https://medium.com/@wdg/swipe-actions-in-swift-58aa965dd04a

Medium_swipe_full.swift

import Foundation
import UIKit

// Extend UIView
extension UIView {
    /// Setup a struct for saving the gesture handlers
    struct gestureHandler {
        /// Gesture "Up"
        static var up: (()->())? = nil
        /// Gesture "Down"
        static var down: (()->())? = nil
        /// Gesture "Left"
        static var left: (()->())? = nil
        /// Gesture "Right"
        static var right: (()->())? = nil
    }
    
    /**
     * Add a swipe action to UIView
     *
     * - Parameter swipeDirection: `.up`,`.down`,`.left`,`.right`
     * - Parameter completionHandler: The completionhandler.
     */
    func swipeAction(
        swipeDirection: UISwipeGestureRecognizer.Direction,
        completionHandler: @escaping ()->()
    ) {
        /// Add swipe handler
        let swiper = UISwipeGestureRecognizer(
            // UIView is the target
            target: self,
            
            // invokeTarget is our responder
            action: #selector(self.invokeTarget(_:))
        )
        
        // Set the direction of the swipe handler
        swiper.direction = swipeDirection
        
        // Add the gesture recognizer to the view
        self.addGestureRecognizer(swiper)
        
        // Switch between directions,
        // Save it to our struct.
        switch swipeDirection {
        case .up:
            // Save the completionHandler to gestureHandler.up
            gestureHandler.up = completionHandler
        case .down:
            // Save the completionHandler to gestureHandler.down
            gestureHandler.down = completionHandler
        case .left:
            // Save the completionHandler to gestureHandler.left
            gestureHandler.left = completionHandler
        case .right:
            // Save the completionHandler to gestureHandler.right
            gestureHandler.right = completionHandler
        default:
            print("Nothing")
        }
    }
    
    /**
     * Respond to a swipe action from UIView
     *
     * - Parameter gesture: The UIGestureRecognizer
     */
    @objc func invokeTarget(_ gesture: UIGestureRecognizer?) {
        /// Unwrap the swipeGesture
        if let swipeGesture = gesture as? UISwipeGestureRecognizer {
            // Switch between the direction
            switch swipeGesture.direction {
            case .up:
                /// Unwrap gestureHandler.up if possible
                guard let execute = gestureHandler.up else {
                    return
                }
                
                execute()
                break;
            case .down:
                /// Unwrap gestureHandler.down if possible
                guard let execute = gestureHandler.down else {
                    return
                }
                
                execute()
                break;
            case .left:
                /// Unwrap gestureHandler.left if possible
                guard let execute = gestureHandler.left else {
                    return
                }
                
                execute()
                break;
            case .right:
                /// Unwrap gestureHandler.right if possible
                guard let execute = gestureHandler.right else {
                    return
                }
                
                execute()
                break;
            default:
                print("N/A")
            }
        }
    }
}