ios 判断当前设备

 if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)    {        CGSize result = [[UIScreen mainScreen] bounds].size;                if(result.height == 480.f)        {            return @"ViewController";        }        else        {            return @"ViewController-iPhone5";        }    }    return @"ViewController-iPad";