Objective C framework for swift app, error: Argument passed to call that takes no arguments

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I am building an objective C framework for a swift app. I am trying to use a function in swift by an objective C header file that is imported.

interface MyApi : NSObject

+ (void)init:(NSDictionary *)launchOptions;

@end

@implementation MyApi

+ (void)init:(NSDictionary *)launchOptions {
    ...
}
@end

These are the .h and .m files in obj C. In swift I am trying to call the function like this:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        MyApi.init(launchOptions)
        return true
    }

But I keep getting the error: Argument passed to call that takes no arguments

at the line I am calling the function. Any thoughts?

bridging-header swift objective-c ios
1 Answers

This syntax:

MyApi.init(launchOptions)

calls the initialiser of MyApi. Note that init is a keyword in Swift and has special meaning! Since MyApi inherits from NSObject, it inherits the parameterless initialiser, which is what the Swift compiler thinks that you are trying to call. This is the same as:

MyApi(launchOptions)

However, your init method in Objective-C is not an initialiser for a MyApi object, is it? It's just a regular class method called init. To call it in Swift, you have to escape the special meaning of the init keyword by adding backticks around it:

MyApi.`init`(launchOptions)

The backticks are quite astonishing, so I'd suggest that you rename init to something else, like setup.

user_51335850
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