PrivateClassesMethodSwizzling.m

#import <objc/runtime.h>
#import <UIKit/UIKit.h>

#import "NSObject+Swizzling.h"

@implementation NSObject (Swizzling)

+ (void)load {
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        Class class = objc_getClass("UITabBarButton");
        NSString *selectorString = @"initWithImage:selectedImage:label:withInsets:tabBar:";
        
        Method originalMethod = class_getInstanceMethod(class, NSSelectorFromString(selectorString));
        Method swizzledMethod = class_getInstanceMethod(class, NSSelectorFromString([@"swizzled_" stringByAppendingString:selectorString]));
        
        method_exchangeImplementations(originalMethod, swizzledMethod);
    });
}

- (id)swizzled_initWithImage:(id)image selectedImage:(id)selectedImage label:(id)label withInsets:(UIEdgeInsets)insets tabBar:(id)tabBar {
    return [self swizzled_initWithImage:image selectedImage:selectedImage label:label withInsets:insets tabBar:tabBar];
}

@end