objective-c代码可以在类上调用swift扩展吗?

I searched some posts, I think I cannot write an extension under swift, and call it from Objective-C code, right ?

我搜索了一些帖子，我认为我不能在swift下写扩展名，并从Objective-C代码中调用它，对吧?

@objc like attributes only support methods, class, protocols ?

@objc属性只支持方法、类、协议?

4 个解决方案

#1

You can write a Swift extension and use it in ObjectiveC code. Tested with XCode 6.1.1.

您可以编写一个快速扩展并在ObjectiveC代码中使用它。与XCode但是测试。

All you need to do is:

你所需要做的就是:

create your extension in Swift (no @objc annotation)

在Swift中创建扩展(没有@objc注释)
import "ProjectTarget-Swift.h" in your ObjectiveC class (where "ProjectTarget" represents the XCode target the Swift extension is associated with)

导入“ProjectTarget-Swift。在您的ObjectiveC类中的h(其中“ProjectTarget”表示与Swift扩展相关联的XCode目标)
call the methods from the Swift extension

调用来自Swift扩展的方法

#2

This solution works for Swift 2.2 and Swift 3. Note that only extensions for classes (not for structs or enums) will be accessible from Objective-C.

该解决方案适用于Swift 2.2和Swift 3。注意，只有类的扩展(不是结构或枚举)可以从Objective-C中访问。

import UIKit

extension UIColor {

    //Custom colours
    class func otheEventColor() -> UIColor {
        return UIColor(red:0.525, green:0.49, blue:0.929, alpha:1)
    }
}

Then #import "ProductModuleName-Swift.h" in your ObjC file.

然后ProductModuleName-Swift #进口”。h"在你的ObjC文件中。

#3

As covered in the other answers, importing the generated Swift header works in most cases.

如其他答案所述，导入生成的Swift标头在大多数情况下都有效。

An exception to this is when the category is defined on a bridged type (i.e. the extension is defined on String and not NSString). These categories will not automatically be bridged to their Objective-C counterparts. To get around this, you'll either need to use the Objective-C type (and cast the return value in your Swift code with as String) or define an extension for both the Swift and Objective-C types.

一个例外是当类别定义为桥接类型时(即扩展定义为字符串而非NSString)。这些类别不会自动地连接到它们的Objective-C对应项。要解决这个问题，您需要使用Objective-C类型(并将Swift代码中的返回值转换为字符串)，或者为Swift和Objective-C类型定义扩展。

#4

I found out that in Swift 4.0 I had to add @objc in front of my extension keyword in order for the Swift extension methods to become visible by an instance of the Objc class I was extending.

我发现在Swift 4.0中，我必须在我的extension关键字前面添加@objc，以便Swift扩展方法被我正在扩展的Objc类的实例可见。

In short:

简而言之:

File configuration setup:

文件配置设置:

CustomClass.h
CustomClass.m
CustomClassExtension.swift

In CustomClassExtension:

在CustomClassExtension:

@objc extension CustomClass
{
    func method1() 
    {
        ...
    }
}

In my AppDelegate.m:

在我AppDelegate.m:

self.customClass = [[CustomClass alloc] init];
[self.customClass method1];

#1