ios - for 循环错误

Question

我正在用 SpriteKit 制作一个游戏，我写这个是为了制作一个移动的背景:

        let spaceMovement = SKAction.moveBy(CGVector(dx:0, dy:-bg1.frame.size.height), duration: NSTimeInterval(0.4 * bg1.frame.size.height))
        let resetSpace = SKAction.moveBy(CGVector(dx:0, dy:bg1.frame.size.height), duration: 0.0)
        let repeatSpaceMovement = SKAction.repeatActionForever(SKAction.sequence([spaceMovement, resetSpace]))

        for var i:CGFloat = 0; i < self.frame.size.height / (bg1.size.height); i++
        {
            let sprite = self.bg1;
            sprite.zPosition = -20
            sprite.position = CGPointMake(sprite.size.width/2, i * sprite.size.height)
            sprite.runAction(repeatSpaceMovement)
            self.addChild(sprite)

        }

但它给了我这个错误:

libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb) 

Answer 1

我认为您缺少一个 .frame，所以您最终除以 0？也许你的意思是:

for var i:CGFloat = 0; i < self.frame.size.height / (bg1.frame.size.height); i++

另外，不要使用 C++ 风格的循环。他们要走了，他们很丑。这个怎么样？它的行为应该相同。

for i in (0..<self.frame.size.height / bg1.frame.size.height) {
    ...
}