.vertical UIStackView 将所有按钮叠加在一起，位于堆栈顶部

Question

我不确定发生了什么。图像显示了问题。这些应该是三个带有标题和图像的不同按钮。

我玩过 .distribution、button 和 stackView 帧大小的各种排列，强制按钮的帧大小，甚至使按钮成为覆盖 intrinsicContentSize 并强制大小的视图的子类。

在此之前，我以各种方式在堆栈视图方面取得了相当大的成功。不确定这里有什么不同。我注意到通过为其中一个按钮明确设置框架，如下面的代码所示，它导致文本跨越两行，这表明该框架具有一些有意义的效果，只是不在堆栈视图的布局上。

var buttonStack: UIStackView! = nil

var sortBy = SortType.nexus

enum SortType : String, RawRepresentable, CaseIterable { case simple, nexus, orthogonal }

func configureSortButtons() { // configures buttons as stackView, also implements button handlers as closures.
        let attributedContainer = AttributeContainer([ .font : UIFont.systemFont(ofSize: 14), .foregroundColor : UIColor.blue])
        let buttons = SortType.allCases.map { sortType in
            let name = sortType.rawValue.capitalized
            var config = UIButton.Configuration.plain()
            config.image = UIImage(named: name + "GenericButton")?.withRenderingMode(.alwaysTemplate).resize(to: CGSizeMake(15, 15))
            config.imagePadding = 8
            config.attributedTitle = AttributedString("Sort by " + name, attributes: attributedContainer)
            let button = UIButton(configuration: config)
            button.translatesAutoresizingMaskIntoConstraints = false
            button.addAction(UIAction(handler: { _ in self.sortBy = sortType; self.showFiles(self.fileList) }), for: .primaryActionTriggered)
            button.frame = CGRectMake(0, 0, 100, 25)
            return button
        }
        buttonStack = UIStackView(arrangedSubviews: buttons)
        buttonStack.translatesAutoresizingMaskIntoConstraints = false
        buttonStack .axis             = .vertical
        buttonStack .alignment        = .fill
        buttonStack .distribution     = .fillEqually
        buttonStack .spacing          = 10
        view.addSubview(buttonStack)
        buttonStack.frame = CGRectMake(0, 0, 150, 150)
        buttonStack.backgroundColor = .gray
    }

    NSLayoutConstraint.activate([
        buttonStack.topAnchor.constraint(equalTo: view.topAnchor, constant: 0),
        buttonStack.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 0),
        buttonStack.widthAnchor.constraint(equalToConstant: buttonStack.frame.size.width),
        buttonStack.heightAnchor.constraint(equalToConstant: buttonStack.frame.size.height),
  ])