NSLayoutConstraint：在视图之间添加线

Question

我正面临着NSLayoutConstraint问题。我以编程方式创建了一个视图，并希望在两个视图之间添加一条线。创建了线，但它被添加到视图中，如图所示：

如何在视图之间保留这些线条。这是我的代码：

  import UIKit
class ViewController: UIViewController {
    @IBOutlet weak var dashBoardView: UIView!
    override func viewDidLoad() {
        super.viewDidLoad()
        self.dashBoardView.removeFromSuperview()
        // Do any additional setup after loading the view, typically from a nib.
        var x :Int
        var y : Int
        x = 0;
        y=50;
        for i in 0..<5 {
            //setting view frame
            var view = UIView(frame: CGRect(x: x,y : y,width: 50,height:50))
            view.backgroundColor = UIColor.red
            self.view.layer.cornerRadius = 5.0
             self.view.addSubview(view)
            //y for next view should be height of previous view and margin between view
            y += 100
            //setting the lineView
            let pathView = PathView()
            pathView.translatesAutoresizingMaskIntoConstraints = false
            view.addSubview(pathView)
                NSLayoutConstraint.activate([
                pathView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
                pathView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
                pathView.topAnchor.constraint(equalTo: view.topAnchor),
                pathView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
                ])
            pathView.backgroundColor = .clear
            let path = UIBezierPath()
            path.move(to: CGPoint(x: 10, y:10))
            path.addLine(to: CGPoint(x: 100, y: 100))
            path.lineWidth = 3
            pathView.path = path
        }

    }

}

这是我的PathView类;

import UIKit
class PathView : UIView
{
    var path: UIBezierPath?
    { didSet { setNeedsDisplay() } }
    var pathColor: UIColor = .blue
    { didSet { setNeedsDisplay() } }

    override func draw(_ rect: CGRect) {
        // stroke the path
        pathColor.setStroke()
        path?.stroke()
    }
}

我知道由于视图中添加了那些活动约束而添加了行。但我很困惑，我怎么能在视图外添加它们。任何帮助或建议将真的很感激。

Answer 1

请更新您的约束：

NSLayoutConstraint.activate([
            pathView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            pathView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            pathView.topAnchor.constraint(equalTo: view.bottomAnchor),


            pathView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 100.0)
            ])