正向传值均可，反向传值除属性传值不可，其余均可。下面简单介绍：

（一）属性传值

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

（二）Block传值

block传值也是从第一个界面给第二个界面传值

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

（三）代理传值

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

（四）单例传值

单例传值（实现共享）

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 }

（五）通知传值

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