Question

如果我在didSelectItemAt中使用UICollectionView，我想更改所选单元格的颜色。并使用didDeselectItemAt，我要替换先前选择的单元格的颜色。

在移动之前效果很好。但是，移到最右边将无法正常工作。为什么会这样？

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! + "년 " + self.selectMonth! + "월 " + self.selectDate! + "일 " + 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

 }

enter image description here

Answer 1

因为细胞被重复使用

 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()

 }

删除didDeselectItemAt

Answer 2

您要在这里实现什么？多选状态？还是只是选择状态？无论哪种方式，您都应该真正地继承UICollectionViewCell并覆盖isSelected，而不是让集合视图委托来管理选择的外观。

对于第一个示例，只需在集合视图上启用allowsMultipleSelection并在点击它们时选择单元格即可。您可以覆盖isHighlighted来临时查看用户正在触摸的单元格。

对于后者，您只需要覆盖isSelected并根据此状态设置颜色即可。

override var isSelected: Bool {
    didSet {
        if isSelected {
            calendarDayLabel.textColor = UIColor( red: 255, green: 0, blue: 0, alpha: 1.0 )
            calendarDateLabel.textColor = UIColor( red: 255 , green: 255 , blue: 255 , alpha: 1.0 )
        } else {
            // do opposite color
        }
        calendarCircleImageView.isHidden = !isSelected
     }
}

UICollectionView中的didSelectItemAt和didDeSelectItemAt

2 个答案: