UICollectionView 单元格未正确突出显示

Question

我正在尝试添加选择多个集合视图单元格并在选择单元格时更改背景颜色的操作。我还想在取消选择单元格时将背景颜色更改回原始颜色。它正在工作，但是当我滚动集合视图时，背景颜色已更改的单元格消失了。我怀疑我可能需要跟踪 indexPath.row 并将其保存到数组中，但我不确定如何正确实现它。

 var indexArray = [Int]()
 func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "ShoeCell", for: indexPath) as! ShoeSizesCell
    cell.backgroundColor = UIColor.textFieldBackgroundColorGray
    cell.shoeSize.textColor = UIColor.init(hexString: "#737373")
      
    return cell
}

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
//    indexArray.append(indexPath.row)

    if let currentCell = collectionView.cellForItem(at: indexPath) as? ShoeSizesCell {

          if currentCell.backgroundColor == UIColor.textFieldBackgroundColorGray {
              currentCell.backgroundColor = .primaryColor
              currentCell.shoeSize.textColor = .white

          }
        else  if currentCell.backgroundColor == .primaryColor {
              currentCell.backgroundColor = UIColor.textFieldBackgroundColorGray
            currentCell.shoeSize.textColor = UIColor.init(hexString: "#737373")

          }
       }

       }

Answer 1

当你在单元格中显示一些数据时，你可以为它制作一个模型。

struct Shoe {
    let size: String
    var isSelected: Bool
}

在ShoeSizesCell中添加Shoe类型变量。并覆盖 UICollectionViewCell

的 isSelected 属性

class ShoeSizesCell: UICollectionViewCell {

    var shoe: Shoe? {
        didSet {
            guard let shoe = shoe else { return }

            self.shoeSize?.text = shoe.size

            if shoe.isSelected {
                self.backgroundColor = .primaryColor
                self.shoeSize.textColor = .white
            }
            else {
                self.backgroundColor = UIColor.textFieldBackgroundColorGray
                self.shoeSize.textColor = UIColor.init(hexString: "#737373")
            }
        }
    }
    
    override var isSelected: Bool {
        didSet {
            if self.isSelected {
                self.backgroundColor = .primaryColor
                self.shoeSize.textColor = .white
            }
            else {
                self.backgroundColor = UIColor.textFieldBackgroundColorGray
                self.shoeSize.textColor = UIColor.init(hexString: "#737373")
            }
        }
    }
}

在UIViewController中，创建一个Shoe类型的数组来保存单元格的数据。您可以在 viewDidLoad() 方法中分配数据。

var shoes = [Shoe]()

将 UICollectionView 的 allowsSelection 和 allowsMultipleSelection 属性设置为 true。

collectionView.allowsSelection = true
collectionView.allowsMultipleSelection = true

在 cellForItem 方法中将 Shoe 数据传递给单元格。

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    if let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "ShoeSizesCell", for: indexPath) as? ShoeSizesCell {
        cell.shoe = shoes[indexPath.item]
        return cell
    }
    return UICollectionViewCell()
}

修改 didSelectItem 方法如下。

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    shoes[indexPath.item].isSelected = true
}

并覆盖 didDeselectItemAt 方法。

func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
    shoes[indexPath.item].isSelected = false
}

UICollectionView 单元格未正确突出显示

UICollectionView Cells not highlighting properly

ios

uicollectionview

uicollectionviewcell

swift