UIImageView*imageView1 = [[UIImageViewalloc]initWithFrame:CGRectMake(0,100,320,20)];
[self.viewaddSubview:imageView1];
UIGraphicsBeginImageContext(imageView1.frame.size);//开始画线
[imageView1.imagedrawInRect:CGRectMake(0,0, imageView1.frame.size.width, imageView1.frame.size.height)];
CGContextSetLineCap(UIGraphicsGetCurrentContext(),kCGLineCapRound);//设置线条终点形状
CGFloatlengths[] = {10,5};
CGContextRefline =UIGraphicsGetCurrentContext();
CGContextSetStrokeColorWithColor(line, [UIColorredColor].CGColor);
CGContextSetLineDash(line,0, lengths,2);//画虚线
CGContextMoveToPoint(line,0.0,20.0);//开始画线
CGContextAddLineToPoint(line,310.0,20.0);
CGContextStrokePath(line);
imageView1.image=UIGraphicsGetImageFromCurrentImageContext();