UIView+StringTagAdditions.h

#import <UIKit/UIKit.h>

@interface UIView (StringTagAdditions)
@property (nonatomic, copy) NSString *stringTag;
@end

UIView+StringTagAdditions.m

#import "UIView+StringTagAdditions.h"
#import <objc/runtime.h>

@implementation UIView (StringTagAdditions)

static NSString *kStringTagKey = @"StringTagKey";
- (NSString *)stringTag
{
    return (NSString*) objc_getAssociatedObject(self, CFBridgingRetain(kStringTagKey));
}
- (void)setStringTag:(NSString *)stringTag
{
    objc_setAssociatedObject(self, CFBridgingRetain(kStringTagKey), stringTag, OBJC_ASSOCIATION_COPY_NONATOMIC);
}

@end