去掉UItableview headerview黏性(sticky)

     // 去掉UItableview headerview黏性(sticky)
     - (void)scrollViewDidScroll:(UIScrollView *)scrollView
     {
         CGFloat sectionHeaderHeight = ;
         if (scrollView.contentOffset.y<=sectionHeaderHeight&&scrollView.contentOffset.y>=) {
             scrollView.contentInset = UIEdgeInsetsMake(-scrollView.contentOffset.y, , , );
         }
         else if (scrollView.contentOffset.y>=sectionHeaderHeight) {
             scrollView.contentInset = UIEdgeInsetsMake(-sectionHeaderHeight, , , );
         }
     }