ios - 如何只修改从 collectionView 中选择的项目的大小和位置？

Question

我有一个 Collection View ，当我选择一个项目时，我想放大该图像并添加一个框架。我这样做了，但其余的图像也在移动。这就是我所做的:

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

    if ([selectedIndexPath isEqual:indexPath]) {
       selectedIndexPath = nil;
        [self.player stop];

        CollectionViewCell *cellOne =  [collectionView cellForItemAtIndexPath:indexPath];
        cellOne.inner.hidden=YES;


        recipeImageView.frame=CGRectMake(recipeImageView.frame.origin.x, recipeImageView.frame.origin.y, 100, 100);
        recipeImageView.layer.borderColor = [[UIColor blackColor] CGColor];

    }
    else {
        // select new cell
        celulaSelectata=indexPath;
        UICollectionViewCell  *cell = [collectionView cellForItemAtIndexPath:indexPath];
        recipeImageView = (UIImageView *)[cell viewWithTag:100];

        CollectionViewCell *cellOne =  [collectionView cellForItemAtIndexPath:indexPath];

        recipeImageView.frame=CGRectMake(recipeImageView.frame.origin.x, recipeImageView.frame.origin.y, 120, 120);
        cellOne.inner.frame=recipeImageView.frame;

如何仅修改所选项目的大小和位置？

Answer 1

selectedIndexPath创建 UICollectionViewLayoutAttributes对于选定的单元格并调用 invalidateItemsAtIndexPaths:(NSArray *)indexPaths更新所选 UICollectionViewLayoutAttributes 的单元格

子类化您的 UICollectionViewLayout并在您的UICollectionViewLayout中添加功能并使任何 indexPath 无效更新

- (UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewLayoutAttributes *attribute = [super layoutAttributesForItemAtIndexPath:indexPath];
    if ([indexPath isEqual:selectedIndexPath]) {
        //set attributes
        //attribute.frame = //setframe;
    }
    return attribute;
}