如果contentSize低于边界怎么办?

对于Swift来说，它是:

scrollView.setContentOffset(CGPointMake(0, max(scrollView.contentSize.height - scrollView.bounds.size.height, 0) ), animated: true)

我还发现了另一种有用的方法，在这种情况下，你正在使用UITableview(这是UIScrollView的子类):

[(UITableView *)self.view scrollToRowAtIndexPath:scrollIndexPath atScrollPosition:UITableViewScrollPositionBottom animated:YES];

迅速:

你可以使用这样的扩展:

extension UIScrollView {
    func scrollsToBottom(animated: Bool) {
        let bottomOffset = CGPoint(x: 0, y: contentSize.height - bounds.size.height)
        setContentOffset(bottomOffset, animated: animated)
    }
}

Use:

scrollView.scrollsToBottom(animated: true)

CGFloat yOffset = scrollView.contentOffset.y;

CGFloat height = scrollView.frame.size.height;

CGFloat contentHeight = scrollView.contentSize.height;

CGFloat distance = (contentHeight  - height) - yOffset;

if(distance < 0)
{
    return ;
}

CGPoint offset = scrollView.contentOffset;

offset.y += distance;

[scrollView setContentOffset:offset animated:YES];

滚动到顶部

- CGPoint topOffset = CGPointMake(0, 0);
- [scrollView setContentOffset:topOffset animated:YES];

滚动到底部

- CGPoint bottomOffset = CGPointMake(0, scrollView.contentSize.height - self.scrollView.bounds.size.height);
 - [scrollView setContentOffset:bottomOffset animated:YES];

扩展UIScrollView添加一个scrollToBottom方法:

extension UIScrollView {
    func scrollToBottom(animated:Bool) {
        let offset = self.contentSize.height - self.visibleSize.height
        if offset > self.contentOffset.y {
            self.setContentOffset(CGPoint(x: 0, y: offset), animated: animated)
        }
    }
}