来自 UICollectionView 的 didSelectItemAt 和 didDeSelectItemAt

Question

如果我didSelectItemAt在 a 中使用UICollectionView，我想更改所选单元格的颜色。和didDeselectItemAt，我想替换以前选择的单元格的颜色。

搬家前效果很好。但是，移动到最右侧将无法正常工作。为什么是这样？

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

        return 14 
 }

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CalendarCollectionViewCell", for: indexPath ) as! CalendarCollectionViewCell

        cell.calendarDayLabel.text = calendar?.twoWeeksDay![ indexPath.row ]
        cell.calendarDateLabel.text = calendar?.twoWeeksDate![ indexPath.row ]

        return cell

 }

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

        let cell = collectionView.cellForItem(at: indexPath) as? CalendarCollectionViewCell


        cell?.calendarDayLabel.textColor = UIColor( red: 255, green: 0, blue: 0, alpha: 1.0 )
        cell?.calendarDateLabel.textColor = UIColor( red: 255 , green: 255 , blue: 255 , alpha: 1.0 )
        cell?.calendarCircleImageView.isHidden = false

        self.selectYear = self.calendar?.twoWeeksYear![ indexPath.row ]
        self.selectMonth = self.calendar?.twoWeeksMonth![ indexPath.row ]
        self.selectDate = self.calendar?.twoWeeksDate![ indexPath.row ]
        self.selectDay = self.calendar?.twoWeeksDay![ indexPath.row ]

        self.selectDateTime.text = self.selectYear! + "? " + self.selectMonth! + "? " + self.selectDate! + "? " + self.selectDay!

        self.selectDateTime.isHidden = false

}

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


        let cell = collectionView.cellForItem(at: indexPath) as? CalendarCollectionViewCell
        cell?.calendarDayLabel.textColor = UIColor( red: 0, green: 0, blue: 0, alpha: 1.0 )
        cell?.calendarDateLabel.textColor = UIColor( red: 0 , green: 0 , blue: 0 , alpha: 1.0 )
        cell?.calendarCircleImageView.isHidden = true

 }

在此处输入图片说明

Answer 1

因为细胞被重复利用

 var selectedIndex:IndexPath?

//

 func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CalendarCollectionViewCell", for: indexPath ) as! CalendarCollectionViewCell

       if indexPath == selectedIndex {

                cell.calendarDayLabel.textColor = UIColor( red: 255, green: 0, blue: 0, alpha: 1.0 )
                cell.calendarDateLabel.textColor = UIColor( red: 255 , green: 255 , blue: 255 , alpha: 1.0 )
                cell.calendarCircleImageView.isHidden = false

       }
       else {

              cell.calendarDayLabel.textColor = UIColor( red: 0, green: 0, blue: 0, alpha: 1.0 )
              cell.calendarDateLabel.textColor = UIColor( red: 0 , green: 0 , blue: 0 , alpha: 1.0 )
              cell.calendarCircleImageView.isHidden = true

       }


}

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

    selectedIndex = indexPath
    collectionView.reloadData()

 }

消除didDeselectItemAt