UItableViewのsectionの粘りを落とし、ぶら下がらないようにします

//     UITableView      ，    section，                         
- (void)scrollViewDidScroll:(UIScrollView *)scrollView 
{  
    if (scrollView == _tableView) 
    {  
        CGFloat sectionHeaderHeight = 36;
 
        if (scrollView.contentOffset.y <= sectionHeaderHeight && scrollView.contentOffset.y >= 0) 
        {  
            scrollView.contentInset = UIEdgeInsetsMake(-scrollView.contentOffset.y, 0, 0, 0);  
        }
         else if (scrollView.contentOffset.y >= sectionHeaderHeight) 
        {  
            scrollView.contentInset = UIEdgeInsetsMake(-sectionHeaderHeight, 0, 0, 0);  
        }  
    }  
}