import "AppDelegate.h"

import "FirstViewController.h"

@interface AppDelegate ()

@end

@implementation AppDelegate

• (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
  self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
  // Override point for customization after application launch.
  self.window.backgroundColor = [UIColor whiteColor];
  [self.window makeKeyAndVisible];

  FirstViewController *firstVC = [[FirstViewController alloc]init];
  UINavigationController *navC = [[UINavigationController alloc]initWithRootViewController:firstVC];
  [self.window setRootViewController:navC];
  return YES;
  }

---

import "FirstViewController.h"

import "SecondViewController.h"

@interface FirstViewController ()

@end

@implementation FirstViewController

• (void)viewDidLoad {
  [super viewDidLoad];
  // 设置标题
  self.navigationItem.title = @"FirstVC";
  // 设置导航条右侧按钮
  UIBarButtonItem *rightBtnItem = [[UIBarButtonItem alloc]initWithTitle:@"下一步" style:UIBarButtonItemStyleDone target:self action:@selector(rightBarButtonAction:)];
  self.navigationItem.rightBarButtonItem = rightBtnItem;

  // 设置导航左侧按钮（点击后回收键盘）
  UIBarButtonItem *leftBtnItem = [[UIBarButtonItem alloc]initWithTitle:@"回收键盘" style:UIBarButtonItemStyleDone target:self action:@selector(endEditingAction)];
  leftBtnItem.tag = 2000;
  self.navigationItem.leftBarButtonItem = leftBtnItem;

  // 初始化一个textField文本输入框
  UITextField *userTextField = [[UITextField alloc]initWithFrame:CGRectMake(100, 100, 200, 40)];
  userTextField.borderStyle = UITextBorderStyleBezel;
  userTextField.textAlignment = NSTextAlignmentCenter;
  userTextField.placeholder = @"请输入文字";
  userTextField.tag = 1000;
  [self.view addSubview:userTextField];

  UITextField *pwsTextField = [[UITextField alloc]initWithFrame:CGRectMake(100, 180, 200, 40)];
  pwsTextField.borderStyle = UITextBorderStyleBezel;
  pwsTextField.textAlignment = NSTextAlignmentCenter;
  pwsTextField.placeholder = @"密 码";
  pwsTextField.keyboardType = UIKeyboardTypeNumberPad;
  pwsTextField.secureTextEntry = YES;
  pwsTextField.tag = 1001;
  [self.view addSubview:pwsTextField];

  UITextField *yanZhengTextField = [[UITextField alloc]initWithFrame:CGRectMake(100, 260, 200, 40)];
  

  yanZhengTextField.borderStyle = UITextBorderStyleBezel;
  yanZhengTextField.textAlignment = NSTextAlignmentCenter;
  yanZhengTextField.keyboardType = UIKeyboardTypeNumberPad;
  pwsTextField.keyboardType = UIKeyboardTypeNumberPad;
  yanZhengTextField.placeholder = @"请输入验证码";
  yanZhengTextField.tag = 1002;
  [self.view addSubview:yanZhengTextField];

  }
  // 导航条右侧按钮回调方法，具体实现为推送到下个界面
  -(void)rightBarButtonAction:(UIBarButtonItem*)sender{
  SecondViewController *secondVC = [[SecondViewController alloc]init];
  // 将文本输入框的值赋值secondVC的属性
  UITextField userTextField = (UITextField)[self.view viewWithTag:1000];// textField为局部变量
  secondVC.userStr = userTextField.text;
  UITextField pwsTextField = (UITextField)[self.view viewWithTag:1001];
  secondVC.pwsStr = pwsTextField.text;
  UITextField yanZhengTextField = (UITextField)[self.view viewWithTag:1002];
  secondVC.yanZhengStr = yanZhengTextField.text;

  [self.navigationController pushViewController:secondVC animated:YES];
  }

// 导航条左侧按钮回调方法
-(void)endEditingAction{
[self.view endEditing:YES];
}

• (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
  }

---

import <UIKit/UIKit.h>

@interface SecondViewController : UIViewController

@property (nonatomic ,retain)NSString *userStr; // 用来接受第一个界面传过来的内容
@property (nonatomic ,retain)NSString *pwsStr;
@property (nonatomic ,retain)NSString *yanZhengStr;

@end

import "SecondViewController.h"

import "ThirdViewController.h"

@interface SecondViewController ()<ThirdViewControllerDelegate>

@end

@implementation SecondViewController

// thirdVC的代理方法，作用为，将thirdVC上的值传递到当前的视图控制器
-(void)passValueWithDic:(NSDictionary *)valueDic{
NSLog(@"dic_______%@",valueDic);
UILabel userLabel = (UILabel)[self.view viewWithTag:5000];
userLabel.text = [valueDic valueForKey:@"name"];

