如何在Swift中的图像之间切换？

Question

我的屏幕中央有一辆车的图像。所以当我按下屏幕，我希望它从汽车变成平面图像，当我放开屏幕时，我希望它回到汽车图像。我现在的代码不断地重复生成图像，它们不会在这两个图像之间切换。下面是我的代码：

func addCar() {

    let redCar = SKSpriteNode(imageNamed: "redC")
    redCar.position = CGPointMake(self.size.width / 2, self.size.height / 7)
    redCar.zPosition = 42
    addChild(redCar)



    redCar.physicsBody = SKPhysicsBody(circleOfRadius: 20)
    redCar.physicsBody?.allowsRotation = false
    redCar.physicsBody?.affectedByGravity = false
    redCar.physicsBody?.contactTestBitMask = RedCategory | RedCarCategory
    redCar.physicsBody?.categoryBitMask = RedCarCategory
    redCar.physicsBody?.collisionBitMask = RedCarCategory
}



func addBluePlane() {

    let bluePlane = SKSpriteNode(imageNamed: "blueC")

    bluePlane.position = CGPointMake(self.size.width / 2, self.size.height / 7)
    bluePlane.zPosition = 43
    addChild(bluePlane)

    bluePlane.physicsBody = SKPhysicsBody(circleOfRadius: 20)
    bluePlane.physicsBody?.allowsRotation = false
    bluePlane.physicsBody?.affectedByGravity = false
    bluePlane.physicsBody?.contactTestBitMask = GreenCategory | BluePlaneCategory
    bluePlane.physicsBody?.categoryBitMask = BluePlaneCategory
    bluePlane.physicsBody?.collisionBitMask = BluePlaneCategory
}

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
   /* Called when a touch begins */

    for touch in touches {
        if let touch = touches.first {
            let location = touch.locationInNode(self)
            let node = self.nodeAtPoint(location)

            addCar()
        }
    }
}


override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?)      
{

      addBluePlane()

}

Answer 1

我没有任何具体的SpriteKit经验，但似乎您正在一次又一次地创建和添加节点。应该将redCar声明为实例变量，而不是类中的局部变量。bluePlane也是如此。

class YourClass {
    let redCar = SKSpriteNode(imageNamed: "redC")
    let bluePlane = SKSpriteNode(imageNamed: "blueC")

    func addCar() {
        bluePlane.removeFromParent()
        addChild(redCar)
        //rest goes here. dont create another redCar object
        //.......
    }

    func addBluePlane() {
        redCar.removeFromParent()
        addChild(bluePlane)
        //rest goes here. dont create another bluePlane object
        //.......
    }
}

Answer 2

开始工作了！我就是这样做的：

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
   /* Called when a touch begins */



        if let touch = touches.first {
            let location = touch.locationInNode(self)
            let node = self.nodeAtPoint(location)



            addCar()
            bluePlane.removeFromParent()




    }
}




override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {

    addBluePlane()
    redCar.removeFromParent()


}