在Swift中使用 - observeValueForKeyPath：ofObject：change：context： [英] Using - observeValueForKeyPath:ofObject:change:context: in Swift 3

问题描述

我试图将一个Swift 2.2项目转换为Swift 3，我得到以下错误：

I'm trying to convert a Swift 2.2 project to Swift 3, and I'm getting the following error:

Method 'observeValue(forKeyPath:ofObject:change:context:)' with Objective-C selector 'observeValueForKeyPath:ofObject:change:context:' conflicts with method 'observeValue(forKeyPath:of:change:context:)' from superclass 'NSObject' with the same Objective-C selector" for the function call

上使用相同的Objective-C选择器。 p>

On my function whose signature is:

func observeValue(forKeyPath keyPath: String?, ofObject: Any?, change: [String : Any]?, context: UnsafeMutableRawPointer?)."

我已阅读Swift 3迁移指南网站上的建议：

I have read the advice on the Swift 3 Migration Guide web site:

解决方法：在原始Objective-C选择器内部实现可选需求之前添加一个@objc（objectiveC：name :)属性。

"Workaround: Add an @objc(objectiveC:name:) attribute before the implementation of the optional requirement with the original Objective-C selector inside."

但是我不清楚这是真的应该在源文件中应用，我迄今为止没有尝试过的工作成功

But it isn't clear to me how this is actually supposed to be applied in a source file, and nothing I have tried so far has worked successfully.

任何人都可以解释如何正确设置此项。

Can anyone explain how to set this up properly?

推荐答案

刚开始键入 observeValueFor ... 和 Xcode 会建议您有效的自动完成。

Just start typing observeValueFor... and Xcode will suggest you a valid autocompletion for that. Choose it, and you should be good to go.

您的函数应该看起来像这样：

Your function then should look something like this:

override func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutablePointer<Void>) 

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