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）