addArrangedSubview 代码有什么问题？

Question

我试图了解 addArrangedSubview 的工作原理，所以我尝试了一个虚拟项目。这是我的 VC ：

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var stackOutlet: UIStackView!
override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    let newView = UIView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
    newView.backgroundColor = UIColor.darkGray

    let newView2 = UIView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
    newView2.backgroundColor = UIColor.blue
    stackOutlet.addArrangedSubview(newView)
    stackOutlet.addArrangedSubview(newView2)
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

当我启动应用程序时，没有出现任何内容。我想我必须在 stackView 中设置一些约束？

Answer 1

好的，看在大家的份上：你需要使用这个 =

mapView.heightAnchor.constraint(equalToConstant: 200).isActive = true
mapView.widthAnchor.constraint(equalToConstant: 200).isActive = true

addArrangedSubview 代码有什么问题？

What is wrong with that addArrangedSubview code?

swift

uistackview