iOS开发绘制虚线的方法
方法一：通过Quartz 2D 在 UIView drawRect:方法进行绘制虚线
- (void)drawRect:(CGRect)rect {// 可以通过 setNeedsDisplay 方法调用 drawRect:
// Drawing code
CGContextRef context =UIGraphicsGetCurrentContext();
// 设置线条的样式
CGContextSetLineCap(context, kCGLineCapRound);
// 绘制线的宽度
CGContextSetLineWidth(context,3.0);
// 线的颜色
CGContextSetStrokeColorWithColor(context, [UIColororangeColor].CGColor);
// 开始绘制
CGContextBeginPath(context);
// 设置虚线绘制起点
CGContextMoveToPoint(context,10.0,20.0);
// lengths的值｛10,10｝表示先绘制10个点，再跳过10个点，如此反复
CGFloat lengths[] = {10,10};
// 虚线的起始点
CGContextSetLineDash(context,0, lengths,2);
// 绘制虚线的终点
CGContextAddLineToPoint(context,310.0,20.0);
// 绘制
CGContextStrokePath(context);
// 关闭图像
CGContextClosePath(context);
}
方法二:通过 Quartz 2D 在 UIImageView 绘制虚线
/**
* 通过 Quartz 2D 在 UIImageView 绘制虚线
*
* param imageView 传入要绘制成虚线的imageView
* return
*/
- (UIImage *)drawLineOfDashByImageView:(UIImageView *)imageView {
// 开始划线 划线的frame
UIGraphicsBeginImageContext(imageView.frame.size);
[imageView.image drawInRect:CGRectMake(0,0, imageView.frame.size.width, imageView.frame.size.height)];
// 获取上下文
CGContextRef line = UIGraphicsGetCurrentContext();
// 设置线条终点的形状
CGContextSetLineCap(line, kCGLineCapRound);
// 设置虚线的长度 和 间距
CGFloat lengths[] = {5,5};
CGContextSetStrokeColorWithColor(line, [UIColor greenColor].CGColor);
// 开始绘制虚线
CGContextSetLineDash(line,0, lengths,2);
CGContextMoveToPoint(line,0.0,2.0);
CGContextAddLineToPoint(line,300,2.0);
CGContextStrokePath(line);
// UIGraphicsGetImageFromCurrentImageContext()返回的就是image
return UIGraphicsGetImageFromCurrentImageContext();
}
方法三：通过CAShapeLayer 方式绘制虚线
/**
** lineView: 需要绘制成虚线的view
** lineLength: 虚线的宽度
** lineSpacing: 虚线的间距
** lineColor: 虚线的颜色
**/
- (void)drawDashLine:(UIView *)lineView lineLength:(int)lineLength lineSpacing:(int)lineSpacing lineColor:(UIColor *)lineColor
{
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
[shapeLayer setBounds:lineView.bounds];
[shapeLayer setPosition:CGPointMake(CGRectGetWidth(lineView.frame) / 2, CGRectGetHeight(lineView.frame))];
[shapeLayer setFillColor:[UIColor clearColor].CGColor];
// 设置虚线颜色
[shapeLayer setStrokeColor:lineColor.CGColor];
// 设置虚线宽度
[shapeLayer setLineWidth:CGRectGetHeight(lineView.frame)];
[shapeLayer setLineJoin:kCALineJoinRound];
// 设置线宽，线间距
[shapeLayer setLineDashPattern:[NSArray arrayWithObjects:[NSNumber numberWithInt:lineLength], [NSNumber numberWithInt:lineSpacing], nil]];
// 设置路径
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, 0, 0);
CGPathAddLineToPoint(path, NULL,CGRectGetWidth(lineView.frame), 0);
[shapeLayer setPath:path];
CGPathRelease(path);
// 把绘制好的虚线添加上来
[lineView.layer addSublayer:shapeLayer];
}
