Swift:变量的值是公共(public)的但仍然是本地的？

Question

我更改了一个函数中的值，并想访问同一类中另一个函数中的值。我的代码:

class person{

var fieldsWidth = CGFloat()
var xPos = CGFloat()
var yPos = CGFloat()
var player = SKSpriteNode()

func addPlayer(gameScene: GameScene, x: CGFloat, y: CGFloat){
    fieldsWidth = gameScene.screenWidth / CGFloat(hintergrund().fieldsX)
    player = SKSpriteNode(imageNamed: "player")
    player.size = CGSize(width: fieldsWidth, height: fieldsWidth)
    player.position = CGPoint(x: x, y: y)
    gameScene.addChild(player)
    xPos = x
}

func move(gameScene: GameScene, point: CGPoint, fWidth: CGFloat){
    print(xPos)
}

和游戏场景:

class GameScene: SKScene {

var screenWidth = CGFloat()
var screenHeight = CGFloat()
var touchLocation = CGFloat()
var fieldsWidth = CGFloat()
let player = person()

override func didMoveToView(view: SKView) {
    screenWidth = self.size.width
    screenHeight = self.size.height
    fieldsWidth = screenWidth / CGFloat(hintergrund().fieldsX)
    person().addPlayer(self, x: fieldsWidth/2, y: fieldsWidth/2)
}

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    /* Called when a touch begins */
    let touch =  touches.first
    var point = CGPoint()
    point = touch!.locationInNode(self)
    player.move(self, point: point, fWidth: fieldsWidth)
}

}

不知何故，xPos 的值只是在 addPlayer 中的本地值。如何正确访问 xPos 的值？希望你能帮助我。

Answer 1

以下代码在 XCode Version 7.1 (7B91b) playground 中完全按照我的预期运行

class person{

    var yPos = CGFloat()

    func function1(y: CGFloat){
        yPos = y
        print(yPos)  //Value of yPos is 31.25; correct!
    }

    func function2(){
        print(yPos)  //Value of yPos is 0.0; wrong!??
    }
}

let foo = person()
foo.function1(31.25)
foo.function2() //Outputs 31.25