类型 'UIGestureRecognizer' 没有成员 'State'

Question

I get the following error in the LongPressViewController class.

import UIKit

class LongPressViewController: UIViewController {

    @IBOutlet weak var imgView: UIImageView!
    @IBAction func btnTekan(_ sender: UILongPressGestureRecognizer) {
        if sender.state == UIGestureRecognizer.State.began {
            let  alertController = UIAlertController(title: nil, message: "Long Press terdeteksi", preferredStyle: .alert)
            alertController.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))

            self.present(alertController, animated: true)

        }
    }


    override func viewDidLoad() {
        super.viewDidLoad()
        let longPressGesture = UILongPressGestureRecognizer(target: self, action: #selector(handleLongPress(_:)))

    }
    @objc func handleLongPress(_ recognizer: UILongPressGestureRecognizer){
        switch recognizer.state {
        case .began:
            UIView.animate(withDuration: 0.05,
                           animations: {
                            self.imgView.transform = CGAffineTransform(scaleX: 1.5, y: 1.5)
            },
                           completion: nil)
        case .ended:
            UIView.animate(withDuration: 0.05) {
                self.imgView.transform = CGAffineTransform.identity
            }
        default:
            break
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

Answer 1

Warning: your code is incomplete

You should indicate what error is reported on which line of your code.

As is, your code may warn you that the constant longPressGesture declared and initialized in viewDidLoad() was never used. This is not an error, but just a friendly reminder that this line has no effect. You may attach the recognizer to the controlled view by adding the following line:

view.addGestureRecognizer(longPressGesture)

Alternatively, you can declare longPressGesture as an @IBOutlet and attach it in Interface Builder.

Further up where you use State , the property state implies already the type UIGestureRecognizer.State , so you may shorten your line to

if sender.state == .began {