Swift：创建动画自定义视图错误

Question

我以编程方式创建了一个好习惯，一个投递箱。

除了动画之外，一切都正常。

这是我致电self.setNeedsLayout()

时动画的结果

在这里，当我不使用self.setNeedsLayout()

我的自定义视图我将其插入了堆栈视图

这是我的自定义视图：

class FittoBoxView: UIView {

    let headerView: UIView =  {
        let view = UIView()
        view.translatesAutoresizingMaskIntoConstraints = false
        view.backgroundColor = .gray
        return view
    }()

    var open = true

    var heightContraint: NSLayoutConstraint!

    override init(frame: CGRect) {
        super.init(frame: frame)
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
    }

}


extension FittoBoxView {

    func registerView(with constraint: NSLayoutConstraint) {
        heightContraint = constraint
        translatesAutoresizingMaskIntoConstraints = false
        backgroundColor = .red

        // Adding header
        let tap = UITapGestureRecognizer(target: self, action: #selector(self.handleTap(_:)))
        headerView.addGestureRecognizer(tap)

        addSubview(headerView)
        headerView.leadingAnchor.constraint(equalTo: leadingAnchor).isActive = true
        headerView.trailingAnchor.constraint(equalTo: trailingAnchor).isActive = true
        headerView.heightAnchor.constraint(equalToConstant: 45).isActive = true

        heightContraint.constant = 400
    }


    @objc func handleTap(_ sender: UITapGestureRecognizer? = nil) {
        if open {
            heightContraint.constant = 45
        } else {
            heightContraint.constant = 400
        }

        self.setNeedsLayout() // <------ IR 

        UIView.animate(withDuration: 1) {
            self.layoutIfNeeded()
        }

        open = !open
    }

}

该框的切换位于handleTap()函数中

在我的控制器中，我创建如下视图：

let boxView = FittoBoxView()
stackView.insertArrangedSubview(boxView, at: 1)

let height = boxView.heightAnchor.constraint(equalToConstant: 100)
height.isActive = true

boxView.registerView(with: height)

为什么当我使用setNeedLayout时，视图会跳转？标签没有动画

我该如何制作动画，或者只是框的主体在动画中发生？