008
            ballValue = 1
        }

        player?.name = "BALL"
        player?.size = CGSize(width: 100, height: 100)
        player?.physicsBody?.linearDamping = 0

        ...UNRELATED BALL STUFF...

        self.addChild(player!)
    }

    // MARK: Overrides
    override func didMove(to view: SKView) {

        createHUD()
        launchGameTimer()

        self.run(SKAction.repeatForever(SKAction.sequence([SKAction.run {
            self.createBall(forTrack: self.track)
            }, SKAction.wait(forDuration: 1)])))

    }

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        for touch in touches {
            let location = touch.location(in: self)
            let node = self.nodes(at: location).first

            if node?.name == "BALL" {
                currentScore = currentScore + ballValue
                node?.removeFromParent()
            }
        }

    }


    override func update(_ currentTime: TimeInterval) {

        // GAME TIMER RELATED STUFF

    }
}

I think I know where the problem happens (in the touches override), I just don't understand why it is happening. If you could help in anyway that would be awesome

Answer 1

You have a single ballValue property. Every time you spawn a new ball, you set ballValue as appropriate for that newly-created ball . What about all the other existing balls? A touch on any of them will also be worth that same ballValue .

When a ball is touched, you need to know the proper value for the touched ball , which may be different than the value of the most-recently-created ball. What you probably want to do is create a subclass of SKSpriteNode that represents a ball, and holds its own value:

class BallNode: SKSpriteNode {
    let value: Int

    init(imageName: String, speed: CGFloat, value: Int) {
        let texture = SKTexture(imageNamed: imageName)
        self.value = value
        super.init(texture: texture, color: .init(white: 1, alpha: 0), size: texture.size())
        self.speed = speed
    }

    required init(coder decoder: NSCoder) { fatalError() }
}

Create the balls like this:

func createBall(forTrack track: Int) {

// setupTracks()

    randomBallType = GKRandomSource.sharedRandom().nextInt(upperBound: 9)

    let ball: BallNode
    switch randomBallType {
    case 0: ball = BallNode(imageNamed: "blueOne", speed: 0.008, value: 1)
    case 1: ball = BallNode(imageNamed: "minusThree", speed: 0.008, value: -3)
    case 2: ball = BallNode(imageNamed: "minusFive", speed: 0.008, value: -5)
    // etc.
    }

    ball.name = "BALL"
    ball.size = CGSize(width: 100, height: 100)
    ball.physicsBody?.linearDamping = 0

    // ...UNRELATED BALL STUFF...

    self.addChild(ball)
}

Then, to handle a touch, use the touched ball's value to update the score:

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touch in touches {
        let location = touch.location(in: self)
        if let ball = self.nodes(at: location).flatMap({ $0 as? BallNode }).first {
            currentScore += ball.value
            ball.removeFromParent()
        }
    }
}