用CALayer绘制虚线

我能够使用下面的代码绘制一个虚线框：

CAShapeLayer *shapeLayer = [CAShapeLayer layer]; CGRect shapeRect = CGRectMake(0.0f, 0.0f, 200.0f, 100.0f); [shapeLayer setBounds:shapeRect]; [shapeLayer setPosition:CGPointMake(self.coreImageView_.frameX, self.coreImageView_.frameBottom - self.coreImageView_.frameHeight/2)]; [shapeLayer setFillColor:[[UIColor clearColor] CGColor]]; [shapeLayer setStrokeColor:[[UIColor whiteColor] CGColor]]; [shapeLayer setLineWidth:2.0f]; [shapeLayer setLineJoin:kCALineJoinRound]; [shapeLayer setLineDashPattern: [NSArray arrayWithObjects:[NSNumber numberWithInt:5], [NSNumber numberWithInt:5], nil]]; 

现在，如果我只想从点X到点B画一条虚线，我应该如何修改这个代码？

Answer 1

通过首先将path移动到行的起点，然后向某个点添加一个线段来绘制线条：

 CGContextBeginPath(context); CGContextMoveToPoint(context, 10.5f, 10.5f); CGContextAddLineToPoint(context, 20.5f, 20.5f); CGContextClosePath(context); CGContextDrawPath(context, kCGPathFillStroke); 

为了绘制虚线，您需要使用CAShapeLayer

 CAShapeLayer *shapeLayer = [CAShapeLayer layer]; [shapeLayer setBounds:self.bounds]; [shapeLayer setPosition:self.center]; [shapeLayer setFillColor:[[UIColor clearColor] CGColor]]; [shapeLayer setStrokeColor:[[UIColor blackColor] CGColor]]; [shapeLayer setLineWidth:3.0f]; [shapeLayer setLineJoin:kCALineJoinRound]; [shapeLayer setLineDashPattern: [NSArray arrayWithObjects:[NSNumber numberWithInt:10], [NSNumber numberWithInt:5],nil]]; // Setup the path CGMutablePathRef path = CGPathCreateMutable(); CGPathMoveToPoint(path, NULL, 10, 10); CGPathAddLineToPoint(path, NULL, 100,100); [shapeLayer setPath:path]; CGPathRelease(path); [[self layer] addSublayer:shapeLayer]; 

Answer 2

看到：

https://developer.apple.com/library/mac/documentation/graphicsimaging/Reference/CGContext/Reference/reference.html#//apple_ref/c/func/CGContextSetLineDash

 CGFloat dashLengths[] = { 10, 5 }; CGContextSetLineDash(context, 0, dashLengths, 2); 

Answer 3

试试这个代码，它适用于我，

Swift 3.0

 extension UIView { func addDashedLine(strokeColor: UIColor, lineWidth: CGFloat) { backgroundColor = .clear let shapeLayer = CAShapeLayer() shapeLayer.name = "DashedTopLine" shapeLayer.bounds = bounds shapeLayer.position = CGPoint(x: frame.width / 2, y: frame.height / 2) shapeLayer.fillColor = UIColor.clear.cgColor shapeLayer.strokeColor = strokeColor.cgColor shapeLayer.lineWidth = lineWidth shapeLayer.lineJoin = kCALineJoinRound shapeLayer.lineDashPattern = [4, 4] let path = CGMutablePath() path.move(to: CGPoint.zero) path.addLine(to: CGPoint(x: frame.width, y: 0)) shapeLayer.path = path layer.addSublayer(shapeLayer) } } 

Answer 4

迅速，更紧凑：

 func addDashedLine(fromPoint start: CGPoint, toPoint end:CGPoint) { let line = CAShapeLayer() let linePath = UIBezierPath() linePath.moveToPoint(start) linePath.addLineToPoint(end) line.path = linePath.CGPath line.strokeColor = UIColor.redColor().CGColor line.lineWidth = 1 line.lineJoin = kCALineJoinRound line.lineDashPattern = [4, 4] self.layer.addSublayer(line) } 

