如何在一段时间后重置计时器? [英] How can I reset the timer after a certain duration?

问题描述

我在下面的代码中设置了一个计时器.如何在每次达到给定的持续时间(例如 7 秒)时重置计时器?

I have set a timer in my code below. How can I make the timer reset every time it reaches a given duration say, 7 seconds?

class SpriteGroup    {
var sprites : [Sprite]
var isVisible : Bool
var startTime: TimeInterval = 0.0
var currentTime: TimeInterval = 0.0


init(sprites : [Sprite], isVisible: Bool, pos: CGPoint) {
    self.sprites = sprites
          ...       
    startTime = Date.timeIntervalSinceReferenceDate
    Timer.scheduledTimer(timeInterval: 1,
                         target: self,
                         selector: #selector(self.advanceTimer(timer:)),
                         userInfo: nil,
                         repeats: true)
}

   func advanceTimer(timer: Timer)
{
    currentTime = Date.timeIntervalSinceReferenceDate - startTime
}

推荐答案

我可能会这样做

我添加了一个 Clouds 的子类来向您展示它们的 Timer 如何受到场景更新的影响，它只是以均匀的速度在场景中滚动云，而不管设备性能如何

I've added a subclass of Clouds to show you how their Timer is affected by the update of the Scene, it just scrolls clouds across the scene at at an even pace regardless of device performance

private var lastUpdateTime: TimeInterval = 0.0

override func update(_ currentTime: TimeInterval) {

    //check if game is actually playing, don't want to update time if game is paused
    if lastUpdateTime == 0 || gameState != .playing {

        lastUpdateTime = currentTime
        return
    }

    let delta = currentTime - lastUpdateTime

    if delta > 7 {
        //this has now been 7 seconds so do something here
    }

    //reset timer
    lastUpdateTime = currentTime

    enumerateChildNodes(withName: "cloud*", using:  { cloud, stop in
        if let cloud = cloud as? Cloud {
            cloud.update(delta: delta)
        }
    })
}

class Cloud: SKSpriteNode {

    private var minY: CGFloat = 0
    private var maxY: CGFloat = 0
    private var cloudWidth: CGFloat = 0

    private override init(texture: SKTexture?, color: UIColor, size: CGSize) {
        super.init(texture: texture, color: color, size: size)
    }

    convenience init() {

        let texture = SKTexture(image: #imageLiteral(resourceName: "cloud1"))
        self.init(texture: texture, color: SKColor.white, size: texture.size())
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    func setup(type: CloudType) {

        texture = type.texture
        size = (texture?.size())!
        setScale(2.0)

        var midHeight = gameModel.gameHeight / 2
        if let anchorY = (self.parent as? SKScene)?.anchorPoint.y {
            midHeight = gameModel.gameHeight * anchorY
        }

        self.minY = gameModel.gameHeight * 0.3 - midHeight
        self.maxY = gameModel.gameHeight * 0.9 - midHeight
        cloudWidth = self.size.width

        let randomY = RandomFloatBetween(min: minY, max: maxY)
        self.position = CGPoint(x: gameModel.gameWidth / 2 + cloudWidth, y: randomY)
    }

    func update(delta: TimeInterval) {

        let speedX = CGFloat(delta) * 90
        self.position.x -= speedX

        if self.position.x <= 0 - (gameModel.gameWidth / 2 + cloudWidth) {
            resetCloud()
        }
    }

    private func resetCloud() {

        self.position.x = gameModel.gameWidth / 2 + cloudWidth
        self.position.y = RandomFloatBetween(min: minY, max: maxY)
        enabled = false
        run(.wait(forDuration: 5, withRange: 3), completion: { self.enabled = true })
    }
}

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