Swift 4-如果已经选择，则取消选择集合视图单元格

Question

I have a collection view where users can select multiple cells and send the array of index to a server for saving their selection.

everything is working except that when the collection view is created the selected items needs to be clicked two times in order to deselect them.

How can I solve this issue of double clicking ?

extension ThirdViewController: UICollectionViewDelegate, UICollectionViewDataSource {


    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {

        return categoryList.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
         let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath) as! UserCategoryCollectionViewCell

        cell.categoryLbl.text = categoryList[indexPath.row]

        if Defaults.hasKey(.categoryListIndices) {
            if (Defaults[.categoryListIndices]?.contains(indexPath.row))! {
                cell.alpha = 0.1
                cell.isSelected = true
            } else {

                cell.alpha = 1

            }
        }

        return cell
    }


    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        let cell = collectionView.cellForItem(at: indexPath) as! UserCategoryCollectionViewCell


        cell.alpha = 0.1

    }

    func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
        let deselectedCell = collectionView.cellForItem(at: indexPath) as? UserCategoryCollectionViewCell
        deselectedCell?.alpha = 1

        print(deselectedCell?.isSelected)
        collectionView.deselectItem(at: indexPath, animated: false)
    }

}

Answer 1

first of all. add this to your viewDidLoad. collectionView?.allowsMultipleSelection = true

and then add these two functions.

 override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    let cell=collectionView.cellForItem(at: indexPath)
    collectionView.selectItem(at: indexPath, animated: true, scrollPosition: [])
    cell?.backgroundColor = Color.hexStringToUIColor(hex: "#F5A331")
    let lbl = cell?.subviews[1] as! UILabel
    lbl.textColor = Style.cellHighlightedColor
}
 override func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
    collectionView.deselectItem(at: indexPath, animated: true)
    let cell=collectionView.cellForItem(at: indexPath)
    collectionView.deselectItem(at: indexPath, animated: true)

    cell?.backgroundColor = UIColor.white
    let lbl = cell?.subviews[1] as! UILabel
    lbl.textColor = UIColor.darkGray
}
This will do