swift有类级静态变量吗？ [英] Does swift have class level static variables?

问题描述

如何在类范围中声明静态常量？例如

How to declare static constant in class scope? such as

class let Constant: Double = 3.1415926
// I know that in class we use class modifier instead of static.

推荐答案

的Swift 1.2：

Swift supports static type properties, including on classes, as of Swift 1.2:

class MyClass {
    static let pi = 3.1415926
}

如果你需要一个类变量在子类中是可覆盖的，你需要使用一个计算的类属性：

If you need to have a class variable that is overridable in a subclass, you'll need to use a computed class property:

class MyClass {
    class var pi: Double { return 3.1415926 }
}

class IndianaClass : MyClass {
    override class var pi: Double { return 4 / (5 / 4) }
}

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