xcode - 使用图像作为 Sprite 角色

Question

所以我正在开发一款游戏，并在我的 swift 2 spritekit 游戏中使用一个球。我有一个 make ball 函数，在游戏场景中，当调用该方法时，我不断收到此错误:“无法分配 SKShapeNode”来输入 Ball!我不知道如何修复，并且是 swift 新手。谢谢!

// ----- GameScene.Swift ----
class GameScene: SKScene, GameDelegate, SKPhysicsContactDelegate {
   // ball part one
   var ball: Ball!
   let ballSpeedX = CGFloat(500)
}

 override func didMoveToView(view: SKView) {
    // ball
    ball = Ball.make() // error!!!
    ball.position.x = CGRectGetMidX(self.frame)
    ball.position.y = CGRectGetMidY(self.frame)
    ball.physicsBody!.categoryBitMask = CollideType.Ball.toMask()
    ball.physicsBody!.collisionBitMask = CollideType.toMask([.Scene, .Ceil, .Floor]) | boards.usedCollideMasks
    ball.physicsBody!.contactTestBitMask = CollideType.toMask([.Scene, .Ceil, .Floor]) | boards.usedCollideMasks
    ball.hidden = true
    self.addChild(ball)
 }

然后这是 ball.swift，其中 make() 是//Ball。 swift

//imports...

class Ball: SKShapeNode {

  var speedXFirst = CGFloat(0)
var speedXSecond = CGFloat(0)
var lastFloor = -1

var xSpeed: CGFloat {
    get {
        return speedXFirst + speedXSecond
    }
}

var lastBoardNumber = 0

private override init() {
    super.init()
}

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

static func make()-> SKShapeNode {

    let textureBall : SKTexture! = SKTexture(imageNamed:"colorBall.png")
    let ballSize: CGSize = textureBall.size()
    var ball = SKShapeNode.init(circleOfRadius: ballSize.width/2)
    ball.fillTexture = textureBall
    ball.strokeColor = UIColor.clearColor()
    ball.name = "ball"
    ball.zPosition = 1
    ball.fillColor = UIColor.redColor() // use the color you want
    return ball
 }

 func freezeX() {
    self.speedXFirst = 0
    self.speedXSecond = 0
}
}

Answer 1

要成功执行 ball = Ball.make()，make() 方法的返回类型需要为 Ball，而不是 SKSpriteNode.

要从 make() 返回 Ball 值，您需要创建 Ball 的实例，而不是 SKSpriteNode.

static func make() -> Ball {  //the return type of `make()` method needs to be `Ball`

    let textureBall : SKTexture! = SKTexture(imageNamed:"colorBall.png")
    let ballSize: CGSize = textureBall.size()
    let ball = Ball(circleOfRadius: ballSize.width/2) //you need to create an instance of `Ball`
    ball.fillTexture = textureBall
    ball.strokeColor = UIColor.clearColor()
    ball.name = "ball"
    ball.zPosition = 1
    ball.fillColor = UIColor.redColor()
    return ball
}