如何在集合视图中单选单元格？

Question

这是代码正常工作,但当我将滚动我的集合视图,然后另一个单元格也被选中,例如18个图像可用,并在运行时首先显示六个,当我将选择任何一个六个然后也选择另一个2单元格我在这里混淆为什么已选择另外两个单元格请给我解决方案

在这里,我在主要展示故事板上采取了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;

}

Answer 1

发生这种情况是因为collectionView重用了单元格;

您应该将选定单元格的IndexPath存储在变量中:

@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
}

而不是"indexPath中的行的单元格"检查:

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
}

Answer 2

感谢Alberto Scampini这段代码为swift 3.1

var selectedIndexPath: IndexPath?

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

    let cell = self.collectionView.dequeueReusableCell(withReuseIdentifier: "SegmentChoiceCVCell", for: indexPath) as! SegmentChoiceCVCell
    //configure cell

    if selectedIndexPath != nil && indexPath == selectedIndexPath {
        cell.checkIcon.backgroundColor = UIColor.black

    }else{

        cell.checkIcon.backgroundColor = UIColor.white
    }

    return cell

}



func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {

    let cell = collectionView.cellForItem(at: indexPath) as! SegmentChoiceCVCell

        cell.checkIcon.backgroundColor = UIColor.black
    self.selectedIndexPath = indexPath

}

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

        cell.checkIcon.backgroundColor = white
    selectedIndexPath = nil
}