Method Swizzle

RNSwizzle.m

//  
//  RNSwizzle.m  
//  MethodSwizzle  
  
  
#import "RNSwizzle.h"  
#import <objc/runtime.h>  
@implementation NSObject (RNSwizzle)  
  
  
+ (IMP)swizzleSelector:(SEL)origSelector   
               withIMP:(IMP)newIMP {  
  Class class = [self class];  
  Method origMethod = class_getInstanceMethod(class,  
                                              origSelector);  
  IMP origIMP = method_getImplementation(origMethod);  
    
  if(!class_addMethod(self, origSelector, newIMP,  
                      method_getTypeEncoding(origMethod)))  
  {  
    method_setImplementation(origMethod, newIMP);  
  }  
    
  return origIMP;  
}  
@end