方法与先前的声明与相同的Objective-C选择器发生冲突

I am working on iOS app which is having Obj C code as well as Swift. I am migrating my existing Objective C category to swift code. But when I override existing method in swift extension, it is not compiling. Swift extension is working well for new methods but not for overriding existing methods.

我正在开发iOS应用，它有Obj C代码和Swift代码。我正在将现有的Objective - C类别迁移到swift代码中。但是当我重写swift扩展中的现有方法时，它不是编译。Swift扩展适用于新方法，但不适用于覆盖现有方法。

Code:

代码:

extension UIViewController {


   public override func shouldAutorotate() -> Bool {
        return false
    }

    public override func supportedInterfaceOrientations() -> UIInterfaceOrientationMask {
        return UIInterfaceOrientationMask.Portrait
    }


}

Error:

错误:

 Method 'shouldAutorotate()' with Objective-C selector 'shouldAutorotate' conflicts with previous declaration with the same Objective-C selector

 Method does not override any method from its superclass

 Method 'supportedInterfaceOrientations()' with Objective-C selector 'supportedInterfaceOrientations' conflicts with previous declaration with the same Objective-C selector

Here, Am I missing anything?

这里，我漏掉了什么吗?

I am using Xcode 7.3.1 and Swift 2.x

我使用的是Xcode 7.3.1和Swift 2.x

EDIT:

编辑:

From below Answers, I got to know that We cant change behaviour of existing method of class at runtime in Swift extension like in Objective C Categories. Here I should make a base class which will override method and I should use all my ViewControllers as child classes from new base class as parent.

从下面的答案中，我了解到我们不能像Objective C类那样在快速扩展的运行时改变现有类方法的行为。在这里，我应该创建一个基类，它将覆盖方法，我应该将所有的ViewControllers作为父类从新的基类中使用。

But in my case, I want to change behaviour of all "shouldAutorotate" methods including 3rd party frameworks UIViewController. In above case I cant force all third party frameworks UIviewControllers to become subclass of my base class. In Objective C i could achieve this.

但在我的例子中，我想改变所有"shouldAutorotate"方法的行为包括第三方框架UIViewController。在上面的例子中，我不能强迫所有第三方框架UIviewControllers变成我基类的子类。在目标C中，我可以做到这一点。

1 个解决方案

#1

Swift extensions aren't to be used to override methods declared in the class they're extending – especially for Objective-C classes, that's very much like providing two definitions of the same method in the same class. Imagine seeing a class that looked like:

Swift扩展不能用于覆盖它们正在扩展的类中声明的方法——特别是对于Objective-C类，这很像在同一个类中提供相同方法的两个定义。想象一下，看到一门课

class UIViewController : UIResponder {
    public func shouldAutorotate() -> Bool {
        return true
    }
    public func shouldAutorotate() -> Bool {
        return false
    }
}

Which one wins? That's the conflict you're being warned about.

哪一个赢了?这就是你被警告的冲突。

If you need to override methods for a view controller of yours, you'll need to do that in a subclass, not an extension.

如果需要重写视图控制器的方法，则需要在子类中完成，而不是在扩展中。

Ninja edit: this may have been possible to do in Objective-C, but was a programming error there. If a category duplicates a method from a main class, which definition gets used is undefined. See this SO post and the backing Apple documentation.

Ninja编辑:这在Objective-C中可能实现，但这是一个编程错误。如果一个类别复制了一个来自主类的方法，则使用哪个定义是未定义的。请参阅SO post和支持苹果的文档。

#1

class UIViewController : UIResponder {
    public func shouldAutorotate() -> Bool {
        return true
    }
    public func shouldAutorotate() -> Bool {
        return false
    }
}