二进制运算符'.. <'不能应用于'Int'和'CGFloat'类型的操作数

Question

我正在尝试创建一个for循环,但似乎无法理解如何摆脱这个错误

我的代码:

for i:CGFloat in 0 ..< 2 + self.frame.size.width / (movingGroundTexture.size().width) { 
        let sprite = SKSpriteNode(texture: movingGroundTexture)
        sprite.zPosition = 0
        sprite.anchorPoint = CGPointMake(0, 0)
        sprite.position = CGPointMake(i * sprite.size.width, 0)
        addChild(sprite)
    }

错误for在线self.frame.size.width和(movingGroundTexture.aize().width)

Answer 1

您不能使用浮点类型创建CountableRange(或CountableClosedRange).

您要么将您转换2 + self.frame.size.width / movingGroundTexture.size().width为Int:

for i in 0 ..< Int(2 + self.frame.size.width / movingGroundTexture.size().width) { 
    // i is an Int      
}

或者你想使用stride(Swift 2语法):

for i in CGFloat(0).stride(to: 2 + self.frame.size.width / movingGroundTexture.size().width, by: 1) { 
    // i is a CGFloat   
}

Swift 3语法:

for i in stride(from: 0, to: 2 + self.frame.size.width / movingGroundTexture.size().width, by: 1) {
    // i is a CGFloat
}

取决于您是否需要浮点精度.请注意,如果您的上限是非整数值,则stride版本将比范围运算符版本再迭代一次,因为Int(...)忽略小数组件.

Answer 2

您必须将范围的右侧转换为整数类型,例如Int或UInt:

for i in 0 ..< Int(2 + self.frame.size.width / (movingGroundTexture.size().width)) {
    ...
}