在表格视图中,我必须滚动到顶部。但我不能保证第一个对象是section 0,第0行。可能我的表视图将从第5节开始。

所以当我调用:

[mainTableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0] atScrollPosition:UITableViewScrollPositionTop animated:NO];

有其他方法滚动到表视图的顶部吗?


当前回答

要在完成时有一个完成,请添加此扩展

// MARK: - UIScrollView

extension UIScrollView {

    /// Animate scroll to top with completion
    ///
    /// - Parameters:
    ///   - duration:   TimeInterval
    ///   - completion: Completion block
    func animateScrollToTop(withDuration duration:  TimeInterval,
                            completion:             @escaping (()->())) {

        UIView.animate(withDuration: duration, animations: { [weak self] in
                self?.setContentOffset(CGPoint.zero, animated: false)
            }, completion: { finish in
                guard finish else {
                    return
                }
                completion()
        })
    }
}

tableView.animateScrollToTop(withDuration: 0.25) { 
    // Finish
}

其他回答

UITableView是UIScrollView的子类,所以你也可以使用:

[mainTableView scrollRectToVisible:CGRectMake(0, 0, 1, 1) animated:YES];

Or

[mainTableView setContentOffset:CGPointZero animated:YES];

在Swift中:

mainTableView.setContentOffset(CGPointZero, animated:true)

在Swift 3及以上版本中:

mainTableView.setContentOffset(.zero, animated: true)
func scrollToTop() {
        NSIndexPath *topItem = [NSIndexPath indexPathForItem:0 inSection:0];
        [tableView scrollToRowAtIndexPath:topItem atScrollPosition:UITableViewScrollPositionTop animated:YES];
}

调用这个函数,无论你想让UITableView滚动到顶部

以下是我在iOS 11上正确运行的方法:

extension UIScrollView {
    func scrollToTop(animated: Bool) {
        var offset = contentOffset
        if #available(iOS 11, *) {
            offset.y = -adjustedContentInset.top
        } else {
            offset.y = -contentInset.top
        }
        setContentOffset(offset, animated: animated)
    }
}

要在完成时有一个完成,请添加此扩展

// MARK: - UIScrollView

extension UIScrollView {

    /// Animate scroll to top with completion
    ///
    /// - Parameters:
    ///   - duration:   TimeInterval
    ///   - completion: Completion block
    func animateScrollToTop(withDuration duration:  TimeInterval,
                            completion:             @escaping (()->())) {

        UIView.animate(withDuration: duration, animations: { [weak self] in
                self?.setContentOffset(CGPoint.zero, animated: false)
            }, completion: { finish in
                guard finish else {
                    return
                }
                completion()
        })
    }
}

tableView.animateScrollToTop(withDuration: 0.25) { 
    // Finish
}

如果你不想要滚动,你可以启动和停止滚动动画,只要你启动它。

    $('document').ready(function() {
    $("html, body").animate({ scrollTop: 0 }, 500);
    return true;
    });

此外,为了使'x'和'y'的值动画化,传入0,0将立即将页面滚动到左上角。

window.scrollTo(x, y);