2019-06-19

tableview视图可见范围内cell
NSArray *visiblePaths = [self.tableView indexPathsForVisibleRows];

UICollectionView视图可见范围内cell
NSArray *visiblePaths = [_collectionView indexPathsForVisibleItems];
刷新某个cell
[self.collectionView reloadItemsAtIndexPaths:@[indexPath]];