创建一个高度为1的虚线

///创建一个高为1的线
    func config() {
        let lineView = UIView(frame: CGRect(x: 2, y: 300, width: self.view.frame.size.width - 4, height: 1))
        self.view.addSubview(lineView)
        drawDashLine(lineView: lineView, lineLength: 10, lineSpacing: 5, lineColor: UIColor.red)
    }
    
    /**
     *  通过 CAShapeLayer 方式绘制虚线
     *  lineView:       需要绘制成虚线的view
     *  lineLength:     线宽
     *  lineSpacing:    线间距
     **/
    func drawDashLine(lineView : UIView, lineLength : Int ,lineSpacing : Int,lineColor : UIColor){
        let shapeLayer = CAShapeLayer()
        shapeLayer.bounds = lineView.bounds
        //只要是CALayer这种类型,他的anchorPoint默认都是(0.5,0.5)
        shapeLayer.anchorPoint = CGPoint(x: 0, y: 0)
        //shapeLayer.fillColor = UIColor.blue.cgColor
        shapeLayer.strokeColor = lineColor.cgColor
        
        shapeLayer.lineWidth = lineView.frame.size.height
        shapeLayer.lineJoin = kCALineJoinRound
        
        shapeLayer.lineDashPattern = [NSNumber(value: lineLength),NSNumber(value: lineSpacing)]
        
        let path = CGMutablePath()
        path.move(to: CGPoint(x: 0, y: 0))
        path.addLine(to: CGPoint(x: lineView.frame.size.width, y: 0))
        
        shapeLayer.path = path
        lineView.layer.addSublayer(shapeLayer)
    }