swift-绘制虚线

参考:http://www.jianshu.com/p/f9009968c735

效果图：

虚线边框.png

代码：

    //绘制虚线边框
    func addDashdeBorderLayer(byView view:UIView, color:UIColor,lineWidth width:CGFloat){
        let shapeLayer = CAShapeLayer()
        let size = view.frame.size
        
        let shapeRect = CGRectMake(10, 10, size.width-20, size.height-20)
        shapeLayer.bounds = shapeRect
        shapeLayer.position = CGPoint(x: size.width*0.5, y: size.height*0.5)
        shapeLayer.fillColor = UIColor.clear.cgColor
        shapeLayer.strokeColor = color.cgColor
        shapeLayer.lineWidth = width
        shapeLayer.lineJoin = kCALineJoinRound
        //
        shapeLayer.lineDashPattern = [3,4]
        let path = UIBezierPath(roundedRect: shapeRect, cornerRadius: 5)
        shapeLayer.path = path.cgPath
        view.layer.addSublayer(shapeLayer)
        
    }

效果图2：

虚线2.png

代码：

    func addDashdeBorderLayer(by view:UIView){
        let imgV:UIImageView = UIImageView(frame: CGRect(x: 0, y: view.sizeHeight-5, width: view.sizeWidth, height: 5))
        view.addSubview(imgV)
        UIGraphicsBeginImageContext(imgV.frame.size)
        
        let context = UIGraphicsGetCurrentContext()
        context?.setLineCap(CGLineCap.square)
        
        let lengths:[CGFloat] = [10,30,]
        context?.setStrokeColor(UIColor.red.cgColor)
        context?.setLineWidth(2)
        context?.setLineDash(phase: 0, lengths: lengths)
        context?.move(to: CGPoint(x: 0, y: 3))
        context?.addLine(to: CGPoint(x: view.sizeWidth, y: 3))
        context?.strokePath()
        
        context?.setStrokeColor(UIColor.blue.cgColor)
        context?.setLineWidth(2)
        context?.setLineDash(phase: 0, lengths: lengths)
        context?.move(to: CGPoint(x: 20, y: 3))
        context?.addLine(to: CGPoint(x: view.sizeWidth, y: 3))
        context?.strokePath()
        imgV.image = UIGraphicsGetImageFromCurrentImageContext()
     //结束
        UIGraphicsEndImageContext()
    }