一、添加SystemConfiguration和MobileCoreServices 框架

二、下载AFNetworking资源包 https://github.com/AFNetworking/AFNetworking

三、在工程的Supporting File群组中打开预编译头文件XXX-Prefix.pch，然后在别的import后面添加如下一行代码#import “AFNetworking”

四、AFNetworking通过网络来加载和处理结构化的数据非常明智，它支持JSON,XML,Property List

1. static NSString*const BaseURLString = @"http://www.raywenderlich.com/downloads/weather_sample/";  
2.      
3.     // 1  
4.     NSString *weatherUrl = [NSStringstringWithFormat:@"%@weather.php?format=json",BaseURLString];  
5.     NSURL *url = [NSURLURLWithString:weatherUrl];  
6.     NSURLRequest *request = [NSURLRequestrequestWithURL:url];  
7.      
8.     // 2  
9.     AFJSONRequestOperation *operation =  
10.     [AFJSONRequestOperationJSONRequestOperationWithRequest:request  
11.                                               success:^(NSURLRequest*request, NSHTTPURLResponse *response, id JSON) {  
12.                                                  //  
13.                                                  NSDictionary*dicWeather = (NSDictionary *)JSON;  
14.                                                  NSLog(@"result:%@",dicWeather);  
15.                                               }  
16.                                               failure:^(NSURLRequest*request, NSHTTPURLResponse *response, NSError *error, id JSON) {  
17.                                                  UIAlertView*alertView = [[UIAlertView alloc] initWithTitle:@"Error RetrievingWeather"  
18.                                                                                                message:[NSStringstringWithFormat:@"%@",error]  
19.                                                                                               delegate:self  
20.                                                                                       cancelButtonTitle:@"OK"  
21.                                                                                       otherButtonTitles: nil];  
22.                                                  [alertView show];  
23.                                               }];  
24.     // 5  
25.     [operation start];  

五、AFNetWorking异步加载图片（不堵塞主线程）

1. #import “UIImageView+AFNetworking.h”  
2. UIImageView *imageView = [[UIImageView alloc]initWithFrame:CGRectMake(40, 80, 40, 40)];  
3.     __weak UIImageView *_imageView = imageView;  
4.     [imageViewsetImageWithURLRequest:[[NSURLRequest alloc] initWithURL:[NSURLURLWithString:@"http://www.worldweatheronline.com/images/wsymbols01_png_64/wsymbol_0001_sunny.png"]]  
5.                    placeholderImage:[UIImage imageNamed:@"placeholder.png"]  
6.                            success:^(NSURLRequest *request,NSHTTPURLResponse *response, UIImage *image) {  
7.                               _imageView.image = image;  
8.                                
9.                               [_imageView setNeedsDisplay];  
10.                            }  
11.                            failure:^(NSURLRequest *request, NSHTTPURLResponse*response, NSError *error) {  
12.                               ;  
13.                            }];  
14.     [self.view addSubview:imageView];  

六、GET 和POST请求

1. AFHTTPClient *client= [[AFHTTPClient alloc] initWithBaseURL:baseURL];  
2. [clientregisterHTTPOperationClass:[AFJSONRequestOperation class]];  
3. [clientsetDefaultHeader:@"Accept" value:@"application/json"];  
4. [client postPath:@"weather.php"  
5.               parameters:parameters  
6.                 success:^(AFHTTPRequestOperation *operation, id responseObject) {  
7.                      self.weather =responseObject;  
8.                      self.title = @"HTTPPOST";  
9.                      [self.tableViewreloadData];  
10.                  }  
11.                 failure:^(AFHTTPRequestOperation *operation, NSError*error) {  
12.                      UIAlertView *av =[[UIAlertView alloc] initWithTitle:@"Error Retrieving Weather"  
13.                                                                  message:[NSStringstringWithFormat:@"%@",error]  
14.                                                                 delegate:nil  
15.                                                        cancelButtonTitle:@"OK" otherButtonTitles:nil];  
16.                      [av show];  
17.    
18.                  }  
19.          ];  
20.    
21. [client getPath:@"weather.php"  
22.              parameters:parameters  
23.                success:^(AFHTTPRequestOperation *operation, id responseObject) {  
24.                     self.weather =responseObject;  
25.                     self.title = @"HTTP GET";  
26.                     [self.tableViewreloadData];  
27.                 }  
28.                failure:^(AFHTTPRequestOperation *operation, NSError*error) {  
29.                     UIAlertView *av =[[UIAlertView alloc] initWithTitle:@"Error Retrieving Weather"  
30.                                                                  message:[NSStringstringWithFormat:@"%@",error]  
31.                                                                delegate:nil  
32.                                                       cancelButtonTitle:@"OK" otherButtonTitles:nil];  
33.                     [av show];  
34.    
35.                 }  
36.          ];  

注：

1、AFJSONOperation,AFPropertyListOperation, AFXMLOperation用来解析结构化数据。

2、UIImageView+AFNetworking用来快捷的填充image view

3、AFHTTPClient用来进行更底层的请求

4、用自定义的AFHTTPClient子类来访问一个web service。

5、AFNetworkActivityIndicatiorManager用来给用户做出网络访问的提示。

6、AFImageRequestOperation用来加载图片