swift 4 : scrollViewDidScroll not working

Question

1. 我创建了第一个 View Controller “MainViewController”，并将带有导出 contentContainer 的容器 View 放入其中。
2. 我创建了第二个 View Controller “AboutContentViewController”并将其放入 ScrollView
3. 我以编程方式连接 Container View 和 AboutContentViewController:

class MainViewController: UIViewController {
    @IBOutlet weak var contentContainer: UIView!

    override func viewDidLoad() {
        let contentControllerName = "AboutContentViewController"
        if let contentController = storyboard?.instantiateViewController(withIdentifier: contentControllerName) {
            contentContainer.addSubview(contentController.view)
        }
    }
}

1. 我尝试使用此代码捕获 scrollViewDidScroll 事件

class AboutContentViewController: UIViewController, UIScrollViewDelegate {
    @IBOutlet weak var topGalleryScrollView: UIScrollView!
       
    override func viewDidLoad() {
        super.viewDidLoad()
        
        topGalleryScrollView.contentSize = CGSize(width: 3750.0, height: 417.0)
        topGalleryScrollView.delegate = self
    }
    
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        print("scrollViewDidScroll called")
    }
}

在此上下文中，scrollViewDidScroll 事件不起作用

Answer 1

我已经解决了问题。在将其 View 添加到容器之前，需要将 AboutContentViewController 作为 subview Controller 添加到 MainVewController:

class MainViewController: UIViewController {
    @IBOutlet weak var contentContainer: UIView!

    override func viewDidLoad() {
        let contentControllerName = "AboutContentViewController"
        if let contentController = storyboard?.instantiateViewController(withIdentifier: contentControllerName) {
            addChildViewController(contentController)
            contentContainer.addSubview(contentController.view)
        }
    }
}