//監視scrollview是否滾動到底，到底則顯示“更多”按鈕
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
[refreshHeaderViewegoRefreshScrollViewDidScroll:scrollView];//下拉刷新
CGPoint contentOffsetPoint = _tableView.contentOffset;
CGRect frame = _tableView.frame;
if (contentOffsetPoint.y == _tableView.contentSize.height - frame.size.height || _tableView.contentSize.height < frame.size.height)
{
NSLog(@"scroll to the end");
self.btnLoad.hidden = NO;
}
}