为UITapGestureRecognizer

Question

执行此操作时出现运行时错误。我需要帮助！我尝试删除一些代码，但我需要Touch手势，我认为选择器中存在错误，并且不知道如何解码。

让doubletapgesture：UITapGestureRecognizer = UITapGestureRecognizer（target：self，action：Selector（（＆＃34; processDoubleTap：＆＃34;）））我相信这一行导致错误

import UIKit

class ViewController: UIViewController, UICollectionViewDelegateFlowLayout,UICollectionViewDataSource {
     fileprivate let sectionInsets = UIEdgeInsets(top: 50.0, left: 10.0, bottom: 20.0, right: 10.0)
    fileprivate let itemsPerRow: CGFloat = 9
    var collectionView: UICollectionView!
    override func viewDidLoad() {
        super.viewDidLoad()
        //var collectionView: UICollectionView!
        // Do any additional setup after loading the view, typically from a nib.
        let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()

        collectionView = UICollectionView(frame: self.view.frame, collectionViewLayout: layout)
        collectionView.dataSource = self
        collectionView.delegate = self
        collectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "Cell")
        collectionView.backgroundColor = UIColor.white
        self.view.addSubview(collectionView)
        let doubletapgesture : UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: Selector(("processDoubleTap:")))
        doubletapgesture.numberOfTapsRequired = 1
        collectionView.addGestureRecognizer(doubletapgesture)



    }
    func processDoubleTap (sender: UITapGestureRecognizer)
    {
        if sender.state == UIGestureRecognizerState.ended
        {
            let point:CGPoint = sender.location(in: collectionView)
            let indexPath = collectionView.indexPathForItem(at: point)
            if indexPath != nil{
                print("\(indexPath) clicked")
            }

        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        sizeForItemAt indexPath: IndexPath) -> CGSize {
        //2
        let paddingSpace = sectionInsets.left * (itemsPerRow + 1)
        let availableWidth = view.frame.width - paddingSpace
        let widthPerItem = availableWidth / itemsPerRow

        return CGSize(width: widthPerItem, height: widthPerItem)
    }
    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        insetForSectionAt section: Int) -> UIEdgeInsets {
        return sectionInsets
    }
    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return sectionInsets.left
    }
    func collectionView(_ collectionView: UICollectionView,
                        numberOfItemsInSection section: Int) -> Int{
        return  81
    }
    func collectionView(_ collectionView: UICollectionView,
                        cellForItemAt indexPath: IndexPath) -> UICollectionViewCell{
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath as IndexPath)
        cell.backgroundColor = UIColor.orange
        return cell
    }


}