Ios 如何在Swift 3中的可拖动UIView之间创建连接线？然后测量线的角度

我需要在屏幕上有两个视图进行拖动（通过

UIPangestureRecognitiser

）和一条连接线，这样当我自由移动视图时，该线保持连接（就像视图之间的绳子一样）。测量这条线的角度。 这是到目前为止我的代码

    var rect1:UIView!
    var rect2:UIView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // create my two views

        rect1 = UIView(frame: CGRect(x: 50, y: 150, width: 40, height: 40))
        rect1.backgroundColor = UIColor.orange
        self.view.addSubview(rect1)

        rect2 = UIView(frame: CGRect(x: 200, y: 150, width: 40, height: 40))
        rect2.backgroundColor = UIColor.yellow
        self.view.addSubview(rect2)

        // and the UIPanGestureRecognizer objects

        let gesture1 = UIPanGestureRecognizer(target: self, action: #selector(dragView))
        rect1.addGestureRecognizer(gesture1)

        let gesture2 = UIPanGestureRecognizer(target: self, action: #selector(dragView))
        rect2.addGestureRecognizer(gesture2)

        // add mi connecting line between 

    func addLine(fromPoint start: rect1.center, toPoint end:rect2.center) 
        }

    // create the func for moving the views

    func dragView(_ sender: UIPanGestureRecognizer)
    {        
        let point = sender.location(in: self.view)    
        let theDraggedView = sender.view!
        theDraggedView.center = point        
    }     
    // and the func for line creation    


     func addLine(fromPoint start: CGPoint, toPoint end:CGPoint) 
    {
    let line = CAShapeLayer()
    let linePath = UIBezierPath()
    linePath.move(to: start)
    linePath.addLine(to: end)
    line.path = linePath.cgPath
    line.strokeColor = UIColor.red.cgColor
    line.lineWidth = 2
    line.lineJoin = kCALineJoinRound
    self.view.layer.addSublayer(line)
    }
}

我现在是股票！！ 如果在dragView中再次使用addline func，将创建数百行。

---

而且不知道下一步要做什么，这是因为当您反复调用

addLine

函数时，并没有删除上一行

对于remove previous line，在类的顶部声明

var line=CAShapeLayer（）

，这样您就可以得到您绘制的上一行，然后无论何时调用

addLine

函数，只要在开始时从superview中删除上一行即可，如下所示：

line.removeFromSuperlayer()

您的完整代码为：

import UIKit

class ViewController: UIViewController {

    var rect1:UIView!
    var rect2:UIView!
    var line = CAShapeLayer()

    override func viewDidLoad() {
        super.viewDidLoad()

        rect1 = UIView(frame: CGRect(x: 50, y: 150, width: 40, height: 40))
        rect1.backgroundColor = UIColor.orange
        self.view.addSubview(rect1)

        rect2 = UIView(frame: CGRect(x: 200, y: 150, width: 40, height: 40))
        rect2.backgroundColor = UIColor.yellow
        self.view.addSubview(rect2)

        // and the UIPanGestureRecognizer objects

        let gesture1 = UIPanGestureRecognizer(target: self, action: #selector(dragView))
        rect1.addGestureRecognizer(gesture1)

        let gesture2 = UIPanGestureRecognizer(target: self, action: #selector(dragView))
        rect2.addGestureRecognizer(gesture2)

        addLine(start: rect1.center, toPoint:rect2.center)
    }

    func dragView(_ sender: UIPanGestureRecognizer) {

        let point = sender.location(in: self.view)
        let theDraggedView = sender.view!
        theDraggedView.center = point
        addLine(start: rect1.center, toPoint:rect2.center)
    }


    func addLine(start: CGPoint, toPoint end:CGPoint) {

        line.removeFromSuperlayer()
        let linePath = UIBezierPath()
        linePath.move(to: start)
        linePath.addLine(to: end)
        line.path = linePath.cgPath
        line.strokeColor = UIColor.red.cgColor
        line.lineWidth = 2
        line.lineJoin = kCALineJoinRound
        self.view.layer.addSublayer(line)
    }
}

您的结果将是：

---

效果很好，非常感谢。最后一步，我需要移动3个对象作为一个孔，这样我就可以对齐照片上的线并测量角度（例如三角形）。我尝试移动主视图，但屏幕开始抖动！如果你能帮忙的话！又是坦斯克！！请用您尝试过的代码提出不同的问题。谢谢