Answer 5

Swift 2.2

在这里放下这个节省时间..

 extension UIView { func addDashedLine(color: UIColor = UIColor.lightGrayColor()) { layer.sublayers?.filter({ $0.name == "DashedTopLine" }).map({ $0.removeFromSuperlayer() }) self.backgroundColor = UIColor.clearColor() let cgColor = color.CGColor let shapeLayer: CAShapeLayer = CAShapeLayer() let frameSize = self.frame.size let shapeRect = CGRect(x: 0, y: 0, width: frameSize.width, height: frameSize.height) shapeLayer.name = "DashedTopLine" shapeLayer.bounds = shapeRect shapeLayer.position = CGPoint(x: frameSize.width / 2, y: frameSize.height / 2) shapeLayer.fillColor = UIColor.clearColor().CGColor shapeLayer.strokeColor = cgColor shapeLayer.lineWidth = 1 shapeLayer.lineJoin = kCALineJoinRound shapeLayer.lineDashPattern = [4, 4] let path: CGMutablePathRef = CGPathCreateMutable() CGPathMoveToPoint(path, nil, 0, 0) CGPathAddLineToPoint(path, nil, self.frame.width, 0) shapeLayer.path = path self.layer.addSublayer(shapeLayer) } } 

Answer 6

在目标C中使用简化的代码如下所示

  //Dashed line for road CAShapeLayer *dashedLine = [CAShapeLayer layer]; [dashedLine setFrame:CGRectMake(0, 342, 100 , 100)]; // Setup the path CGMutablePathRef thePath = CGPathCreateMutable(); CGPathMoveToPoint(thePath, NULL, 0, 10); CGPathAddLineToPoint(thePath, NULL, screenSize.width,10); dashedLine.path = thePath; CGPathRelease(thePath); [dashedLine setLineDashPattern: [NSArray arrayWithObjects:[NSNumber numberWithFloat:15], nil]]; dashedLine.lineWidth = 1.0f; dashedLine.strokeColor = [[UIColor redcolor] CGColor]]; [self.view.layer addSublayer:dashedLine]; 

Answer 7

 CAShapeLayer *shaplayer = [CAShapeLayer layer];  shaplayer.frame = CGRectMake(100, 100, 100, 100);  [self.view.layer addSublayer:shaplayer];  UIBezierPath *uipath = [UIBezierPath bezierPath];  [uipath moveToPoint:CGPointMake(50, 200)];  [uipath addLineToPoint:CGPointMake(250, 200)];  shaplayer.path = uipath.CGPath;  shaplayer.strokeColor = [UIColor redColor].CGColor;  shaplayer.lineDashPattern = @[@4]; 

Answer 8

下面是在UIView（Xamarin iOS）中绘制虚线的代码片段

注意： separatorView是我的UIView，我需要显示为虚线

  public void ShowDottedLine() { var dashedLayer = new CAShapeLayer(); var frameSize = separatorView.Frame.Size; var shapeRect = new CGRect(0, 0, frameSize.Width, frameSize.Height); dashedLayer.Bounds = shapeRect; dashedLayer.Position = new CGPoint(frameSize.Width / 2, frameSize.Height / 2); dashedLayer.FillColor = UIColor.Clear.CGColor; dashedLayer.StrokeColor = ColorUtils.ColorWithHex(ColorConstants.DarkBlue).CGColor; dashedLayer.LineWidth = 2; dashedLayer.LineJoin = CAShapeLayer.JoinRound; NSNumber[] patternArray = {5,5}; dashedLayer.LineDashPattern = Array; var path = new CGPath(); path.MoveToPoint(CGPoint.Empty); path.AddLineToPoint(new CGPoint(frameSize.Width, 0)); dashedLayer.Path = path; separatorView.Layer.AddSublayer(dashedLayer); }