If you have an existing class that you’d like to use, perform Step 2 and then skip to Step 5. (For some cases, I had to add an explicit #import <Foundation/Foundation.h to an older ObjC File)

Step 1: Add Objective-C Implementation – .m

Add a .m file to your class, and name it CustomObject.m

Step 2: Add Bridging Header

When adding your .m file, you’ll likely be hit with a prompt that looks like this:

enter image description here

Click YES !

If you did not see the prompt, or accidentally deleted your bridging header, add a new .h file to your project and name it <#YourProjectName#>-Bridging-Header.h

In 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 file named as mentioned above, then make sure you link its path in your target’s project settings like so:

enter image description here

Note

It’s best practice to link your project using the $(SRCROOT) macro so that if you move your project, or work on it with others using a remote repo, it will still work. $(SRCROOT) can be thought of as the directory that contains your .xcodeproj file. It might look like this:

$(SRCROOT)/Folder/Folder/<#YourProjectName#>-Bridging-Header.h

Step 3: Add Objective-C Header – .h

Add another .h file and name it CustomObject.h

Step 4: Build your Objective-C Class

In CustomObject.h

#import <Foundation/Foundation.h>

@interface CustomObject : NSObject

@property (strong, nonatomic) id someProperty;

- (void) someMethod;

@end