IOS:OC--通知传值

1:
新建两个类都是继承自 UIViewController，取名为“FirstViewController"和
"SecondViewController"

AppDelegate.m
将 FirstViewController作为根视图控制器
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
self.window.rootViewController = [[UINavigationController alloc] initWithRootViewController:[FirstViewController new]];
self.window.backgroundColor = [UIColor yellowColor];
[self.window makeKeyAndVisible];

FirstViewController.m 导入头文件#import "SecondViewController.h"

• (void)viewDidLoad {
  [super viewDidLoad];
  // Do any additional setup after loading the view.
  self.view.backgroundColor=[UIColor yellowColor];
  [self creatUI];

  //第二步:谁接受消息谁注册通知（注册监听者）
  //注册监听者
  //addObserver:监听者 ,一般都是控制器本身去监听通知
  //selector：当监听到通知中心发送的通知时，执行的方法
  //name：当通知中心的名字，要和发送通知对象的名字一致
  //object
  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(ChangeTextFtext:) name:@"ChangeValue" object:nil];

}
//实现通知方法
-(void)ChangeTextFtext:(NSNotification *)notifition{

//获取通知的内容
NSDictionary * dic = notifition.userInfo;
NSLog(@"%@",dic);
self.field.text = dic[@"Data"];

}
-(void)creatUI{

self.field = [[UITextField alloc]initWithFrame:CGRectMake(0, 100, self.view.frame.size.width, 30) ];
self.field.backgroundColor = [UIColor whiteColor];
[self.view addSubview:self.field];

UIButton * pushbutton =[UIButton buttonWithType:UIButtonTypeSystem];
pushbutton.frame = CGRectMake(0, 140, self.view.frame.size.width, 30);
[pushbutton setTitle:@"Push" forState:(UIControlStateNormal)];
[pushbutton addTarget:self action:@selector(PushClick:) forControlEvents:(UIControlEventTouchUpInside)];
[self.view addSubview:pushbutton];

}
-(void)PushClick:(UIButton *)sender{

SecondViewController * secondVC = [SecondViewController new];
//跳转:
[self.navigationController pushViewController:secondVC animated:YES];

}
/*
通知传值：
1.需要发送通知的物体
2.接收者：谁监听谁接收（注册通知--》name前后一定要一样）
3.实现通知内部方法，并实现传值
4.消息发送完毕，移除监听者
*/

SecondViewController.m：
导入文件#import "FirstViewController.h"

• (void)viewDidLoad {
  [super viewDidLoad];
  // Do any additional setup after loading the view.

  self.view.backgroundColor = [UIColor cyanColor];

  self.field = [[UITextField alloc]initWithFrame:CGRectMake(0, 100, self.view.frame.size.width, 30) ];
  self.field.backgroundColor = [UIColor whiteColor];
  [self.view addSubview:self.field];

  UIButton * popbutton =[UIButton buttonWithType:UIButtonTypeSystem];
  popbutton.frame = CGRectMake(0, 140, self.view.frame.size.width, 30);
  [popbutton setTitle:@"Pop" forState:(UIControlStateNormal)];
  [popbutton addTarget:self action:@selector(PopClick:) forControlEvents:(UIControlEventTouchUpInside)];
  [self.view addSubview:popbutton];

}
-(void)PopClick:(UIButton *)sender{

//发送通知：    单例default\share
//postNotificationName通知中心名字   object接收对象  userInfo携带的参数


[[NSNotificationCenter defaultCenter]postNotificationName:@"ChangeValue" object:nil userInfo:@{@"Data":self.field.text}];

// FirstViewController * firstVC = [FirstViewController new];
//跳转:
[self.navigationController popViewControllerAnimated:YES];

}