iOS 多视图—视图切换之代理Delegate传参切换

步骤：先在iOS平台创建一个工程 ，之后再工程中创建有类（FirstVIewController）
代码实现如下
FirstViewController.h

#import <UIKit/UIKit.h>

//创建协议 声明协议

@protocol PostVslueDelegate <NSObject>

-(void)postValue:(NSString *)info;

@end

@interface FirstViewController : UIViewController<UITextFieldDelegate>

//声明属性

@property(strong,nonatomic)UITextField *textName;

@property(strong,nonatomic)NSString *string;

@property(strong,nonatomic)id<PostVslueDelegate> Delegate;
@end

FirstViewController.m

#import "FirstViewController.h"

@interface FirstViewController ()

@end

@implementation FirstViewController

- (void)viewDidLoad {
[super viewDidLoad];
//设置主屏背景色
self.view.backgroundColor=[UIColor yellowColor];
//创建文本框
self.textName=[[UITextField alloc]initWithFrame:CGRectMake(100, 100, 150, 40)];
self.textName.borderStyle=1;
//指定代理
self.textName.delegate=self;
//传值
self.textName.text=self.string;
[self.view addSubview:self.textName];

}

//实现代理方法

-(BOOL)textFieldShouldReturn:(UITextField *)textField

{
//调用代理方法
if (self.Delegate) {
[self.Delegate postValue:textField.text];
}
//切换页面
[self dismissViewControllerAnimated:YES completion:^{
NSLog(@"切换成功");
}];
//隐藏键盘
if ([textField isFirstResponder]) {
[textField resignFirstResponder];
}
return YES;

}

- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];

}

@end

ViewController.h

#import <UIKit/UIKit.h>

#import "FirstViewController.h"

@interface ViewController : UIViewController<UITextFieldDelegate,PostVslueDelegate>

@property(strong,nonatomic)UITextField *textName;

@property(strong,nonatomic)NSString *string;

@property(strong,nonatomic)UIButton *myButton;

@end

ViewController.m

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
//背景色
self.view.backgroundColor=[UIColor greenColor];
//创建文本框
self.textName=[[UITextField alloc]initWithFrame:CGRectMake(100, 100, 150, 50)];
self.textName.borderStyle=1;
//指定代理
self.textName.delegate=self;
[self.view addSubview:self.textName];

//创建按钮
self.myButton=[[UIButton alloc]initWithFrame:CGRectMake(150, 160, 50, 50)];
self.myButton.backgroundColor=[UIColor redColor];
[self.myButton setTitle:@"Next" forState:UIControlStateNormal];
[self.myButton addTarget:self action:@selector(nextPage) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:self.myButton];

}

-(void)nextPage

{
FirstViewController *firstVC=[[FirstViewController alloc]init];
//正传参值
firstVC.string=self.textName.text;
//指定代理
firstVC.Delegate=self;

//切换视图
[self presentViewController:firstVC animated:YES completion:^{
NSLog(@"切换成功");

}];

}

//协议方法

-(void)postValue:(NSString *)info

{
//功能：反传参值
self.textName.text=info;

}

//代理方法

-(BOOL)textFieldShouldReturn:(UITextField *)textField

{
//隐藏键盘
if ([textField isFirstResponder]) {
[textField resignFirstResponder];
}
return YES;

}

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

}

@end

效果图
1、从第一个视图传参（The only）到下一个视图（正向传参）





1、从视图传参（The only one of）到上一个视图（逆向传参）