StackView的高度限制会不断修改其包含的视图

Question

我有一个包含两个标签（nameLabel和nicknameLabel）的stackview。我希望两个标签的高度像第一张图片一样保持恒定，但我也希望stackview的位置距其父视图（masterView）顶部30像素。但是，当我为堆栈视图设置topAnchor约束时，当它们应该像第一张图片一样保持恒定时，它将调整按钮的高度。谁能解释这是为什么以及我如何解决此问题？

这是我带有stackview的代码：

class MasterDetailController: UIViewController {

let masterView: UIView = {
    var view = UIView()
    view.translatesAutoresizingMaskIntoConstraints = false
    view.backgroundColor = UIColor.purple


    return view
}()

var labelStackView = UIStackView()

var nameLabel = UILabel()
var nicknameLabel = UILabel()    


override func viewDidLoad() {
    super.viewDidLoad()

    view.addSubview(masterView)

    masterView.addSubview(labelStackView)

    labelStackView.translatesAutoresizingMaskIntoConstraints = false
    labelStackView.axis = .vertical
    labelStackView.distribution = .fill
    labelStackView.alignment = .center
    labelStackView.spacing = 20

    labelStackView.topAnchor.constraint(equalTo: masterView.topAnchor, constant: 30).isActive = true
    labelStackView.heightAnchor.constraint(equalToConstant: 130).isActive = true
    labelStackView.centerXAnchor.constraint(equalTo: masterView.centerXAnchor).isActive = true
    labelStackView.centerYAnchor.constraint(equalTo: masterView.centerYAnchor).isActive = true

    masterView.widthAnchor.constraint(equalTo: view.widthAnchor).isActive = true
    masterView.heightAnchor.constraint(equalTo: view.heightAnchor).isActive = true
    masterView.center = view.center

    labelStackView.addArrangedSubview(nameLabel)
    labelStackView.addArrangedSubview(nicknameLabel)

    setupLayout()

}

func setupLayout() {

    nameLabel.translatesAutoresizingMaskIntoConstraints = false
    nicknameLabel.translatesAutoresizingMaskIntoConstraints = false

    nameLabel.widthAnchor.constraint(equalTo: masterView.widthAnchor, multiplier: 0.75).isActive = true
    nameLabel.heightAnchor.constraint(equalToConstant: 80).isActive = true
    nameLabel.centerXAnchor.constraint(equalTo: masterView.centerXAnchor).isActive = true
    nameLabel.backgroundColor = UIColor.orange
    nameLabel.textAlignment = .center
    nameLabel.font = UIFont(name: "AvenirNext-Regular", size: 30)

    nicknameLabel.widthAnchor.constraint(equalTo: nameLabel.widthAnchor, multiplier: 0.7).isActive = true
    nicknameLabel.heightAnchor.constraint(equalToConstant: 60).isActive = true
    nicknameLabel.font = UIFont(name: "AvenirNext-Regular", size: 15)
    nicknameLabel.textAlignment = .center
    nicknameLabel.backgroundColor = UIColor.cyan


}

}

Here the labels inside the stackview are correct, but the stackview is located in the center of the view when I want it to be located 30 pixels from the top of the view

Here is a picture (current display) of the stackview when I placed its topAnchor 30 pixels from the top, notice that one label inside the stack streches for some reason and I dont want that

我的目标是使按钮成为第一张图片的大小，但要像第二张图片一样固定在视图的顶部。