The error message says that:
Argument of '#selector' refers to instance method 'click()' that is not exposed to Objective-C
Add '@objc' to expose this instance method to Objective-C
By clicking the "Fix" button, Xcode automatically fix this error by placing '@objc' in front of func click() as below:
The complete code to draw a button that prints a message while touching it:
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let button = UIButton(frame: CGRect(x: 0, y: 0, width: 100, height: 30))
button.center = view.center
button.setTitle("Press", for: .normal)
button.setTitleColor(.blue, for: .normal)
button.setTitleColor(.cyan, for: .highlighted)
button.addTarget(self, action: #selector(click), for: UIControlEvents.touchUpInside)
view.addSubview(button)
}
@objc func click() {
print("Pressed!")
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
