假设我在UIStackView中添加了更多可以显示的视图,我如何让UIStackView滚动?


当前回答

苹果的自动布局指南包括了一个关于使用滚动视图的完整部分。一些相关片段:

Pin the content view’s top, bottom, leading, and trailing edges to the scroll view’s corresponding edges. The content view now defines the scroll view’s content area. (Optional) To disable horizontal scrolling, set the content view’s width equal to the scroll view’s width. The content view now fills the scroll view horizontally. (Optional) To disable vertical scrolling, set the content view’s height equal to the scroll view’s height. The content view now fills the scroll view horizontally.

此外:

你的布局必须完全定义内容视图的大小(除了 . ...当内容视图比滚动视图高时,滚动视图允许垂直滚动。当内容视图比滚动视图宽时,滚动视图启用水平滚动。

To summarize, the scroll view's content view (in this case, a stack view) must be pinned to its edges and have its width and/or height otherwise constrained. That means that the contents of the stack view must be constrained (directly or indirectly) in the direction(s) in which scrolling is desired, which might mean adding a height constraint to each view inside a vertically scrolling stack view, for example. The following is an example of how to allow for vertical scrolling of a scroll view containing a stack view:

// Pin the edges of the stack view to the edges of the scroll view that contains it
stackView.topAnchor.constraint(equalTo: scrollView.topAnchor).isActive = true
stackView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
stackView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
stackView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor).isActive = true

// Set the width of the stack view to the width of the scroll view for vertical scrolling
stackView.widthAnchor.constraint(equalTo: scrollView.widthAnchor).isActive = true

其他回答

我也想做同样的事情,偶然发现了这个优秀的帖子。如果您希望使用锚API以编程方式完成此操作,则可以采用这种方式。

总之,在UIScrollView中嵌入UIStackView,并设置UIStackView的锚约束来匹配UIScrollView的锚约束:

stackView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
stackView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
stackView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor).isActive = true
stackView.topAnchor.constraint(equalTo: scrollView.topAnchor).isActive = true
stackView.widthAnchor.constraint(equalTo: scrollView.widthAnchor).isActive = true

到2020年为止。

100%故事板或100%代码。

这个例子是垂直的:


下面是最简单的解释:

有一个空白的全屏场景 添加一个滚动视图。Control-drag从滚动视图拖到基本视图,添加左-右-上-下,全部为零。 在滚动视图中添加堆栈视图。从堆栈视图Control-drag到滚动视图,添加左-右-上-下,全部为零。 在堆栈视图中放置两个或三个标签。

为了清晰,标签的背景颜色为红色。设置标签高度为100。

现在设置每个UILabel的宽度: 令人惊讶的是,从UILabel控件拖动到滚动视图,而不是堆栈视图,并选择相同的宽度。

重复:

不要从UILabel控件拖动到UILabel的父控件,而是拖到祖父控件。(换句话说,一直到滚动视图,不要到堆栈视图。)

就是这么简单。这就是秘诀。

秘密提示——苹果臭虫: 只有一件物品是不行的!添加几个标签以使演示正常工作。

你就完成了。

提示:必须为每个新项添加高度。任何滚动堆栈视图中的每个项都必须具有固有大小(例如标签)或添加显式高度约束。


另一种方法:

回顾一下上面的方法:令人惊讶的是,将标签的宽度设置为滚动视图的宽度(而不是堆栈视图)。

这里有另一种方法……

从堆栈视图拖动到滚动视图,并添加一个“宽度相等”约束。这看起来很奇怪,因为你已经左右固定了,但这就是你怎么做的。不管看起来有多奇怪,这就是秘密。

所以你有两个选择:

令人惊讶的是,将堆栈视图中每个项的宽度设置为scrollview祖父类(而不是stackview父类)的宽度。

or

令人惊讶的是,设置一个“宽度相等”的stackview到scrollview -即使你有stackview的左右边固定到scrollview。

需要明确的是,只使用其中一种方法,不要同时使用两种方法。

在你的场景中放置一个滚动视图,并调整它的大小,使它充满场景。然后,在滚动视图中放置一个堆栈视图,并在堆栈视图中放置添加项按钮。一旦一切就绪,就设置以下约束条件:

Scroll View.Leading = Superview.LeadingMargin
Scroll View.Trailing = Superview.TrailingMargin
Scroll View.Top = Superview.TopMargin
Bottom Layout Guide.Top = Scroll View.Bottom + 20.0
Stack View.Leading = Scroll View.Leading
Stack View.Trailing = Scroll View.Trailing
Stack View.Top = Scroll View.Top
Stack View.Bottom = Scroll View.Bottom
Stack View.Width = Scroll View.Width

代码:堆栈视图。宽度=滚动视图。宽度是关键。

例如,垂直堆栈视图/滚动视图(使用EasyPeasy自动布局):

let scrollView = UIScrollView()
self.view.addSubview(scrollView)
scrollView <- [
    Edges(),
    Width().like(self.view)
]

let stackView = UIStackView(arrangedSubviews: yourSubviews)
stackView.axis = .vertical
stackView.distribution = .fill    
stackView.spacing = 10
scrollView.addSubview(stackView)
stackView <- [
    Edges(),
    Width().like(self.view)
]

只要确保每个子视图的高度都已定义!

这里投票最多的答案中的约束条件对我来说是有效的,我已经将在我的故事板中创建的约束条件的图像粘贴在下面。

我确实提到了两个问题,但其他人应该注意:

After adding constraints similar to those in in the accepted answer, I'd get the red autolayout error Need constraints for: X position or width. This was solved by adding a UILabel as a subview of the stack view. I'm adding the subviews programmatically, so I originally had no subviews on the storyboard. To get rid of the autolayout errors, add a subview to the storyboard, then remove it on load before adding your real subviews and constraints. I originally attempted to add UIButtons to the UIStackView. The buttons and views would load, but the scroll view would not scroll. This was solved by adding UILabels to the Stack View instead of buttons. Using the same constraints, this view hierarchy with the UILabels scrolls but the UIButtons does not. I'm confused by this issue, as the UIButtons do seem to have an IntrinsicContentSize (used by the Stack View). If anyone knows why the buttons don't work, I'd love to know why.

下面是我的视图层次结构和约束,供参考: