使用下列代码来控制headerView随tableView的滚动而滚动
CGFloat sectionHeaderHeight = 44;
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);
}else{
scrollView.contentInset = UIEdgeInsetsMake(240, 0, 0, 0);
}
