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这就需要用到属性传值、block传值
那么第一个视图控制器如何获的第二个视图控制器的部分信息
例如：第一个界面中的lable显示第二个界面textField中的文本
这就需要使用代理传值
页面间传值有八大传值方式，下面我们就简单介绍下页面间传值的几种方式：
第二个界面中的lable显示第一个界面textField中的文本
首先我们建立一个RootViewControllers和一个DetailViewControllers，在DetailViewControllers中声明一个textString属性，用于接收传过来的字符串，
同时创建一个Lable用来显示传过的字符串
在RootViewControllers上引入DetailViewControllers同时声明一个textField属性用来输入字符串
然后在RootViewControllers上我们创建并添加一个button，当点击button时响应相应方法进行视图间的切换完成视图间的传值
block传值也是从第二个界面给第一个界面传值
首先我们在DetailViewcontrollers的.h文件中，属性
在RootViewControllers的.m文件中，其他不变，在button的响应方法里我们为block属性赋值完成block传值
RootViewControllers页面push到DetailViewControllers页面，如果DetailViewControllers页面的信息想回传（回调）到RootViewControllers页面，用代理传值，其中DetailViewControllers定义协议和声明代理，RootViewControllers确认并实现代理，RootViewControllers作为DetailViewControllers的代理
首先在DetailViewControllers.h文件中我们创建协议方法
在DetailViewControllers的.m中我们判定代理对象存在时，为其绑定相应方法
RootViewControllers的.m文件中我们指定代理并让其执行代理的方法
AppStatus.h 创建一个单例类 AppStatus
1 #import <Foundation/Foundation.h>
2
3 @interface AppStatus : NSObject
4 {
5 NSString *_contextStr;
6 }
7
8 @property(nonatomic,retain)NSString *contextStr;
9
10 +(AppStatus *)shareInstance;
11
12 @end
AppStatus.m
1 #import "AppStatus.h"
2
3 @implementation AppStatus
4
5 @synthesize contextStr = _contextStr;
6
7 static AppStatus *_instance = nil;
8
9 +(AppStatus *)shareInstance
10 {
11 if (_instance == nil)
12 {
13 _instance = [[super alloc]init];
14 }
15 return _instance;
16 }
17
18 -(id)init
19 {
20 if (self = [super init])
21 {
22
23 }
24 return self;
25 }
26
27 -(void)dealloc
28 {
29 [super dealloc];
30 }
31
32 @end
RootViewController.h
1 #import "RootViewController.h"
2 #import "DetailViewController.h"
3 #import "AppStatus.h"
4
5 @interface RootViewController ()
6
7 @end
8
9 @implementation RootViewController
10
11 -(void)loadView
12 {
13 //核心代码
14 UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
15 btn.frame = CGRectMake(0, 0, 100, 30);
16 [btn setTitle:@"Push" forState:0];
17 [btn addTarget:self action:@selector(pushAction:) forControlEvents:UIControlEventTouchUpInside];
18 [self.view addSubview:btn];
19 }
20
21 -(void)pushAction:(id)sender
22 {
23 tf = (UITextField *)[self.view viewWithTag:1000];
24
25 //单例传值 将要传递的信息存入单例中（共享中）
26 // [[AppStatus shareInstance]setContextStr:tf.text]; 跟下面这种写法是等价的
27 [AppStatus shareInstance].contextStr = tf.text;
28 //导航push到下一个页面
29 //pushViewController 入栈引用计数+1，且控制权归系统
30 DetailViewController *detailViewController = [[DetailViewController alloc]init];
31
32 //导航push到下一个页面
33 [self.navigationController pushViewController:detailViewController animated:YES];
34 [detailViewController release];
35 }
36
37 @end
DetailViewController.h
1 #import <UIKit/UIKit.h>
2 @protocol ChangeDelegate;//通知编译器有此代理
3
4 @interface DetailViewController : UIViewController
5 {
6 UITextField *textField;
7 }
8
9 @end
DetailViewController.m
1 #import "DetailViewController.h"
2 #import "AppStatus.h"
3
4 @interface DetailViewController ()
5
6 @end
7
8 @implementation DetailViewController
9
10 @synthesize naviTitle = _naviTitle;
11
12 -(void)loadView
13 {
14 self.view = [[[UIView alloc]initWithFrame:CGRectMake(0, 0, 320, 480)]autorelease];
