(void)scrollViewDidScroll:(UIScrollView *)scrollView{
//headerView
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);
}
}

//footerView
if (scrollView == _tableView) {
//去掉UItableview的section的footerview黏性
CGFloat sectionFooterHeight = 44;
if (scrollView.contentOffset.y<=sectionFooterHeight && scrollView.contentOffset.y>=0) {
scrollView.contentInset = UIEdgeInsetsMake(0, 0, -sectionFooterHeight, 0);
} else if (scrollView.contentOffset.y>=sectionFooterHeight) {
//footerview 一直隱藏在底部。
scrollView.contentInset = UIEdgeInsetsMake(0, 0, 0, 0);
}
}
}