Block作为方法参数传值的应用

 1 #import "FristViewController.h"
 2 #import "AppDateSource.h"
 3 @interface FristViewController ()
 4 @property(nonatomic,strong)UILabel *showTextLabel;
 5 @end
 6 
 7 @implementation FristViewController
 8 
 9 - (void)viewDidLoad {
10     [super viewDidLoad];
11     // Do any additional setup after loading the view.
12     UILabel *showTextLabel = [[UILabel alloc] initWithFrame:CGRectMake(100, 200, 150, 50)];
13     showTextLabel.text = @"帅哥美女";
14     showTextLabel.backgroundColor = [UIColor yellowColor];
15     showTextLabel.textAlignment = NSTextAlignmentCenter;
16     [self.view addSubview:showTextLabel];
17     UIButton *sendMesssageBtn = [UIButton buttonWithType:UIButtonTypeCustom];
18     sendMesssageBtn.backgroundColor = [UIColor yellowColor];
19     [sendMesssageBtn setTitle:@"发送" forState:UIControlStateNormal];
20     sendMesssageBtn.frame = CGRectMake(100, 300, 150, 50);
21     [sendMesssageBtn setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
22     [sendMesssageBtn addTarget:self action:@selector(sendMesssageAction) forControlEvents:UIControlEventTouchUpInside];
23     [self.view addSubview:sendMesssageBtn];
24     self.showTextLabel = showTextLabel;
25     
26 }
27 -(void)sendMesssageAction
28 {
29 #warning 第四步:block回调,即实现block
30     AppDateSource *dataBlock = [[AppDateSource alloc] init];
31     //调用方法,实现Block作为方法参数
32     [dataBlock sendMessage:@10086 andBlock:^(NSString *stirng) {
33         self.showTextLabel.text = stirng;
34     }];
35     
36     //总结:Block作为方法参数传值应用场景:一般是在处理数据的Model层进行使用;具体步骤:
37     //1.对Block进行typedef
38     //2.声明方法是Block作为方法参数
39     //3.实现声明的方法,将要传递的内容传递出去
40     //4.实现Block的回调
41 }

1 #import <Foundation/Foundation.h>
2 #warning 第一步:Block的重定义typedef
3  typedef void(^AppDateSourceBlock)(NSString *stirng);
4 @interface AppDateSource : NSObject
5 #warning 第二步:声明方法,让Block作为方法参数
6 -(void)sendMessage:(NSNumber *)number andBlock:(AppDateSourceBlock)block;
7 @end

 1 #import "AppDateSource.h"
 2 
 3 @implementation AppDateSource
 4 #warning 第三步:实现Block作为方法参数的那个方法
 5 -(void)sendMessage:(NSNumber *)number andBlock:(AppDateSourceBlock)block
 6 {
 7     NSString *string = [NSString stringWithFormat:@"%ld",[number integerValue]];
 8     block(string);
 9     
10 }
11 @end