#import <Foundation\/Foundation.h<\/code> to an older ObjC File) **<\/p>\nStep 1: Add Objective-C Implementation — .m<\/h3>\n
Add a .m<\/code> file to your class, and name it CustomObject.m<\/code><\/p>\nStep 2: Add Bridging Header<\/h3>\n
When adding your .m<\/code> file, you’ll likely be hit with a prompt that looks like this:<\/p>\n![\"enter](\"http:\/\/i.stack.imgur.com\/nakLZ.png\")
<\/p>\n
Click YES <\/b>!<\/p>\n
If you did not see the prompt, or accidentally deleted your bridging header, add a new .h<\/code> file to your project and name it <#YourProjectName#>-Bridging-Header.h<\/code><\/p>\nIn some situations, particularly when working with ObjC frameworks, you don’t add an Objective-C class explicitly and Xcode can’t find the linker. In this case, create your .h<\/code> file named as mentioned above, then make sure you link its path in your target’s project settings like so:<\/p>\n![\"enter](\"http:\/\/i.stack.imgur.com\/8LiwF.gif\")
<\/p>\n
Note<\/b><\/p>\n
It’s best practice to link your project using the $(SRCROOT)<\/code> macro so that if you move your project, or work on it with others using a remote repo, it will still work. $(SRCROOT)<\/code> can be thought of as the directory that contains your .xcodeproj file. It might look like this:<\/p>\n$(SRCROOT)\/Folder\/Folder\/<#YourProjectName#>-Bridging-Header.h<\/code><\/p>\nStep 3: Add Objective-C Header — .h<\/h3>\n
Add another .h<\/code> file and name it CustomObject.h<\/code><\/p>\nStep 4: Build your Objective-C Class<\/h3>\n
In CustomObject.h<\/code><\/p>\n#import <Foundation\/Foundation.h><\/span>\r\n\r\n@interface<\/span> CustomObject<\/span> :<\/span> NSObject<\/span>\r\n\r\n@property<\/span> (<\/span>strong<\/span>,<\/span> nonatomic<\/span>)<\/span> id someProperty<\/span>;<\/span>\r\n\r\n-<\/span> (<\/span>void<\/span>)<\/span> someMethod<\/span>;<\/span>\r\n\r\n@end<\/span><\/code><\/pre>\nIn CustomObject.m<\/code><\/p>\n#import \"CustomObject.h\"<\/span>\r\n\r\n@implementation<\/span> CustomObject<\/span> \r\n\r\n-<\/span> (<\/span>void<\/span>)<\/span> someMethod <\/span>{<\/span>\r\n NSLog<\/span>(@<\/span>\"SomeMethod Ran\"<\/span>);<\/span>\r\n}<\/span>\r\n\r\n@end<\/span><\/code><\/pre>\nStep 5: Add Class to Bridging-Header<\/h3>\n
In YourProject-Bridging-Header.h<\/code>:<\/p>\n#import \"CustomObject.h\"<\/span><\/code><\/pre>\nStep 6: Use your Object<\/h3>\n
In SomeSwiftFile.swift<\/code>:<\/p>\nvar instanceOfCustomObject<\/span>:<\/span> CustomObject<\/span> =<\/span> CustomObject<\/span>()<\/span>\r\ninstanceOfCustomObject<\/span>.<\/span>someProperty <\/span>=<\/span> \"Hello World\"<\/span>\r\nprintln<\/span>(<\/span>instanceOfCustomObject<\/span>.<\/span>someProperty<\/span>)<\/span>\r\ninstanceOfCustomObject<\/span>.<\/span>someMethod<\/span>()<\/span><\/code><\/pre>\nNo need to import explicitly, that’s what the bridging header is for.<\/p>\n
Using Swift Classes in Objective-C<\/h1>\nStep 1: Create New Swift Class<\/h3>\n
Add a .swift<\/code> file to your project, and name it MySwiftObject.swift<\/code><\/p>\nIn MySwiftObject.swift<\/code>:<\/p>\nimport<\/span> Foundation<\/span>\r\n\r\nclass<\/span> MySwiftObject<\/span> :<\/span> NSObject<\/span> {<\/span>\r\n\r\n var someProperty<\/span>:<\/span> AnyObject<\/span> =<\/span> \"Some Initializer Val\"<\/span>\r\n\r\n init<\/span>()<\/span> {}<\/span>\r\n\r\n func someFunction<\/span>(<\/span>someArg<\/span>:<\/span>AnyObject<\/span>)<\/span> -><\/span> String<\/span> {<\/span>\r\n var returnVal <\/span>=<\/span> \"You sent me \\(someArg)\"<\/span>\r\n return<\/span> returnVal\r\n <\/span>}<\/span>\r\n\r\n}<\/span><\/code><\/pre>\nStep 2: Import Swift Files to ObjC Class<\/h3>\n
In SomeRandomClass.m<\/code>:<\/p>\n#import \"<#YourProjectName#>-Swift.h\"<\/span><\/code><\/pre>\nThe file:<#YourProjectName#>-Swift.h<\/code> should already be created automatically in your project, even if you can not see it.<\/p>\nStep 3: Use your class<\/h3>\nMySwiftObject<\/span> *<\/span> myOb <\/span>=<\/span> [<\/span>MySwiftObject<\/span> new<\/span>];<\/span>\r\nNSLog<\/span>(@<\/span>\"MyOb.someProperty: %@\"<\/span>,<\/span> myOb<\/span>.<\/span>someProperty<\/span>);<\/span>\r\nmyOb<\/span>.<\/span>someProperty <\/span>=<\/span> @<\/span>\"Hello World\"<\/span>;<\/span>\r\nNSLog<\/span>(@<\/span>\"MyOb.someProperty: %@\"<\/span>,<\/span> myOb<\/span>.<\/span>someProperty<\/span>);<\/span>\r\nNSString<\/span> *<\/span> retString <\/span>=<\/span> [<\/span>myOb someFunction<\/span>:@<\/span>\"Arg\"<\/span>];<\/span>\r\nNSLog<\/span>(@<\/span>\"RetString: %@\"<\/span>,<\/span> retString<\/span>);<\/span><\/code><\/pre>\nNote:<\/h2>\n
1.<\/b> CodeCompletion wasn’t behaving as accurately as I’d like it to. On my system, running a quick build w\/ “cmd + r” seemed to help Swift find some of the Objc code and vice versa.<\/p>\n
2.<\/b> If you add .swift<\/code> file to an older project and get error: dyld: Library not loaded: @rpath\/libswift_stdlib_core.dylib<\/code>, try completely restarting Xcode.<\/a><\/p>\n3.<\/b> While it was originally possible to use pure Swift classes in Objective-C by using the @objc<\/code>prefix, after Swift 2.0, this is no longer possible. See edit history for original explanation. If this functionality is reenabled in future Swift versions, the answer will be updated accordingly.<\/p>\n <\/p>\n
Reference:http:\/\/stackoverflow.com\/questions\/24002369\/how-to-call-objective-c-code-from-swift<\/p>\n","protected":false},"excerpt":{"rendered":"