去掉UItableview section headerview黏性

UITabelView在style为plain时，在上拉是section始终粘在最顶上而不是跟随滚动而消失或者出现

可以通过设置UIEdgeInsetsMake:

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

if (scrollView == self.myTableView) {

CGFloat sectionHeaderHeight = 40;（section头部的高度）

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);

}

}

}