我怎么能让一个UIScrollView滚动到我的代码底部?或者用更一般的方式,到子视图的任意点?


当前回答

只是对已有答案的一个改进。

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

它还负责底部的嵌入(以防你在键盘可见时使用它来调整滚动视图)

其他回答

类别来拯救!

将此添加到共享实用程序头的某处:

@interface UIScrollView (ScrollToBottom)
- (void)scrollToBottomAnimated:(BOOL)animated;
@end

然后是那个实用程序实现:

@implementation UIScrollView(ScrollToBottom)
- (void)scrollToBottomAnimated:(BOOL)animated
{
     CGPoint bottomOffset = CGPointMake(0, self.contentSize.height - self.bounds.size.height);
     [self setContentOffset:bottomOffset animated:animated];
}
@end

然后在任何你喜欢的地方执行它,例如:

[[myWebView scrollView] scrollToBottomAnimated:YES];

用于水平ScrollView

如果你像我一样有一个水平ScrollView,想要滚动到它的结尾(在我的情况下,它的最右边),你需要改变接受的答案的某些部分:

objective - c

CGPoint rightOffset = CGPointMake(self.scrollView.contentSize.width - self.scrollView.bounds.size.width + self.scrollView.contentInset.right, 0 );
[self.scrollView setContentOffset:rightOffset animated:YES];

斯威夫特

let rightOffset: CGPoint = CGPoint(x: self.scrollView.contentSize.width - self.scrollView.bounds.size.width + self.scrollView.contentInset.right, y: 0)
self.scrollView.setContentOffset(rightOffset, animated: true)

Xamarin的。iOS版本的接受答案

var bottomOffset = new CGPoint (0,
     scrollView.ContentSize.Height - scrollView.Frame.Size.Height
     + scrollView.ContentInset.Bottom);

scrollView.SetContentOffset (bottomOffset, false);

对我没用,当我在UITableViewController上使用它时。tableView (iOS 4.1),添加footerView后。它滚动出边界,显示黑屏。

可选择的解决方案:

 CGFloat height = self.tableView.contentSize.height; 

 [self.tableView setTableFooterView: myFooterView];
 [self.tableView reloadData];

 CGFloat delta = self.tableView.contentSize.height - height;
 CGPoint offset = [self.tableView contentOffset];
 offset.y += delta;

 [self.tableView setContentOffset: offset animated: YES];

正如这里所解释的 https://janeshswift.com/ios/swift/how-to-scroll-to-a-position-programmatically-in-uiscrollview/

我们可以创建一个自定义UIScrollView扩展为

extension UIScrollView {
    
    func scrollToTop(animated: Bool = false) {
        setContentOffset(CGPoint(x: contentOffset.x, y: -adjustedContentInset.top), animated: animated)
    }
    
    var bottomContentOffsetY: CGFloat {
        max(contentSize.height - bounds.height + adjustedContentInset.bottom, -adjustedContentInset.top)
    }
    
    func scrollToBottom(animated: Bool = false) {
        setContentOffset(CGPoint(x: contentOffset.x, y: bottomContentOffsetY), animated: animated)
    }
    
    func scrollToLeading(animated: Bool = false) {
        setContentOffset(CGPoint(x: -adjustedContentInset.left, y: contentOffset.y), animated: animated)
    }
    
    var trailingContentOffsetX: CGFloat {
        max(contentSize.width - bounds.width + adjustedContentInset.right, -adjustedContentInset.left)
    }
    
    func scrollToTrailing(animated: Bool = false) {
        setContentOffset(CGPoint(x: trailingContentOffsetX, y: contentOffset.y), animated: animated)
    }
    
    func scrollViewToVisible(_ view: UIView, animated: Bool = false) {
        scrollRectToVisible(convert(view.bounds, from: view), animated: true)
    }
    
    var isOnTop: Bool {
        contentOffset.y <= -adjustedContentInset.top
    }
    
    var isOnBottom: Bool {
        contentOffset.y >= bottomContentOffsetY
    }
    
}

把它当作——

DispatchQueue.main.async {
    self.itemsScrollView.scrollToBottom()
}