ios通知-kvo

// KVC: Key Value Coding, 常见作用：给模型属性赋值
    // KVO: Key Value Observing, 常用作用：监听模型属性值的改变

 //
 //  ViewController.m
 //  11-通知、KVO、代理
 //
 //  Created by xiaomage on 15/6/6.
 //  Copyright (c) 2015年 xiaomage. All rights reserved.
 //

 #import "ViewController.h"
 #import "XMGPerson.h"

 @interface ViewController ()
 @property (nonatomic, strong) XMGPerson *p1;
 @property (nonatomic, strong) XMGPerson *p2;
 @property (nonatomic, strong) XMGPerson *p3;
 @end

 @implementation ViewController

 - (void)viewDidLoad {
     [super viewDidLoad];

 //    self.p1 = [[XMGPerson alloc] init];
 //    self.p1.name = @"p1";
 //
 //    self.p2 = [[XMGPerson alloc] init];
 //    self.p2.name = @"p2";
 //
 //    self.p3 = [[XMGPerson alloc] init];
 //    self.p3.name = @"p3";
 //    同一个通知TestNotification可以被多个对象person监听
 // 当收到TestNotification通知就调用self.p1的test方法
 //    [[NSNotificationCenter defaultCenter] addObserver:self.p1 selector:@selector(test) name:@"TestNotification" object:nil];
 //    [[NSNotificationCenter defaultCenter] addObserver:self.p2 selector:@selector(test) name:@"TestNotification" object:nil];
 //    [[NSNotificationCenter defaultCenter] addObserver:self.p3 selector:@selector(test) name:@"TestNotification" object:nil];
 //    多个对象可以发出同一个通知
 //对象@“123”发出TestNotification通知
 //    [[NSNotificationCenter defaultCenter] postNotificationName:@"TestNotification" object:@"123"];
 //    [[NSNotificationCenter defaultCenter] postNotificationName:@"TestNotification" object:@"345"];

     // KVC: Key Value Coding, 常见作用：给模型属性赋值
     // KVO: Key Value Observing, 常用作用：监听模型属性值的改变

     self.p1 = [[XMGPerson alloc] init];
     self.p1.name = @"p1";
     //self.p1 监听属性 name的改变，NSKeyValueObservingOptionOld表示监听方法中的NSDictional显示旧值
     [self.p1 addObserver:self forKeyPath:@"name" options: NSKeyValueObservingOptionOld context:nil];

     self.p1.name = @"pppp1";
 }
 //所有的通知监听 都要在dealloc销毁时removeObserver
 - (void)dealloc
 {
     [self.p1 removeObserver:self forKeyPath:@"name"];
 }

 #pragma mark - KVO监听方法
 /**
  * 当监听到object的keyPath属性发生了改变
 *这个方法是NSObject的类扩展方法，用来监听对象属性改变
 *keyPath属性名称如name
 *id 对象 如self.p1
 *change 记录改变前后的值
  */
 - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
 {
     NSLog(@"监听到%@对象的%@属性发生了改变， %@", object, keyPath, change);
 }

 @end