iOS 去掉UItableview header(footer)view黏性(sticky)?

#pragma mark -- UIScrollViewDelegate 代理

#pragma mark 去掉UItableview headerview黏性(sticky)

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {

CGFloat sectionHeaderHeight = 40;

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);

}

}