ios - 如何正确制作包含一些 viewControllers 的容器 View (以编程方式)？

Question

我想以编程方式创建一个容器 View ，其中包含一堆 View Controller 。我有一个分段 Controller ，当用户点击一个按钮时，它应该显示某个 viewController 而无需进行 segue。 我在 ViewController 中拥有一切， 我想知道如何让分段 Controller 在点击时正确显示某个 View Controller 。

func setUpSegmentedControl() {
    let seg = UISegmentedControl(items: ["1", "2", "3"])
    seg.selectedSegmentIndex = 0
    seg.translatesAutoresizingMaskIntoConstraints = false

    seg.layer.cornerRadius = 8  
    seg.backgroundColor = UIColor.white 
    seg.addTarget(self, action: #selector(changeColor(sender:)), for: .valueChanged)
   view.addSubview(seg)

           NSLayoutConstraint.activate([
 seg.centerXAnchor.constraint(equalTo: view.centerXAnchor),                                                     seg.centerYAnchor.constraint(equalTo: view.centerYAnchor),                                     seg.leadingAnchor.constraint(equalTo: view.leadingAnchor),                                   seg.trailingAnchor.constraint(equalTo: view.trailingAnchor),                                seg.heightAnchor.constraint(equalToConstant: 50)

        ])
}   

 @objc func changeColor(sender: UISegmentedControl) {
    switch sender.selectedSegmentIndex {
    case 0:
        addChild(FirstViewController())

        print("1")
    case 1:
        addChild(SecondViewController())

    print("2")
    default:
        addChild(ThirdViewController())

        print("3")
    }
}

Answer 1

要以编程方式将 View Controller 添加到容器 View ，除了调用 addChild 之外，还需要调用 addSubview 和 didMove。

let firstViewController = FirstViewController()
addChild(firstViewController)
firstViewController.view.translatesAutoresizingMaskIntoConstraints = false
containerView.addSubview(firstViewController.view) // replace `containerView` with the name of the view that's supposed to contain the VC's view

// add constraints or set frame manually
let trailingConstraint = firstViewController.view.trailingAnchor.constraint(equalTo: view.trailingAnchor)
let leadingConstraint = firstViewController.view.leadingAnchor.constraint(equalTo: view.leadingAnchor)
let topConstraint = firstViewController.view.topAnchor.constraint(equalTo: view.topAnchor)
let bottomConstraint = firstViewController.view.bottomAnchor.constraint(equalTo: view.bottomAnchor)
NSLayoutConstraint.activate([trailingConstraint, leadingConstraint, topConstraint, bottomConstraint])

firstViewController.didMove(to parent: self)

如果您想以编程方式删除 subview Controller :

let child = children.first // or other way to identify your VC
child?.willMove(toParentViewController: nil)
child?.view.removeFromSuperview()
child?.view.removeFromParentViewController()

Example project