Swift中的私人二手“set()”

这是点示例介绍了由 apple提供的pint结构setter getter如何才能使setter私有化

struct Point {
    var x = 0.0,y = 0.0
}
struct Size {
    var width = 0.0,height = 0.0
}
struct Rect {
    var origin = Point()
    var size = Size()
    var center: Point {
        get {
            let centerX = origin.x + (size.width / 2)
            let centerY = origin.y + (size.height / 2)
            return Point(x: centerX,y: centerY)
        }
        set(newCenter) {
            origin.x = newCenter.x - (size.width / 2)
            origin.y = newCenter.y - (size.height / 2)
        }
    }
}

您可以按如下方式细化struct Rect.这将允许您只获得中心但不设置它.

struct Rect {

    var center:Point {
        let centerX = origin.x + (size.width / 2)
        let centerY = origin.y + (size.height / 2)
        return Point(x: centerX,y: centerY)
    }

    var origin = Point()
    var size = Size()
}