//联系人:石虎QQ: 1224614774昵称:嗡嘛呢叭咪哄

/**

注意点: 1.看 GIF 效果图.

2.看连线视图的效果图.

3.看实现代码(直接复制实现效果).

4.下载demo链接:(点击或者是https://gitee.com/ShiHu132/BlockChuanZhi)

*/

一、GIF 效果图:

二、连线视图的效果图:

图1:

图2:

三、实现代码:

=========================

===================================================

==========================

控制器1:ViewController.m

// ViewController.m

// Block传值~demo

//

// Created by石虎on 2017/9/22.

#import"ViewController.h"

#import"SHBlockViewController.h"

@interfaceViewController()

@property(weak,nonatomic)IBOutletUILabel*blockLabel;

- (IBAction)blockClick:(UIButton*)sender;

@end

@implementationViewController

//逆向传值

- (IBAction)blockClick:(UIButton*)sender {

SHBlockViewController*blockVC =[[SHBlockViewControlleralloc]init];

//接收方只需要调用传输方的block方法

[blockVCshowTheResultToFirst:^(NSString*secondString) {

self.blockLabel.text= secondString;

}];

[selfpresentViewController:blockVCanimated:YEScompletion:nil];

}

- (void)viewDidLoad {

[superviewDidLoad];

}

@end

================

=======

控制器2:SHBlockViewController.m

// SHBlockViewController.m

// Block传值~demo

// Created by石虎on 2017/9/22.

#import"SHBlockViewController.h"

#import"ViewController.h"

@interfaceSHBlockViewController()

@property(weak,nonatomic)IBOutletUITextField*startValueField;

- (IBAction)startValueClick:(UIButton*)sender;

@end

@implementationSHBlockViewController

//返回到上级界面

- (IBAction)startValueClick:(UIButton*)sender {

[selfdismissViewControllerAnimated:YEScompletion:nil];

}

// block实际执行的内容

-(void)showTheResultToFirst:(SHBlockViewBlock)block {

self.passValue= block;

}

//在即将消失view时，将block方法的参数设置为文本框的内容

-(void)viewWillDisappear:(BOOL)animated {

if(self.passValue!=nil) {

self.passValue(self.startValueField.text);

}

}

//退出键盘

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent*)event {

[self.viewendEditing:YES];

}