如何扩展多个类的Swift [英] How to make extension for multiple classes Swift

问题描述

我有一个扩展名:

extension UILabel {
    func animateHidden(flag: Bool) {
        self.hidden = flag
    }
}

我需要为UIImageView做相同的事情，但是我不想复制整个代码.可以扩展多个类吗?

I need to make the same one for UIImageView but I don't want to copy that whole code. Is it possible to make an extension for multiple classes?

谢谢.

推荐答案

您可以制定协议并对其进行扩展.

You could make a protocol and extend it.

类似的东西:

protocol Animations {
    func animateHidden(flag: Bool)
}

extension Animations {
    func animateHidden(flag: Bool) {
        // some code
    }
}

extension UILabel: Animations {}

extension UIImageView: Animations {}

您的方法将可用于扩展类:

Your method will be available for the extended classes:

let l = UILabel()
l.animateHidden(false)

let i = UIImageView()
i.animateHidden(false)

在注释中，您问:在这种情况下，如何在animateHidden函数中为UILabel和UIImageView调用self?".您可以通过限制扩展名来做到这一点.

In a comment, you've asked: "in this case how to call self for UILabel and UIImageView in animateHidden function?". You do that by constraining the extension.

带有where子句的示例:

extension Animations where Self: UIView {
    func animateHidden(flag: Bool) {
        self.hidden = flag
    }
}

感谢@ Knight0fDragon对where子句的出色评论.

Thanks to @Knight0fDragon for his excellent comment about the where clause.

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