Swift 约束错误

Question

我正在尝试为使用 UIPanGestureRecognizer 移动的按钮创建一些约束

button.setTranslatesAutoresizingMaskIntoConstraints(false)

let line = ("\(p.x % snapX)")
let column = ("\(p.x % snapY)")

let constraint2 = NSLayoutConstraint(item: button, attribute: .CenterX, relatedBy: .Equal, toItem: view, attribute: .CenterX, multiplier: 1, constant: CGFloat(line))

let constraint3 = NSLayoutConstraint(item: button, attribute: .CenterY, relatedBy: .Equal, toItem: view, attribute: .CenterY, multiplier: 1, constant: CGFloat(column))

view.addConstraints([constraint2,constraint3])

但我有一个“找不到成员 'CenterX' 错误

P.s。行和列可能取值 27.6666564941406 和 0.666656494140625

Answer 1

看起来编译器试图在错误的枚举类型上查找 CenterX。尝试使用完整的枚举定义：

NSLayoutAttribute.CenterX

和

NSLayoutAttribute.CenterY

Swift 约束错误

Swift error on Constraints

swift

ios8