1

I have created swift extension for the class ViewController and defined one method in it. When I try to call same that method from the same Obj-c ViewController, it gives me an error below:

No visible @interface for 'ViewController' declares the selector 'testMe

My Code is as below:

Objective-C class

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

@end

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

[self testMe]; // No visible @interface for 'ViewController' declares the selector 'testMe'

}
@end

Swift extension:
// ViewController+extnesion.swift

import UIKit

@objc public extension ViewController {
    
    func testMe() {
        print("Vish")
    }
}
2

Your .m file needs to import the compatibility header that the Swift compiler emits.

3

Ah yeah, thank you. Below import made it worked.

import "ExtensionTest-Swift.h"