首先學習NSObject 

//
//  ViewController.m
//  localization
//
//  Created by City--Online on 15/5/15.
//  Copyright (c) 2015年 XQB. All rights reserved.
//
 
#import "ViewController.h"
 
@interface ViewController ()
 
@end
 
@implementation ViewController
 
- (void)viewDidLoad {
    [super viewDidLoad];
    //NSObject內包含 alloc、init方法
    NSObject *obj=[[NSObject alloc]init];
    //父類
    NSLog(@"superClass: %@",[obj superclass]);
    //當前類
    NSLog(@"Class: %@",[obj class]);
    //copy
    NSLog(@"copy: %@",[NSObject copy]);
    //hash
    NSLog(@"hash:%ld",[obj hash]);
    //description
    NSLog(@"description: %@",[obj description]);
    //debugDescription
    NSLog(@"debugDescription: %@",[obj debugDescription]);
//    - (id)performSelector:(SEL)aSelector;
//    - (id)performSelector:(SEL)aSelector withObject:(id)object;
//    - (id)performSelector:(SEL)aSelector withObject:(id)object1 withObject:(id)object2;
    [self performSelector:@selector(test)];
    //isProxy
    BOOL isProxy=[obj isProxy];
    NSLog(@"isProxy: %d",isProxy);
     
//    - (BOOL)isKindOfClass:(Class)aClass;
//    - (BOOL)isMemberOfClass:(Class)aClass;
//    - (BOOL)conformsToProtocol:(Protocol *)aProtocol;
//    - (BOOL)respondsToSelector:(SEL)aSelector;
     
    //來確定一個對象是否是一個類的成員，或者是派生自該類的成員
    BOOL isKindOfClass=[obj isKindOfClass:[NSObject class]];
    NSLog(@"isKindOfClass:%d",isKindOfClass);
     
    //只能確定一個對象是否是當前類的成員
    BOOL isMemberOfClass=[obj isMemberOfClass:[NSObject class]];
    NSLog(@"isMemberOfClass:%d",isMemberOfClass);
     
    //是用來檢查對象是否實現了指定協議類的方法
    BOOL IsConformsToProtocol=[obj conformsToProtocol:@protocol(UIApplicationDelegate)];
    NSLog(@"IsConformsToProtocol: %d",IsConformsToProtocol);
     
    //用來判斷是否有以某個名字命名的方法(被封裝在一個selector的對象里傳遞)
    BOOL isRespondsToSelector=[obj respondsToSelector:@selector(hash)];
    NSLog(@"isRespondsToSelector:%d",isRespondsToSelector);
     
    // selector 用來判斷實例是否有以某個名字命名的方法. 和上面一個不同之處在于, 前面這個方法可以用在實例和類上，而此方法只能用在類上
    BOOL isInstancesRespondToSelector=[NSObject instancesRespondToSelector:@selector(hash)];
    NSLog(@"isInstancesRespondToSelector:%d",isInstancesRespondToSelector);
     
    
}
-(void)test
{
    NSLog(@"test");
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
 
@end