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(0, 0, 100, 100)];
        //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(110, 0, 100, 100)];
        //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(215, 0, 100, 100)];
        //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)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
            
            [SVProgressHUD showWithStatus:@"正在连接..." maskType:SVProgressHUDMaskTypeBlack];
        });
        
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * 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)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        
        [SVProgressHUD showWithStatus:@"正在连接..." maskType:SVProgressHUDMaskTypeBlack];
    });
    
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * 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)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        
        [SVProgressHUD showWithStatus:@"正在连接..." maskType:SVProgressHUDMaskTypeBlack];
    });
    
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * 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(30, 150, 300, 200);
    [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: