滚动视图不水平滚动

Posted 2023-03-16

【中文标题】滚动视图不水平滚动

【英文标题】：Scroll view not scrolling horizontal

【发布时间】：2019-03-18 12:03:58

【问题描述】：

我有一个自定义视图，我在父级中设置它：

func setup()
    view.backgroundColor = .gray
    view.addSubview(chartView)
    chartView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
    chartView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
    chartView.topAnchor.constraint(equalTo: view.topAnchor, constant: statusAndNavigationBarHeight).isActive = true
    chartView.heightAnchor.constraint(equalToConstant: Dimensions.chartHeight.value).isActive = true

然后在那个视图中我尝试设置一个滚动：

scroll = UIScrollView.init(frame: CGRect(x: 0.0, y: 0.0, width: scrollWidth(), // print 728.0
                                                 height: Double(Dimensions.chartHeight.value))) // print 400.0
    scroll.isScrollEnabled = true
    scroll.showsHorizontalScrollIndicator = true
    addSubview(scroll)

仅此而已，当我启动应用程序时，我无法水平拖动和滚动，在调试编辑器中我看不到它是大宽度的滚动视图。

【参考方案1】：

scrollView 不会以它的大小滚动，它需要一个定义它的内容大小的内容，例如

class ViewController: UIViewController 

    override func viewDidLoad() 
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        let chartView = UIView()
        chartView.translatesAutoresizingMaskIntoConstraints = false
        chartView.backgroundColor = .red
        view.backgroundColor = .gray
        view.addSubview(chartView)
        chartView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        chartView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
        chartView.topAnchor.constraint(equalTo: view.topAnchor, constant: 100).isActive = true
        chartView.heightAnchor.constraint(equalToConstant:200).isActive = true
        let scroll = UIScrollView(frame: CGRect(x: 0.0,
            y: 0.0,
            width: UIScreen.main.bounds.size.width, // print 728.0
            height: 200.0))
        scroll.isScrollEnabled = true
        scroll.showsHorizontalScrollIndicator = true
        chartView.addSubview(scroll)
        let www = UIView()
        www.backgroundColor = .green
        www.translatesAutoresizingMaskIntoConstraints = false
         scroll.addSubview(www)
        www.leftAnchor.constraint(equalTo: scroll.leftAnchor).isActive = true
        www.rightAnchor.constraint(equalTo: scroll.rightAnchor).isActive = true
        www.topAnchor.constraint(equalTo: scroll.topAnchor).isActive = true
        www.bottomAnchor.constraint(equalTo: scroll.bottomAnchor).isActive = true
        www.heightAnchor.constraint(equalToConstant:200).isActive = true
        www.widthAnchor.constraint(equalTo: view.widthAnchor,multiplier:2.0).isActive = true
        scroll.addSubview(www)

    

【讨论】：

为什么要添加两次视图？