UICollctionView didSelectItemAt问题

Question

我试图在didSelectItemAt的帮助下更改collectionviewcell中的UIImage。当我在开头选择单元格时它正在工作，但是当我向下滚动并向上滚动时，图像又恢复到它们的状态，并且更改的图像会移动到不同的单元格。

First cell selected Image

Scrolled down then came up Image

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "collection_cell", for: indexPath) as! RateCardCollectionViewCell
        let tempString = "\(NSLocalizedString("base_url", comment: ""))\(itemImageLink[indexPath.row])"
        let urlnew:String = tempString.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed)!
        let url = URL(string: urlnew)
        cell.rateCardImage.kf.setImage(with: url,placeholder: UIImage(named: "Junkart_Bin.png"))
        cell.label.text = itemName[indexPath.row]
        cell.itemRate.text = itemRate[indexPath.row]
        cell.layer.cornerRadius = 3
        cell.card.backgroundColor = UIColor.white
        cell.card.layer.masksToBounds = false
        cell.card.layer.shadowColor = UIColor.black.withAlphaComponent(0.2).cgColor
        cell.card.layer.shadowOffset = CGSize(width: 0, height: 0)
        cell.card.layer.shadowOpacity = 1   //0.8
        return cell
    }

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        let cell = collectionView.cellForItem(at: indexPath) as! RateCardCollectionViewCell
        if self.selectedRate == nil {
            cell.changeImagetoSelected()
            self.selectedRate = [Int]()
            self.selectedRate.append(indexPath.row)
        }
        else {

        }
    }

以下是UICollectionViewCell类

class RateCardCollectionViewCell: UICollectionViewCell {


    @IBOutlet weak var label: UILabel!
    @IBOutlet weak var rateCardImage: UIImageView!
    @IBOutlet weak var card: UIView!
    @IBOutlet weak var itemRate: UILabel!
    @IBOutlet weak var selected_rate_image: UIImageView!
    func changeImagetounSelected() {
        selected_rate_image.image = UIImage(named: "unselected_rate")
    }
    func changeImagetoSelected() {
        selected_rate_image.image = UIImage(named: "selected_rate")
    }
}

请帮助!!

Answer 1

检查在创建单元格cell时selectedRate上添加的cellForItemAt创建索引。

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "collection_cell", for: indexPath) as! RateCardCollectionViewCell
        // Your remaining codes are here.

        if selectedRate.contains(IndexPath.row) {
           cell.changeImageToSelected()
        } else {
           cell.changeImageTounselected()
        }
        return cell
    }

Answer 2

这是因为收集视图使他的细胞出列。因此，您需要在dataModel中保留您的选择，并获取是否选择了单元格。因此，在viewController和cellForItemAt方法调用中保留selectedIndex：

if(self.selectedIndex == indexPath.row){
    cell.changeImageToSelected()
}
else{
    cell.changeImageTounselected()
}

滚动时，这将保留您的选择