swift - 在 stackview 中隐藏 View 仍然保持约束事件

Question

这段代码可以复制粘贴到一个新创建的项目中:

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let label = createLabel()
        let imageView = createImageView()
        let stackView = UIStackView(arrangedSubviews: [imageView, label])

        stackView.axis = .vertical
        stackView.spacing = 5

        view.addSubview(stackView)
        stackView.translatesAutoresizingMaskIntoConstraints = false
        stackView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        stackView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true

        Timer.scheduledTimer(withTimeInterval: 1, repeats: false) { (_) in
            imageView.isHidden = true
        }
    }

    func createLabel() -> UILabel {
        let label = UILabel(frame: .zero)

        label.text = "Some Text"
        label.setContentHuggingPriority(.required, for: .horizontal)
        label.setContentHuggingPriority(.required, for: .vertical)
        label.backgroundColor = .green

        return label
    }

    func createImageView() -> UIImageView {
        let imageView = UIImageView()

        imageView.backgroundColor = .red
        imageView.heightAnchor.constraint(equalToConstant: 200).isActive = true
        imageView.heightAnchor.constraint(equalTo: imageView.widthAnchor).isActive = true

        return imageView
    }
}

它是 UIStackView 中的一个 UILabel 和一个 UIImageView。当我隐藏 UIImageView 时，我看到 UIStackView 正确地适应了 UILabel 的 高度。但是，UIStackView 不会自行适应 UILabel 的宽度。

我怎样才能让 UIStackView 调整自己的大小到它只有可见的 View /UILabel？我为 UIImageView 的高度 anchor 常量设置了可变约束，并在隐藏 UIImageView 时将其关闭，但 UILabel 对某些人来说消失了奇怪的原因。

Answer 1

添加堆栈 View alignment

This property determines how the stack view lays out its arranged views perpendicularly to its axis. The default value is UIStackView.Alignment.fill.

stackView.alignment = .leading

Stackview 将自身调整为仅可见的 UILabel