绘制虚线

 CAShapeLayer *shapeLayer = [CAShapeLayer layer];

    [shapeLayersetBounds:self.view.bounds];

    [shapeLayersetPosition:self.view.center];

    [shapeLayersetFillColor:[[UIColor clearColor] CGColor]];

    // 设置虚线颜色为blackColor

    [shapeLayersetStrokeColor:[[UIColor colorWithRed:223/255.0 green:223/255.0 blue:223/255.0 alpha:1.0f] CGColor]];

    // 3.0f设置虚线的宽度

    [shapeLayersetLineWidth:1.0f];

    [shapeLayersetLineJoin:kCALineJoinRound];

    // 3=线的宽度 1=每条线的间距

    [shapeLayersetLineDashPattern:

     [NSArray arrayWithObjects:[NSNumber numberWithInt:3],

      [NSNumbernumberWithInt:1],nil]];

    // Setup the path

    CGMutablePathRef path = CGPathCreateMutable();

    CGPathMoveToPoint(path, NULL, 0, 89);

    CGPathAddLineToPoint(path, NULL, 320,89);

    [shapeLayersetPath:path];

    CGPathRelease(path);

    // 可以把self改成任何你想要的UIView, 下图演示就是放到UITableViewCell中的

    [[self.viewlayer]addSublayer:shapeLayer];