Create a .h file from NewFile -> Source -> header file Then save the name of file Your_Target_Name-Bridging-Header.h People here gets common mistake by taking their project name but it should be the Project's Target's name if in case both are different, generally they are same. Then in build settings search for Objective-C Bridging Header flag and put the address of your newly created bridging file, you can do it right click on the file -> show in finder -> drag the file in the text area then the address will be populated. Using #import Your_Objective-C_file.h In the swift file you can access the ObjC file but in swift language only.

参见Apple的使用Cocoa和Objective-C的Swift指南。本指南涵盖了如何使用Swift中的Objective-C和C代码，反之亦然，并对如何转换项目或在现有项目中混合和匹配Objective-C/C和Swift部分提出了建议。

编译器自动生成调用C函数和Objective-C方法的Swift语法。如文档所示，这个Objective-C:

UITableView *myTableView = [[UITableView alloc] initWithFrame:CGRectZero style:UITableViewStyleGrouped];

变成了这样的Swift代码:

let myTableView: UITableView = UITableView(frame: CGRectZero, style: .Grouped)

Xcode也可以在运行中进行这种转换——你可以在编辑Swift文件时使用Open quick，并输入Objective-C类名，它会带你到Swift化的类头。(你也可以通过cmd点击Swift文件中的API符号来获得。)iOS 8和OS X v10.10 (Yosemite)开发者库中的所有API参考文档在Objective-C和Swift表单(例如UIView)中都是可见的。

给那些试图将Objective-C库添加到Swift的人一个提示:你应该在构建设置中添加- objc ->链接->其他链接器标志。

引用自文档:

Any Objective-C framework (or C library) that’s accessible as a module can be imported directly into Swift. This includes all of the Objective-C system frameworks—such as Foundation, UIKit, and SpriteKit—as well as common C libraries supplied with the system. For example, to import Foundation, simply add this import statement to the top of the Swift file you’re working in: import Foundation This import makes all of the Foundation APIs—including NSDate, NSURL, NSMutableData, and all of their methods, properties, and categories—directly available in Swift.

在Xcode 10.1中的Swift 4.2.1项目中，您可以轻松地添加Objective-C文件。按照以下步骤将Objective-C文件连接到Swift项目。

Step_01:使用Swift语言创建新的Xcode项目:

文件>新建>项目> objc。

在Swift项目中添加新的Objective-C文件:

File >新建>文件…> macOS > Objective-C文件。

Step_03:如果你第一次添加一个新的Objective-C文件到Swift项目中，Xcode会问你:

你想配置一个Objective-C桥接头吗?

Step_04:选择选项:

创建桥接头。

Step_05:将生成一个对应的文件，文件的名称如下:

Objc-Bridging-Header.h。

Step_06:现在，你需要在桥标头中设置桥文件路径。在项目导航器中单击名称为objc的项目，然后选择:

> Objective-C桥接头> objc桥接头。h

将Objc-Bridging-Header.h拖放到该框中生成文件路径。

打开你的Objc-Bridging-Header.h文件，并导入你想要在Swift文件中使用的Objective-C文件。

#import "SpecialObjcFile.m"

下面是SpecialObjcFile.m的内容:

#import <Foundation/Foundation.h>

@interface Person: NSObject {
@public
    bool busy;
}
@property
    bool busy;
@end

现在在你的Swift文件中，你可以使用一个Objective-C类:

override func viewDidLoad() {
    super.viewDidLoad()
    let myObjcContent = Person()
    print(myObjcContent.busy)
}

Create a .h file from NewFile -> Source -> header file Then save the name of file Your_Target_Name-Bridging-Header.h People here gets common mistake by taking their project name but it should be the Project's Target's name if in case both are different, generally they are same. Then in build settings search for Objective-C Bridging Header flag and put the address of your newly created bridging file, you can do it right click on the file -> show in finder -> drag the file in the text area then the address will be populated. Using #import Your_Objective-C_file.h In the swift file you can access the ObjC file but in swift language only.