如何在Swift中注册UndoManager? [英] How do I register UndoManager in Swift?

问题描述

如何在Swift中使用UndoManager(以前是NSUndoManager)?

How do I use UndoManager (previously NSUndoManager) in Swift?

这是我尝试复制的一个Objective-C示例:

Here's an Objective-C example I've tried to replicate:

[[undoManager prepareWithInvocationTarget:self] myArgumentlessMethod];

但是，Swift似乎没有NSInvocation，这(似乎)意味着我无法在未实现的undoManager上调用方法.

Swift, however, seems to not have NSInvocation, which (seemingly) means I can't call methods on the undoManager that it doesn't implement.

我已经在Swift中尝试了基于对象的版本，但是它似乎使我的Playground崩溃了:

I've tried the object-based version in Swift, but it seems to crash my Playground:

undoManager.registerUndoWithTarget(self, selector: Selector("myMethod"), object: nil)

尽管它似乎崩溃了，即使我的对象接受了AnyObject?

However it seems to crash, even with my object accepts an argument of type AnyObject?

在Swift中执行此操作的最佳方法是什么?有没有一种方法可以避免通过基于对象的注册发送不必要的对象?

What's the best way to do this in Swift? Is there a way to avoid sending an unnecessary object with the object-based registration?

推荐答案

我在一个Playground中尝试过，并且运行正常:

I tried this in a Playground and it works flawlessly:

class UndoResponder: NSObject {
    @objc func myMethod() {
        print("Undone")
    }
}

var undoResponder = UndoResponder()
var undoManager = UndoManager()
undoManager.registerUndo(withTarget: undoResponder, selector: #selector(UndoResponder.myMethod), object: nil)
undoManager.undo()

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