Question

我正在尝试在我的视图中使用UIScrollView，因为我要显示的内容不适合屏幕。我纯粹以编程方式工作，似乎无法理解为什么我的UIScrollView在添加约束时根本不起作用。它与框架完美配合，但我认为这是一种笨拙，陈旧的做事方式。我希望能够向滚动视图添加视图，当然，当它离开屏幕时向下滚动。我试图添加一个 topView 作为我希望能够添加的视图之一，并使用scrollview滚动但没有快乐。我哪里错了？任何帮助将受到高度赞赏。

class ScrollTest: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        view.backgroundColor = .white

        setupviews()
    }

    let topView: UIView = {
        let view = UIView()
        view.backgroundColor = .yellow
        return view
    }()

    let containerView: UIView = {
        let view = UIView()
        view.backgroundColor = .white
        return view
    }()

    let scrollView: UIScrollView = {
        let sv = UIScrollView()
        sv.backgroundColor = .white
        sv.translatesAutoresizingMaskIntoConstraints = false
        return sv
    }()

    func setupviews() {
        view.addSubview(scrollView)
        scrollView.addSubview(containerView)

        containerView.addSubview(topView)

        scrollView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        scrollView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
        scrollView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
        scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
//
        _ = containerView.anchor(scrollView.topAnchor, left: scrollView.leftAnchor, bottom: scrollView.bottomAnchor, right: scrollView.rightAnchor, topConstant: 0, leftConstant: 0, bottomConstant: 0, rightConstant: 0, widthConstant: 0, heightConstant: 700)

        _ = topView.anchor(view.topAnchor, left: view.leftAnchor, bottom: nil, right: view.rightAnchor, topConstant: 100, leftConstant: 0, bottomConstant: 0, rightConstant: 0, widthConstant: 0, heightConstant: 50)
    }
}

Answer 1

一些事情。首先，您的containerView遗失translatesAutoresizingMaskIntoConstraints = false。其次，UI对象需要四个约束才能生效。所以你缺少一些容器视图。

这是一个完整的工作代码

let scrollView: UIScrollView = {
    let sv = UIScrollView()
    sv.backgroundColor = .red
    sv.translatesAutoresizingMaskIntoConstraints = false
    return sv
}()

let containerView: UIView = {
    let view = UIView()
    view.backgroundColor = .white
    view.translatesAutoresizingMaskIntoConstraints = false
    return view
}()

override func viewDidLoad() {
    super.viewDidLoad()

    view.addSubview(scrollView)

    scrollView.contentSize = CGSize(width: 320, height: 1500)

    scrollView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
    scrollView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
    scrollView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
    scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true

    scrollView.addSubview(containerView)

    containerView.leftAnchor.constraint(equalTo: scrollView.leftAnchor).isActive = true
    containerView.topAnchor.constraint(equalTo: scrollView.topAnchor).isActive = true
    containerView.widthAnchor.constraint(equalToConstant: 200).isActive = true
    containerView.heightAnchor.constraint(equalToConstant: 100).isActive = true

}

结果就像

Swift：UIScrollView根本无法使用约束？

1 个答案: