Swift中performSelector的替代品? [英] Alternative to performSelector in Swift?

问题描述

performSelector系列方法在Swift中不可用.那么，如何在@objc对象上调用方法，而要在运行时选择要调用的方法，而在编译时却不知道该方法呢? NSInvocation显然在Swift中也不可用.

The performSelector family of methods are not available in Swift. So how can you call a method on an @objc object, where the method to be called is chosen at runtime, and not known at compile time? NSInvocation is apparently also not available in Swift.

我知道在Swift中，您可以将任何方法(对于此方法，可见@objc方法声明)发送给类型AnyObject，类似于Objective-C中的id.但是，这仍然需要您在编译时对方法名称进行硬编码.有没有办法在运行时动态选择它?

I know that in Swift, you can send any method (for which there is an @objc method declaration visible) to the type AnyObject, similar to id in Objective-C. However, that still requires you to hard-code the method name at compile-time. Is there a way to dynamically choose it at runtime?

推荐答案

使用闭包

class A {
    var selectorClosure: (() -> Void)?

    func invoke() {
        self.selectorClosure?()
    }
}

var a = A()
a.selectorClosure = { println("Selector called") }
a.invoke()

请注意，这并不是什么新鲜事物，即使在Obj-C中，新的API还是比performSelector更喜欢使用块(比较UIAlertView，它使用respondsToSelector:和performSelector:来调用委托方法，而新的UIAlertController ).

Note that this is nothing new, even in Obj-C the new APIs prefer using blocks over performSelector (compare UIAlertView which uses respondsToSelector: and performSelector: to call delegate methods, with the new UIAlertController).

使用performSelector:始终是不安全的，并且不能与ARC配合使用(因此performSelector:的ARC警告).

Using performSelector: is always unsafe and doesn't play well with ARC (hence the ARC warnings for performSelector:).

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