Swizzling valueForKey: and objectForKey:

gistfile1.m

#import <objc/runtime.h>

@implementation NSDictionary (Swizzled)

static void swizzInstance(Class class, SEL originalSel, SEL newSel)
{
    Method origMethod = class_getInstanceMethod(class, originalSel);
    Method newMethod = class_getInstanceMethod(class, newSel);
    
    method_exchangeImplementations(origMethod, newMethod);
}

- (id)zzz_valueForKey:(NSString *)key
{
    return [self zzz_valueForKey:key];
}

- (id)zzz_objectForKey:(NSString *)key
{
    return [self zzz_objectForKey:key];
}


+ (void)swizz
{
    swizzInstance(NSClassFromString(@"__NSDictionaryM"),@selector(objectForKey:),@selector(zzz_objectForKey:));
    
    swizzInstance(NSClassFromString(@"__NSDictionaryM"),@selector(valueForKey:),@selector(zzz_valueForKey:));
}

@end

It seems that objectForKey: not working. I have tried for many times.