UILabel *pswLabel = (UILabel*)[self.view viewWithTag:5001];
pswLabel.text = [valueDic valueForKey:@"pws"];

UILabel *yanZhengLabel = [self.view viewWithTag:5002];
yanZhengLabel.text = [valueDic valueForKey:@"yanZheng"];

}

• (void)viewDidLoad {
  [super viewDidLoad];
  self.navigationItem.title = @"SecondVC";
  // 声明一个label，用来显示首个界面传过来的内容
  UILabel *userLabel = [[UILabel alloc]initWithFrame:CGRectMake(100, 100, 200, 40)];
  // label显示的内容为从首个界面传过来的值
  userLabel.text = self.userStr;
  userLabel.tag = 5000;
  [self.view addSubview:userLabel];

  UILabel *pwsLabel = [[UILabel alloc]initWithFrame:CGRectMake(100, 180, 200, 40)];
  pwsLabel.text = self.pwsStr;
  pwsLabel.tag = 5001;
  [self.view addSubview:pwsLabel];

  UILabel *yanZhengLabel = [[UILabel alloc]initWithFrame:CGRectMake(100, 260, 200, 40)];
  yanZhengLabel.text = self.yanZhengStr;
  yanZhengLabel.tag = 5002;
  [self.view addSubview:yanZhengLabel];

  // 设置导航条右侧按钮，点击跳转到下个界面（ThirdViewController）
  UIBarButtonItem *rightBtnItem = [[UIBarButtonItem alloc]initWithTitle:@"下一步" style:UIBarButtonItemStyleDone target:self action:@selector(rightBarButtonAction:)];
  self.navigationItem.rightBarButtonItem = rightBtnItem;
  }

// 导航条右侧按钮回调方法，点击跳转到下个界面（ThirdViewController）
-(void)rightBarButtonAction:(UIBarButtonItem*)sender{
ThirdViewController *thirdVC = [[ThirdViewController alloc]init];
// 指定代理 {self:在类方法（加号方法）中指的是本类，在对象方法（减号方法）中指的是该类的一个对象}
thirdVC.delegate = self;
[self.navigationController pushViewController:thirdVC animated:YES];
}

• (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
  }
  @end

---

import <UIKit/UIKit.h>

@protocol ThirdViewControllerDelegate <NSObject>

// 该方法的参数就是要传递的值
-(void)passValueWithDic:(NSDictionary*)valueDic;

@end

@interface ThirdViewController : UIViewController

@property (nonatomic ,assign)id<ThirdViewControllerDelegate> delegate;

@end

import "ThirdViewController.h"

@interface ThirdViewController ()

@end

@implementation ThirdViewController

• (void)viewDidLoad {
  [super viewDidLoad];
  self.navigationItem.title = @"ThirdVC";

  for (int i = 0; i < 3; i++) {
  UITextField textField = [[UITextField alloc]initWithFrame:CGRectMake(100, 100+100i, 200, 40)];
  textField.borderStyle = UITextBorderStyleBezel;
  textField.textAlignment = NSTextAlignmentCenter;
  textField.placeholder = @"请输入文字";
  textField.tag = 1000+i;
  [self.view addSubview:textField];
  }

  // 因为需要向前传值，所以需要捕获点击按钮的事件，所以需要重新定义leftBarButtonItem
  UIBarButtonItem *leftBtnItem = [[UIBarButtonItem alloc]initWithTitle:@"返回" style:UIBarButtonItemStyleDone target:self action:@selector(backBtnAction:)];
  leftBtnItem.tag = 2000;
  self.navigationItem.leftBarButtonItem = leftBtnItem;

}
// 返回按钮的点击事件
-(void)backBtnAction:(UIBarButtonItem*)sender{
UITextField nameTextField = (UITextField)[self.view viewWithTag:1000];
UITextField pwsTextField = (UITextField)[self.view viewWithTag:1001];
UITextField yanZhengTextField = (UITextField)[self.view viewWithTag:1002];

/*
 if条件判断中
 第一步：先判断是否指定了代理
 第二步：respondsToSelector该方法的返回值为BOOL类型。该方法会从指定的代理类中（这里我们的代理类就是SecondViewController）找寻方法选择器重中方法的实现，如果没有实现该协议方法，就返回NO，如果实现，就返回YES
 self.delegate : 指定哪个类为代理，它就是代理类的一个对象，在这里它指的就是 SecondViewController这个类的一个对象那，我们在SecondViewController也实现了passValueWithDic:这个方法，所以我们可以调用此方法
 （self.delegate = SecondViewController）
      */

if (self.delegate && [self.delegate respondsToSelector:@selector(passValueWithDic:)]) {
[self.delegate passValueWithDic:@{@"name":nameTextField.text,@"pws":pwsTextField.text,@"yanZheng":yanZhengTextField.text}];
}

[self.navigationController popViewControllerAnimated:YES];

}

• (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
  }
  @end