从Objective C中的Swift类继承 [英] Inherit from a Swift class in Objective C

问题描述

我在Xcode 7项目中成功地混合和匹配Obj-C和Swift。但是，我似乎无法弄清楚在Objective C类中如何从Swift类继承（是的，我知道将Swift类声明为 @objc 为了能见度）。在这种情况下，所需的Swift超类 MySwiftViewController 是 UIViewController 的子类。现在，在Obj-C中，我直接从 UIViewController 继承，并且无法访问我在 MySwiftViewController中添加的功能。

I'm successfully mixing and matching Obj-C and Swift in an Xcode 7 project. However, I can't seem to figure out how, in an Objective C class, to inherit from a Swift class (and yes I know about declaring that Swift class as @objc for visibility). In this case the desired Swift superclass MySwiftViewController is a subclass of UIViewController. For now, in Obj-C, I'm inheriting directly from UIViewController and not gaining access to the capabilities I added in MySwiftViewController.

以下是我的理解：

- 将Obj-C类声明为继承自一些东西，必须在'：'之后的.h文件中：

-- To declare an Obj-C class as inheriting from something, that must be in the .h file after the ':':

#import <UIKit/UIKit.h>
@interface RootViewController : UIViewController <UITableViewDataSource, UITableViewDelegate>
@end

- 要使Swift类可见，那就是 #import ed：

-- To make Swift classes visible, that is #imported:

#import "MyProject-Swift.h"

但是，您无法将Swift自动生成的桥接头导入Obj-C .h 文件。您也无法使用 @class 向前声明一个不透明的超类。那么，这是可能的吗？

However, you cannot import the Swift auto-generated bridging header into the Obj-C .h file. You also cannot forward-declare an opaque superclass with @class. So, is this possible and how?

推荐答案

不幸的是，不可能在Objective-C中继承Swift类。直接来自文档：

Unfortunately, it's not possible to subclass a Swift class in Objective-C. Straight from the docs:

你不能在Objective-C中继承Swift类。

You cannot subclass a Swift class in Objective-C.

请参阅Apple的互操作性指南，了解有关使用Objective-C可以访问和不能访问的内容的更多详细信息。

See Apple's guide on interoperability for more details on what you can and cannot access with Objective-C.

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