Ios 实现 滑动cell 伸缩的核心代码

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CGFloat viewHeight = scrollView.height + scrollView.contentInset.top;
    NSArray *cells = self.tableView.visibleCells;
    for (int i = ; i < cells.count; i++) {

        UITableViewCell *cell = cells[i];

        CGFloat y = cell.centerY - scrollView.contentOffset.y;
        CGFloat p = y - viewHeight / ;

        CGFloat scale = cos(p / viewHeight * 0.8) * 0.85;

        [UIView animateWithDuration:0.15 delay: options:UIViewAnimationOptionCurveEaseInOut|UIViewAnimationOptionAllowUserInteraction | UIViewAnimationOptionBeginFromCurrentState animations:^{

            cell.transform = CGAffineTransformMakeScale(scale, scale);

        } completion:^(BOOL finished) {

        }];

    }

}