Badge number on a UIButton using MKNumberBadgeView

gistfile1.m

################################
### UIButton+BPBadgeButton.h ###
################################

#import <UIKit/UIKit.h>

@interface UIButton (BPBadgeButton)
@property (nonatomic) NSUInteger badge;
@end

################################
### UIButton+BPBadgeButton.h ###
################################


#import "UIButton+BPBadgeButton.h"
#import "MKNumberBadgeView.h"
#import <objc/runtime.h>

static char const * const badgeKey = "badge";

@interface UIButton ()
-(MKNumberBadgeView *)badgeView;
@end

@implementation UIButton (BPBadgeButton)

-(void)setBadge:(NSUInteger)newBadge
{
    MKNumberBadgeView *badgeView = [self badgeView];
    badgeView.value = newBadge;
    badgeView.frame = CGRectMake(self.frame.size.width-badgeView.badgeSize.width-10,
                                    0,
                                    badgeView.badgeSize.width+10,
                                    self.frame.size.height);
    badgeView.hidden = (newBadge == 0);
}

-(NSUInteger)badge
{
    MKNumberBadgeView *badgeView = [self badgeView];
    return badgeView.value;
}

-(MKNumberBadgeView *)badgeView;
{
    MKNumberBadgeView *badgeView = (MKNumberBadgeView *)objc_getAssociatedObject(self, badgeKey);
    if(!badgeView){
        badgeView = [[MKNumberBadgeView alloc] initWithFrame:CGRectMake(0, 0, 0, 0)];
        [self addSubview:badgeView];
        badgeView.hidden = YES;
        objc_setAssociatedObject(self, badgeKey, badgeView, OBJC_ASSOCIATION_RETAIN);
    }
    return badgeView;
}
@end