15
16 //单例
17 self.title = [AppStatus shareInstance].contextStr;
18 textField = [[UITextField alloc]initWithFrame:CGRectMake(100, 100, 150, 30)];
19 textField.borderStyle = UITextBorderStyleLine;
20 [self.view addSubview:textField];
21 [textField release];
22
23 UIBarButtonItem *doneItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDonetarget:self action:@selector(doneAction:)];
24 self.navigationItem.rightBarButtonItem = doneItem;
25 [doneItem release];
26 }
27
28 //这个方法是执行多遍的 相当于刷新view
29 -(void)viewWillAppear:(BOOL)animated
30 {
31 [super viewWillAppear:animated];
32 tf = (UITextField *)[self.view viewWithTag:1000];
33 tf.text = [AppStatus shareInstance].contextStr;
34 }
35
36 //pop回前一个页面
37 -(void)doneAction:(id)sender
38 {
39 //单例传值
40 [AppStatus shareInstance].contextStr = textField.text;
41 [self.navigationController popToRootViewControllerAnimated:YES];
42 }
谁要监听值的变化，谁就注册通知 特别要注意，通知的接受者必须存在这一先决条件
A页面RootViewController.h
1 #import <UIKit/UIKit.h>
2 #import "DetailViewController.h"
3 @interface RootViewController : UIViewController<ChangeDelegate>
4 {
5 UITextField *tf;
6 }
7 @end
A页面RootViewController.m
1 #import "IndexViewController.h"
2 #import "DetailViewController.h"
3 #import "AppStatus.h"
4
5 @implementation IndexViewController
6
7 -(void)dealloc
8 {
9 [[NSNotificationCenter defaultCenter] removeObserver:self
10 name:@"CHANGE_TITLE" object:nil];
11 [super dealloc];
12 }
13
14 -(id)init
15 {
16 if (self = [super init])
17 {
18 [[NSNotificationCenter defaultCenter] addObserver:self
19 selector:@selector(change:)
20 name:@"CHANGE_TITLE"
21 object:nil];
22 }
23 return self;
24 }
25
26 -(void)change:(NSNotification *)aNoti
27 {
28 // 通知传值
29 NSDictionary *dic = [aNoti userInfo];
30 NSString *str = [dic valueForKey:@"Info"];
31
32 UITextField *tf = (UITextField *)[self.view viewWithTag:1000];
33 tf.text = str;
34 }
35
36 -(void)viewWillAppear:(BOOL)animated
37 {
38 [super viewWillAppear:animated];
39 /*
40 // 单例传值
41 UITextField *tf = (UITextField *)[self.view viewWithTag:1000];
42 tf.text = [AppStatus shareInstance].contextStr;
43 */
44 }
45
46 @end
DetailViewController.h
1 #import <UIKit/UIKit.h>
2 @protocol ChangeDelegate;//通知编译器有此代理
3
4 @interface DetailViewController : UIViewController
5 {
6 UITextField *textField;
7 }
8 @end
DetailViewController.m
1 #import "DetailViewController.h"
2 #import "AppStatus.h"
3
4 @implementation DetailViewController
5 @synthesize naviTitle = _naviTitle;
6
7 -(void)loadView
8 {
9 UIBarButtonItem *doneItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDonetarget:self action:@selector(doneAction:)];
10 self.navigationItem.rightBarButtonItem = doneItem;
11 [doneItem release];
12 }
13
14 // pop回前一个页面
15 -(void)doneAction:(id)sender
16 {
17 NSDictionary *dic = [NSDictionary dictionaryWithObject:textField.text forKey:@"Info"];
18
19 [[NSNotificationCenter defaultCenter] postNotificationName:@"CHANGE_TITLE" object:nil userInfo:dic];
20
21 [self.navigationController popViewControllerAnimated:YES];
22
23 }
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原文地址：http://www.cnblogs.com/mgla/p/5734523.html
