ViewController+LongPress.swift

import UIKit

extension ViewController {
    
    /// セルの長押しのリスナーの登録
    func addLongPressGestureListner() {
        let longPressGesture = UILongPressGestureRecognizer(target: self, action: #selector(handleLongGesture(gesture:)))
        collectionView.addGestureRecognizer(longPressGesture)
    }
    
    // MARK: - PRIVATE METHODS
    
    /// セルの長押しジェスチャーのアクション
    ///
    /// - Parameters: gesture
    @objc
    private func handleLongGesture(gesture: UILongPressGestureRecognizer) {
        switch gesture.state {
        case .began:
            guard let selectedIndexPath = collectionView.indexPathForItem(at: gesture.location(in: collectionView)) else {
                break
            }
            collectionView.beginInteractiveMovementForItem(at: selectedIndexPath)
        case .changed:
            collectionView.updateInteractiveMovementTargetPosition(gesture.location(in: gesture.view))
        case .ended:
            collectionView.endInteractiveMovement()
        default:
            collectionView.cancelInteractiveMovement()
        }
    }
}