1、定義C函數：

void dynamicMethodIMP(id self, SEL _cmd)

{

NSLog(@"蝸牛也瘋狂");

}

2、重寫函數+(BOOL)resolveInstanceMethod:(SEL)sel

+(BOOL)resolveInstanceMethod:(SEL)sel

{

class_addMethod([self class], sel, (IMP)dynamicMethodIMP, "v@:");

return [super resolveInstanceMethod:sel];

}

3、使用：

SEL select = NSSelectorFromString(@"resolveThisMethodDynamically");

[class resolveInstanceMethod:select];

[[class instance] performSelector:select];