我正在使用Swift在SpriteKit中制作游戏 . 我不能为我的生活弄清楚为什么我的节点不会碰撞并从屏幕反弹，这是SKSpriteNode的默认行为 .

这是我在三个不同文件中的所有代码：

GameViewController：

override func viewDidLoad() {
    super.viewDidLoad()

    let skView = view as! SKView
    skView.showsFPS = true
    skView.showsNodeCount = true

    let battleScene = CSLevel()
    battleScene.size = view.frame.size
    battleScene.scaleMode = .AspectFill

    skView.presentScene(battleScene)
}

CSLevel：

//sorry here's the real code     
class CSLevel: SKScene, SKPhysicsContactDelegate {

    var myWorld: SKNode!
    var leader: CSCharacter?

    override init(size: CGSize) {
        super.init(size: size)

        setUpScene()
        setUpCharacters()
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func didMoveToView(view: SKView) {
        super.didMoveToView(view)


    }

    func setUpScene() {
        //Take care of setting up the world and bring in property list

        self.anchorPoint = CGPoint(x: 0.5, y: 0.5) //0,0 to 1,1

        myWorld = SKNode()
        self.addChild(myWorld)

        let map = SKSpriteNode(imageNamed: "map")
        map.position = CGPoint(x: 0, y: 0)

        myWorld.addChild(map)

        myWorld.xScale = 1
        myWorld.yScale = 1

        //Setup physics
        self.physicsWorld.gravity = CGVector(dx: 0, dy: -1)
        self.physicsWorld.contactDelegate = self

        myWorld.physicsBody = SKPhysicsBody(edgeLoopFromRect: screenFrame)
        myWorld.physicsBody?.categoryBitMask = wallCategory
    }

    func setUpCharacters() {
        leader = CSCharacter()
        myWorld.addChild(leader!)
    }

    override func update(currentTime: NSTimeInterval) {

    }

    func didBeginContact(contact: SKPhysicsContact) {
        let firstBody = contact.bodyA
        let secondBody = contact.bodyB

        if firstBody.categoryBitMask == wallCategory || secondBody.categoryBitMask == wallCategory {

        }
    }
}

CSCharacter：

class CSCharacter: SKNode {

    var character: SKSpriteNode! //this will be the actual image you see of the character

    override init() {
        super.init()

        character = SKSpriteNode(imageNamed: "character")
        self.addChild(character)

        self.physicsBody = SKPhysicsBody(circleOfRadius: character.frame.size.width / 2)
        self.physicsBody?.dynamic = true
        self.physicsBody?.restitution = 5
        self.physicsBody?.allowsRotation = true

        self.xScale = 2
        self.yScale = 2

        self.physicsBody?.categoryBitMask = playerCategory
        self.physicsBody?.collisionBitMask = wallCategory
        self.physicsBody?.contactTestBitMask = wallCategory
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}

这是一个错误还是什么？运行Xcode beta 7.1 . 我实际上是在遵循一个教程，并且它的行为方式与该人的行为方式不同，即使我在函数中键入函数，他正在键入的内容 . 任何帮助或澄清赞赏！