CollectionViewCell 不持久

Question

我不完全确定如何提出这个问题，但这是我认为重要的代码...一切都已连接并正常工作（我在单元格上省略了其他设计代码以使问题更具可读性)

在第一个代码片段中，我有我的自定义单元格，它默认变量 "inCurrentMonth" 为 False

class DateCollectionViewCell: UICollectionViewCell {


public var inCurrentMonth: Bool!

required init?(coder aDecoder: NSCoder) {
    super.init(coder:aDecoder)
    //You Code here
    inCurrentMonth = false
}

}

在下面的代码片段中，我正在为每个单元格打印变量 inCurrentMonth - 这总是打印错误

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Calendar", for: indexPath) as! DateCollectionViewCell
    print(cell.inCurrentMonth)
}

最后一段代码显示集合视图在出列时更新每个单元格的 "inCurrentMonth" 变量。如果我在 return 之前打印单元格，它们显然具有正确的 incurrentmonth 值。不管怎样，这个信息什么时候会恢复到错误值？

编辑：标签上的文本值在出队时更新时在集合视图中正确显示

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

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

    switch Direction {  

    case 0:
        if indexPath.row < DaysInMonths[month] + NumberOfEmptyBox{
            cell.DateLabel.text = "\(indexPath.row + 1 - NumberOfEmptyBox)"
            cell.inCurrentMonth = true
        } else {
            cell.DateLabel.text = "\(indexPath.row - DaysInMonths[month] - NumberOfEmptyBox + 1)"
            cell.DateLabel.textColor = UIColor.lightGray
            cell.inCurrentMonth = false
        }
    case 1:
        if indexPath.row < DaysInMonths[month] + NextNumberOfEmptyBox{
            cell.DateLabel.text = "\(indexPath.row + 1 - NextNumberOfEmptyBox)"
            ?????????????THIS DOES WORK?????????????
            cell.inCurrentMonth = true
        } else {
            !!!!!!!!!!!!!THIS DOES NOT WORK!!!!!!!!!!!!!!!
            cell.DateLabel.text = "\(indexPath.row - DaysInMonths[month] - NextNumberOfEmptyBox + 1)"
            cell.DateLabel.textColor = UIColor.lightGray
            cell.inCurrentMonth = false
        }
    case -1:
        if indexPath.row < DaysInMonths[month] + PreviousNumberOfEmptyBox{
            ?????????????THIS DOES WORK?????????????
            cell.DateLabel.text = "\(indexPath.row + 1 - PreviousNumberOfEmptyBox)"
            !!!!!!!!!!!!!THIS DOES NOT WORK!!!!!!!!!!!!!!!
            cell.inCurrentMonth = true
        } else {
            cell.DateLabel.text = "\(indexPath.row - DaysInMonths[month] - PreviousNumberOfEmptyBox + 1)"
            cell.DateLabel.textColor = UIColor.lightGray
            cell.inCurrentMonth = false
        }
    default:
        fatalError()
    }

    if Int(cell.DateLabel.text!)! < 1 { //here we hide the negative numbers or zero

        var previousMonth: Int = month-1
        if previousMonth == -1 {
            previousMonth = 11
        }
        let previousDay: Int = DaysInMonths[previousMonth] - NumberOfEmptyBox + (indexPath.row) + 1
        cell.DateLabel.text = "\(previousDay)"
        cell.DateLabel.textColor = UIColor.lightGray
        cell.inCurrentMonth = false
    }

Answer 1

in the code snippet below I am printing the variable inCurrentMonth for each of the cells - THIS ALWAYS PRINTS FALSE

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Calendar", for: indexPath) as! DateCollectionViewCell
    print(cell.inCurrentMonth)
}

dequeueReusableCell 创建一个单元格的新实例，而不是这个请使用 UICollectionView

的 func cellForItem(at: IndexPath) -> UICollectionViewCell? 方法

CollectionViewCell 不持久

CollectionViewCell not persistent

ios

swift

uicollectionview

uicollectionviewlayout