iOS Swift and Objective-C interoperability Using Objective-C Classes in Swift
Example
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.hto 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:
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:
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
In CustomObject.m
#import "CustomObject.h"
@implementation CustomObject
- (void) someMethod {
NSLog(@"SomeMethod Ran");
}
@end
Step 5: Add Class to Bridging-Header
In YourProject-Bridging-Header.h:
#import "CustomObject.h"
Step 6: Use your Object
In SomeSwiftFile.swift:
var instanceOfCustomObject: CustomObject = CustomObject()
instanceOfCustomObject.someProperty = "Hello World"
println(instanceOfCustomObject.someProperty)
instanceOfCustomObject.someMethod()
No need to import explicitly, that's what the bridging header is for.
