Collection View-如何在每个部分中仅选择一个单元格

Question

我的收藏夹视图有多个部分。我想要达到的目的是，用户只能在每个部分中选择一个单元格（答案）。选择单元格（答案）后，背景颜色将改变。

我没有做的是那个例子：当用户单击第1节中的一个单元格时，我只想取消选择第1节中的另一个单元格。

下面是我的一些代码

    @IBOutlet var step3CollectionView: UICollectionView!

    var HexColor = HexColorClass()
    var dataPageThree : json_PageThree!    
    var step3AnswerArray : [Int] = []


    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {

        var frameCount = dataPageThree.step_instruction.first!.subquestions.count

        for i in 0..<frameCount{

            if indexPath.section == i {
                step3AnswerArray[i] = (dataPageThree.step_instruction.first?.subquestions[i].subquestion_selection_answerNums![indexPath.row])!


            let callCell = self.step3CollectionView.cellForItem(at: indexPath) as? Step3CollectionViewCell

            callCell!.answerLabel.backgroundColor = HexColor.hexStringToUIColor(hex: "117577")

            callCell!.answerLabel.textColor = UIColor.white

            }

        }

    }

 func collectionView(_ collectionView: UICollectionView, shouldSelectItemAt indexPath: IndexPath) -> Bool {


        let indexPaths = collectionView.indexPathsForSelectedItems
        if (indexPaths?.count) ?? 0 > 0 {

            /// If you need simple way
            for index in indexPaths! {
                if index.section == indexPath.section {
                    self.step3CollectionView.deselectItem(at: index, animated: true) // if want deselect previous selection

                    let callCell = self.step3CollectionView.cellForItem(at: index) as? Step3CollectionViewCell

                            callCell!.answerLabel.backgroundColor = UIColor.white

                            callCell!.answerLabel.textColor = UIColor.black
                    //return false  //if you do not want further selection
                }
            }


        }

        return true
    }

需要一些指导。

Answer 1

override func viewDidLoad() {
    super.viewDidLoad()
    self.step3CollectionView.allowsMultipleSelection = true
}

现在，UICollectionViewDelegate方法collectionView(_: shouldSelectItemAt:)应该看起来像，

func collectionView(_ collectionView: UICollectionView, shouldSelectItemAt indexPath: IndexPath) -> Bool {
   collectionView.indexPathsForSelectedItems?.filter({ $0.section == indexPath.section }).forEach({ collectionView.deselectItem(at: $0, animated: false) })
    return true
}

此外，请勿基于backgroundColour选择更改cell或shouldSelectItemAt中didSelectItemAt的cell's。这使得代码庞大且多余。

应该在UICollectionViewCell子类中通过覆盖
isSelected属性来完成。
class CollectionViewCell: UICollectionViewCell {
    override var isSelected: Bool {
        didSet {
            self.backgroundColor = isSelected ? .blue : .lightGray
        }
    }
}