回传值(代理、通知、block)

回传值问题，一直都是困扰初学者的问题，今写者 代理、通知、block 三者的回传值做了一个小小的总结，

Main.storyboard 视图：

通过代码分别创建三个代表 代理、通知、block 的按钮，点击相应的按钮，会将相应的文本传入文本框中显示出来

代码如下：

 //  GWFMyDelegateBlockNotyView.h
 //  回传值

 #import <UIKit/UIKit.h>
 @class GWFMyDelegateBlockNotyView;

 //协议
 @protocol GWFMyDelegateBlockNotyViewDelegate <NSObject>

 //定义代理方法
 -(void)GWFMyDelegateBlockNotyView:(GWFMyDelegateBlockNotyView *)view andString:(NSString *)string andImage:(UIImage *)image;

 @end

 @interface GWFMyDelegateBlockNotyView : UIView

 //定义 id 属性
 @property (nonatomic,weak) id <GWFMyDelegateBlockNotyViewDelegate> myDelegate;

 //添加 block 属性
 @property (nonatomic,copy) void (^myBlock)(NSString *,UIImage *);

 @end

 //  GWFMyDelegateBlockNotyView.m
 //  回传值

 #import "GWFMyDelegateBlockNotyView.h"
 #import "SVProgressHUD.h"
 #import "MBProgressHUD+Ex.h"

 @implementation GWFMyDelegateBlockNotyView

 - (instancetype)init
 {
     self = [super init];
     if (self) {

 #pragma ==================================== 代理传值按钮

         //1.创建 delegateBtn
         UIButton *deleBtn = [[UIButton alloc] initWithFrame:CGRectMake(, , , )];
         //设置背景颜色
         deleBtn.backgroundColor = [UIColor redColor];
         //设置title
         [deleBtn setTitle:@"代理传值" forState:UIControlStateNormal];
         //设置 title 的颜色
         [deleBtn setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];

         //添加到控制器上
         [self addSubview:deleBtn];

         //添加 deleBtn 的监听事件
         [deleBtn addTarget:self action:@selector(deleBtnClick) forControlEvents:UIControlEventTouchUpInside];

 #pragma ==================================== Block传值按钮

         //2.创建 Block 按钮
         UIButton *blockBtn = [[UIButton alloc] initWithFrame:CGRectMake(, , , )];
         //设置背景颜色
         blockBtn.backgroundColor = [UIColor greenColor];
         //设置 title
         [blockBtn setTitle:@"Block传值" forState:UIControlStateNormal];
         //设置 title 的颜色
         [blockBtn setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];

         //添加到控制器上
         [self addSubview:blockBtn];

         //添加 blockBtn 的监听事件
         [blockBtn addTarget:self action:@selector(blockBtnClick) forControlEvents:UIControlEventTouchUpInside];

 #pragma ==================================== 通知传值按钮

         //3.创建 notyBtn
         UIButton *notyBtn = [[UIButton alloc] initWithFrame:CGRectMake(, , , )];
         //设置背景颜色
         notyBtn.backgroundColor = [UIColor blueColor];
         //设置 title
         [notyBtn setTitle:@"通知传值" forState:UIControlStateNormal];
         //设置 notyBtn 的 title 的颜色
         [notyBtn setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];

         //添加到控制器上
         [self addSubview:notyBtn];

         //添加 notyBtn 的监听事件
         [notyBtn addTarget:self action:@selector(notyBtnClick) forControlEvents:UIControlEventTouchUpInside];

     }
     return self;
 }

 //实现按钮的点击事件
 #pragma mark -------代理

 -(void)deleBtnClick {
     NSString *myText = @"这是代理传来的值";
     UIImage *image = [UIImage imageNamed:@"0 (3)"];

     //判断代理
     if ([self.myDelegate respondsToSelector:@selector(GWFMyDelegateBlockNotyView:andString:andImage:)]) {

         //执行代理
         [self.myDelegate GWFMyDelegateBlockNotyView:self andString:myText andImage:image];

         dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)( * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

             [SVProgressHUD showWithStatus:@"正在连接..." maskType:SVProgressHUDMaskTypeBlack];
         });

         dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)( * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

             [SVProgressHUD dismiss];
             UIApplication *app = [UIApplication sharedApplication];
             NSURL *url = [NSURL URLWithString:@"http://www.dianping.com"];
             [app openURL:url];

         });
     }
 }

 #pragma mark -------block

 -(void)blockBtnClick {
     NSString *myText = @"这是Block传来的值";
     UIImage *image = [UIImage imageNamed:@"0 (2)"];
     self.myBlock(myText,image);

     dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)( * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

         [SVProgressHUD showWithStatus:@"正在连接..." maskType:SVProgressHUDMaskTypeBlack];
     });

     dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)( * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

         [SVProgressHUD dismiss];

         UIApplication *app = [UIApplication sharedApplication];
         NSURL *url = [NSURL URLWithString:@"http://www.10010.com"];
         [app openURL:url];

     });
 }

 #pragma mark --------通知

 -(void)notyBtnClick {
     NSString *myText = @"这是通知传来的值";
     UIImage *image = [UIImage imageNamed:@"0 (7)"];

     //发布一个通知
     [[NSNotificationCenter defaultCenter] postNotificationName:@"myNoty" object:nil userInfo:@{@"myText":myText,@"image":image}];

     dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)( * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

         [SVProgressHUD showWithStatus:@"正在连接..." maskType:SVProgressHUDMaskTypeBlack];
     });

     dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)( * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

         [SVProgressHUD dismiss];

     UIApplication *app = [UIApplication sharedApplication];
     NSURL *url = [NSURL URLWithString:@"http://www.youku.com"];
     [app openURL:url];

     });
 }

 @end

控制器中：

 //  ViewController.m
 //  回传值

 #import "ViewController.h"
 #import "GWFMyDelegateBlockNotyView.h"

 @interface ViewController ()<GWFMyDelegateBlockNotyViewDelegate>

 @property (weak, nonatomic) IBOutlet UILabel *myLabel;
 @property (weak, nonatomic) IBOutlet UIImageView *myImageView;

 @end

 @implementation ViewController

 - (void)viewDidLoad {
     [super viewDidLoad];

     self.view.backgroundColor = [UIColor orangeColor];
     //添加 myView
     GWFMyDelegateBlockNotyView *myView = [[GWFMyDelegateBlockNotyView alloc] init];
     myView.frame = CGRectMake(, , , );
     [self.view addSubview:myView];

     //设置代理
     myView.myDelegate = self;

     //block
     myView.myBlock = ^(NSString *block,UIImage *myBlock){
         self.myLabel.text = block;
         self.myImageView.image = myBlock;
     };

     //添加通知的一个监听事件
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(noty:) name:@"myNoty" object:nil];

 }

 //实现代理方法
 -(void)GWFMyDelegateBlockNotyView:(GWFMyDelegateBlockNotyView *)view andString:(NSString *)string andImage:(UIImage *)image {
     self.myLabel.text = string;
     self.myImageView.image = image;
 }

 //实现通知的监听方法
 -(void)noty:(NSNotification *)noty {
     self.myLabel.text = noty.userInfo[@"myText"];
     self.myImageView.image = noty.userInfo[@"image"];
 }

 @end

执行结果：

1> 点击代理按钮后：

2> 点击通知按钮后:

3>点击block按钮后: