ios - 如何使用 UIView 画线？

Question

我可以使用 CGContext 绘制线条。如何使用 UIView 绘制具有相同坐标的线？以后想移动线条，需要用到UIView。

func DrawLine()
{
    UIGraphicsBeginImageContext(self.view.frame.size)
    imageView.image?.draw(in: CGRect(x: 0, y: 0, width: self.view.frame.width, height: self.view.frame.height))
    let context = UIGraphicsGetCurrentContext()

    let lineWidth : CGFloat = 5

    context?.move(to: CGPoint(x: 100, y: 100))
    context?.addLine(to: CGPoint(x: self.view.frame.width - 100, y: 100))
    context?.setBlendMode(CGBlendMode.normal)
    context?.setLineCap(CGLineCap.round)
    context?.setLineWidth(lineWidth)
    context?.setStrokeColor(UIColor(red: 0, green: 0, blue: 0, alpha: 1.0).cgColor)
    context?.strokePath()

    context?.move(to: CGPoint(x: self.view.frame.width/2, y: 100))
    context?.addLine(to: CGPoint(x: self.view.frame.width/2, y: 700))
    context?.strokePath()

    imageView.image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
}
override func viewDidLoad() 
{        
    super.viewDidLoad()
    DrawLine()
}

Answer 1

1. 将 CAShapeLayer 添加到 UIView

   let shapeLayer = CAShapeLayer()
   view.layer.addSublayer(shapeLayer)
   

2. 将形状层路径设置为线条

   shapeLayer.path = // some CGPath you create
   

参见:https://stackoverflow.com/a/40556796/3937了解如何使用线条制作 CGPath。