我终于明白了，我希望这更容易理解。

你通常可以通过添加一个基本的UIView到滚动视图作为一个“内容视图”来绕过这个警告，就像他们提到的，让它和你的滚动视图一样大，在这个内容视图上，设置这6个参数。

如您所见，您总共需要6个参数!哪一个在正常情况下，你复制了两个约束，但这是避免故事板错误的方法。

import UIKit

class ViewController: UIViewController {

    //
    let scrollView: UIScrollView = {
        
        let sv = UIScrollView()
        sv.translatesAutoresizingMaskIntoConstraints = false
        return sv
    }()
    
    let lipsumLbl: UILabel = { // you can use here any of your subview
        
        let lbl = UILabel()
        lbl.translatesAutoresizingMaskIntoConstraints = false
        lbl.text = """
        Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fusce eleifend nisi sit amet mi aliquet, ut efficitur risus pellentesque. Phasellus nulla justo, scelerisque ut libero id, aliquet ullamcorper lectus. Integer id iaculis nibh. Duis feugiat mi vitae magna tincidunt, vitae consequat dui tempor. Donec blandit urna nec urna volutpat, sit amet sagittis massa fringilla. Pellentesque luctus erat nec dui luctus, sed maximus urna fermentum. Nullam purus nibh, cursus vel ex nec, pulvinar lobortis leo. Proin ac libero rhoncus, bibendum lorem sed, congue sapien. Donec commodo, est non mollis malesuada, nisi massa tempus ipsum, a varius quam lorem vitae nunc.
        
        Cras scelerisque nisi dolor, in gravida ex ornare a. Interdum et malesuada fames ac ante ipsum primis in faucibus. Maecenas vitae nisl id erat sollicitudin accumsan sit amet viverra sapien. Etiam scelerisque vulputate ante. Donec magna nibh, pharetra sed pretium ac, feugiat sit amet mi. Vestibulum in ipsum vitae dui vehicula pulvinar eget ut lectus. Fusce sagittis a elit ac elementum. Fusce iaculis nunc odio, at fermentum dolor varius et. Suspendisse consectetur congue massa non gravida. Sed id elit vitae nulla aliquam euismod. Pellentesque accumsan risus dolor, eu cursus nibh semper id.
        
        Vestibulum vel tortor tellus. Suspendisse potenti. Pellentesque id sapien eu augue placerat dictum. Fusce tempus ligula at diam lacinia congue in ut metus. Maecenas volutpat tellus in tellus maximus imperdiet. Integer dignissim condimentum lorem, id luctus nisi maximus at. Nulla pretium, est sit amet mollis eleifend, tellus nulla viverra dolor, ac feugiat massa risus a lectus. Pellentesque ut pulvinar urna, blandit gravida ipsum. Nullam volutpat arcu nec fringilla auctor. Integer egestas enim commodo, faucibus neque ac, rutrum magna. Vivamus tincidunt rutrum auctor. Cras at rutrum felis. Fusce elementum lorem ut pharetra venenatis.
        """
        lbl.textColor = .darkGray
        lbl.font = UIFont.systemFont(ofSize: 16)
        lbl.numberOfLines = 0
        return lbl
    }()
    
    //======================================================================//
    //
    // MARK:- viewDidLoad
    //
    override func viewDidLoad() {
        super.viewDidLoad()
        
        setupViews()
        setupAutoLayout()
    }
    
    func setupViews() {
        
        title = "ScrollView Demo"
        view.backgroundColor = .white
        view.addSubview(scrollView)
        scrollView.addSubview(lipsumLbl)
    }
    
    func setupAutoLayout() {
        
        scrollView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        scrollView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
        scrollView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
        scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
        
        lipsumLbl.topAnchor.constraint(equalTo: scrollView.topAnchor).isActive = true
        lipsumLbl.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        lipsumLbl.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
        lipsumLbl.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor).isActive = true
    }
}

输出:

[在XCode 7.2和iOS 9.2中测试]

对我来说，抑制Storyboard错误和警告的方法是将滚动视图和内容视图(在我的例子中，是一个stackview)的固有大小设置为Placeholder。这个设置可以在故事板的大小检查器中找到。它说-设置设计时间内在内容大小只影响在界面生成器中编辑时的视图。视图在运行时没有这个固有的内容大小。

所以，我想我们设置这个不会错。

注意:在storyboard中，我已经将scrollview的所有边固定在superview上，将stackview的所有边固定在scrollview上。在我的代码中，我已经为scrollview和stackview设置了translatesAutoresizingMaskIntoConstraints为false。我还没有提到内容大小。当堆栈视图动态增长时，在故事板中设置的约束确保堆栈是可滚动的。

故事板警告快把我逼疯了，我不想为了抑制警告而水平或垂直地将事物居中。

Xcode 11+， Swift 5。

根据@WantToKnow的回答，我解决了我的问题，我准备了视频和代码

在我的情况下，我收到了不正确的内容大小和内容大小模糊的问题在iPad，但在iPhone的情况下工作。我在故事板中做了以下更改来解决这个问题。

在UIView中添加scrollview并添加约束前置，上，后，下到0,0,0,0。 设置滚动视图的高度根据要求，例如。One hundred. 添加UIView到滚动视图，并添加约束领先，顶部，尾部和底部0,0,0,0和对齐中心(X)和中心(Y)约束。 在滚动视图的尺寸检查器中取消选择“内容布局指南”。

This error took me a while to track down, initially I tried pinning the ScrollView's size but the error message clearly says "content size". I made sure everything I pinned from the top of the ScrollView was also pinned to the bottom. That way the ScrollView can calculate its content height by finding the height of all the objects & constraints. This solved the ambiguous content height, the width is pretty similar... Initially I had most things X centered in the ScrollView, but I had to also pin the objects to the side of the ScrollView. I don't like this because the iPhone6 might have a wider screen but it will remove the 'ambiguous content width' error.