for循环CGFloat中的错误 [英] Error in for loop CGFloat
本文介绍了for循环CGFloat中的错误的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我将一个项目从 Swift 2 转换为 Swift 3,现在我收到以下行中的错误:
I converted a project from Swift 2 to Swift 3 and now I get an error in the following line:
for i:CGFloat in 0 ..< 2.0 + self.frame.size.width / ( skyTexture.size().width * 2.0 ) += 1 {
其中说:变异操作符的左边是不可变的'..<'返回不可变值
let skyTexture = SKTexture(imageNamed: "sky")
skyTexture.filteringMode = .nearest
let moveSkySprite = SKAction.moveBy(x: -skyTexture.size().width * 2.0, y: 0, duration: TimeInterval(0.1 * skyTexture.size().width * 2.0))
let resetSkySprite = SKAction.moveBy(x: skyTexture.size().width * 2.0, y: 0, duration: 0.0)
let moveSkySpritesForever = SKAction.repeatForever(SKAction.sequence([moveSkySprite,resetSkySprite]))
for i:CGFloat in 0 ..< 2.0 + self.frame.size.width / ( skyTexture.size().width * 2.0 ) += 1 {
let sprite = SKSpriteNode(texture: skyTexture)
sprite.setScale(2.0)
sprite.zPosition = -20
sprite.position = CGPoint(x: i * sprite.size.width, y: sprite.size.height / 2.0 + groundTexture.size().height * 2.0)
sprite.run(moveSkySpritesForever)
moving.addChild(sprite)
}
推荐答案
本质上你想要的仍然是一个循环,整数值递增 1.所以你可以只计算最后一个 int 值并为每个循环使用一个简单的:
In essence what you want is still a loop through integer values incremented by 1. So you can just calculate the last int value and use a simple for each loop:
for i in 0..<Int(self.frame.size.width / ( skyTexture.size().width * 2.0 )) + 2 {
//do your stuff here
sprite.position = CGPoint(x: CGFloat(i) * sprite.size.width, y: sprite.size.height / 2.0 + groundTexture.size().height * 2.0)
}
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