如何在集合视图中单选单元格？

Chirag Gajjar 发表于 Dev

奇拉格·加杰尔（Chirag Gajjar）

这些代码可以正常工作，但是当我滚动集合视图时，还选择了另一个单元格，例如，有18张图像可用，并且在运行时首先显示6张图像，此时我将选择任意一个位置，然后自动选择下6个位置图像。为什么一次选择两个单元格使我感到困惑。请给我解决方案

在此处输入图片说明

在这里，我在主节目情节提要板上占据了6个单元格

UICollectionViewFlowLayout *flowLayout = (UICollectionViewFlowLayout*)self.collectionView.collectionViewLayout;

flowLayout.minimumLineSpacing = 15;
CGFloat availableWidthForCells = CGRectGetWidth(self.collectionView.frame) - flowLayout.sectionInset.left - flowLayout.sectionInset.right - flowLayout.minimumInteritemSpacing *2;

cellWidth = availableWidthForCells /6;
    NSLog(@"cellWidth:%f",cellWidth);
flowLayout.itemSize = CGSizeMake(cellWidth, cellWidth);

这是我的Didselect和didDeselect方法

-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{

    UICollectionViewCell* cell = [collectionView cellForItemAtIndexPath:indexPath];

    cell.layer.cornerRadius = cellWidth / 2.0;
    cell.layer.backgroundColor = [UIColor blackColor].CGColor;
    NSLog(@"INDEXPATH:-%ld",(long)indexPath.row);
}
-(void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath{

    UICollectionViewCell* cell = [collectionView cellForItemAtIndexPath:indexPath];
    cell.layer.cornerRadius = cellWidth / 2.0;
    cell.layer.backgroundColor = [UIColor whiteColor].CGColor;

}

阿尔贝托·斯坎皮尼（Alberto Scampini）

发生这种情况是因为collectionView重用了单元格；

您应该将所选单元格的IndexPath存储在变量中：

对象：

@property (nonatomic, retain) NSIndexPath *selectedIndexPath;

-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {

    UICollectionViewCell* cell = [collectionView cellForItemAtIndexPath:indexPath];

    cell.layer.backgroundColor = [UIColor blackColor].CGColor;
    NSLog(@"INDEXPATH:-%ld",(long)indexPath.row);

    self.selectedIndexPath = indexPath
}
-(void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath{

    UICollectionViewCell* cell = [collectionView cellForItemAtIndexPath:indexPath];
    cell.layer.backgroundColor = [UIColor whiteColor].CGColor;

    self.selectedIndexPath = nil
}

斯威夫特：

var selectedIndexPath: IndexPath?

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    let cell = collectionView.cellForItem(at: indexPath)

    cell.layer.backgroundColor = UIColor.black

    self.selectedIndexPath = indexPath
}

func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
    let cell = collectionView.cellForItem(at: indexPath)

    cell.layer.backgroundColor = UIColor.white

    self.selectedIndexPath = nil
}

比在“ indexPath行的单元格”中检查：

对象：

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {

    UICollectionViewCell* cell = [collectionView cellForItemAtIndexPath:indexPath];
    cell.layer.cornerRadius = cellWidth / 2.0;
    if (self.selectedIndexPath != nil && indexPath == self.selectedIndexPath) {
        cell.layer.backgroundColor = [UIColor blackColor].CGColor;
    else {
        cell.layer.backgroundColor = [UIColor whiteColor].CGColor;
   }

    return cell
}

斯威夫特：

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

    let cell = collectionView.cellForItem(at: indexPath)
    cell.layer.cornerRadius = cellWidth / 2

    if self.selectedIndexPath != nil && indexPath == self.selectedIndexPath {
        cell.layer.backgroundColor = UIColor.black
    else {
        cell.layer.backgroundColor = UIColor.white
    }
}

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