以编程方式向垂直堆栈视图添加视图打破了垂直堆栈视图的约束

Question

So I have a vertical stack view in a simple layout. When I add a view through Interface Builder I see the view in the stack view no issues.

When I then add views programmatically to the UIStackView it breaks the constraints and the added views appear at the top of the window. I'm confused as to why it would break the constraints of the stack view.

 func buildCats(theJson:JSON){
     //self.verticalStack.subviews.forEach({ $0.removeFromSuperview() })
    print(theJson)
    if let infos = self.swiftyJsonvar["info"].array{
        for info in infos{
            guard let v = UINib(nibName: "ticketOrderView", bundle: nil).instantiate(withOwner: nil, options: nil)[0] as? UIView else { return }
            v.translatesAutoresizingMaskIntoConstraints = false
            self.verticalStack.addArrangedSubview(v)

        }
    }
}

Answer 1

The added subviews need constraints, as they have no intrinsic size. Try:

v.heightAnchor.constraint(greaterThanOrEqualToConstant: 30).isActive = true v.widthAnchor.constraint(greaterThanOrEqualToConstant: 200).isActive = true

Hmmm.... I'm doubting this now... I suspect the issue may be related to adding the views on a background thread. Maybe run the loop on the main thread?

Edit 2: Ah... the problem I'm betting now is related to what you're doing with the view / subviews inside your "ticketOrderView"

For an example, see: https://github.com/DonMag/ScratchPad