UIView+Border.m

// Source:

@implementation UIView (Border)

- (void)addBorder:(UIRectEdge)edge color:(UIColor *)color thickness:(CGFloat)thickness
{
    if ((UIRectEdgeTop & edge) == UIRectEdgeTop) {
        [self.layer addSublayer:[self borderLayerMake:CGRectMake(0, 0, CGRectGetWidth(self.frame), thickness) color:color]];
    }
    if ((UIRectEdgeBottom & edge) == UIRectEdgeBottom) {
        [self.layer addSublayer:[self borderLayerMake:CGRectMake(0, CGRectGetHeight(self.frame) - thickness, CGRectGetWidth(self.frame), thickness) color:color]];
    }
    if ((UIRectEdgeLeft & edge) == UIRectEdgeLeft) {
        [self.layer addSublayer:[self borderLayerMake:CGRectMake(0, 0, thickness, CGRectGetHeight(self.frame)) color:color]];
    }
    if ((UIRectEdgeRight & edge) == UIRectEdgeRight) {
        [self.layer addSublayer:[self borderLayerMake:CGRectMake(CGRectGetWidth(self.frame) - thickness, 0, thickness, CGRectGetHeight(self.frame)) color:color]];
    }
}

- (CALayer *)borderLayerMake:(CGRect)rect color:(UIColor *)color {
    CALayer *border = [CALayer layer];
    border.backgroundColor = color.CGColor;
    border.frame = rect;
    return border;
}

@end

// Sample:

@implementation XXView

[self.label addBorder:UIRectEdgeTop | UIRectEdgeBottom color:[UIColor lightGrayColor] thickness:1.0f / [UIScreen mainScreen].scale];

@end