ios - 使用sendAsynchronousRequest :queue:completionHandler: for URL request

Question

我正在更新另一位开发者创建的 iOS 应用程序。他使用 ASIHTTPRequest 来处理 http 请求。但是，我必须使用的应用程序版本崩溃了。由于 ASIHTTPRequest 不再更新，我当时想我应该改用 AFNetworking，但它太复杂了我无法弄清楚。

所以最后我想我可以单独使用 NSURLConnection。

这是我要替换的原始代码:

-(NSArray*)readUTF16LEFeed:(NSURL*) urlToRead{
    ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:urlToRead];
    [request startSynchronous];
    NSError *error = [request error];
    if (!error) {
        lastModified = [NSDate date];
        NSData *response = [request responseData];//UTF-16LE
        NSString* responseString = [[NSString alloc] initWithData:response encoding:NSUTF16LittleEndianStringEncoding];
        DLog(@"string is: %@",responseString);
        responseString = [responseString stringByReplacingOccurrencesOfString:@"ISO-8859-1" withString:@"UTF16-LE"];
        NSData* data = [responseString dataUsingEncoding:NSUTF16LittleEndianStringEncoding];
        return [self parseNamesFromXML:data];
    }
    return nil;
}

下面是我尝试使用的:

-(NSArray*)readUTF16LEFeed:(NSURL*) urlToRead{

    NSURLRequest *request = [NSURLRequest requestWithURL:urlToRead];
    [NSURLConnection sendAsynchronousRequest:request
                                       queue:[NSOperationQueue mainQueue]
                           completionHandler:^(NSURLResponse *response, NSData *data, NSError *error ) {

                               if ([data length] >0 && error == nil)
                               {
                                   // DO YOUR WORK HERE
                                   lastModified = [NSDate date];

                                   //   NSData *response = [request responseData];//UTF-16LE
                                   NSString* responseString = [[NSString alloc] initWithData:data encoding: NSUTF16LittleEndianStringEncoding];
                                   DLog(@"string is: %@",responseString);
                                   responseString = [responseString stringByReplacingOccurrencesOfString:@"ISO-8859-1" withString:@"UTF16-LE"];
                                   NSData* data = [responseString dataUsingEncoding:NSUTF16LittleEndianStringEncoding];
                                   return [self parseNamesFromXML:data];
                               }

                               else if ([data length] == 0 && error == nil)
                               {
                                   NSLog(@"Nothing was downloaded.");
                               }
                               else if (error != nil){
                                   NSLog(@"Error = %@", error);
                               }
                           }];
    return nil;
}

但是，我收到错误消息“不兼容的 block 指针类型将 NSArray 发送到类型为 void 的参数。而且“控件可能到达非 void block 的末尾。”

我怎样才能让它工作？

Answer 1

将您的方法的返回类型设置为 void。不要退回任何东西。只需调用 [self parseNamesFromXML:data];方法。

-(void)readUTF16LEFeed:(NSURL*) urlToRead{


NSURLRequest *request = [NSURLRequest requestWithURL:urlToRead];
[NSURLConnection sendAsynchronousRequest:request
                                   queue:[NSOperationQueue mainQueue]
                       completionHandler:^(NSURLResponse *response, NSData *data, NSError *error ) {

                       if ([data length] >0 && error == nil)
                       {

                           // DO YOUR WORK HERE
                           lastModified = [NSDate date];

                      //   NSData *response = [request responseData];//UTF-16LE
                           NSString* responseString = [[NSString alloc] initWithData:data encoding: NSUTF16LittleEndianStringEncoding];
                           DLog(@"string is: %@",responseString);
                           responseString = [responseString stringByReplacingOccurrencesOfString:@"ISO-8859-1" withString:@"UTF16-LE"];
                           NSData* data = [responseString dataUsingEncoding:NSUTF16LittleEndianStringEncoding];
                           [self parseNamesFromXML:data];
                       }


                       else if ([data length] == 0 && error == nil)
                       {
                           NSLog(@"Nothing was downloaded.");
                       }
                       else if (error != nil){
                           NSLog(@"Error = %@", error);
                       }

                   }];
}

在 parseNamesFromXML 方法中，处理您的结果并将结果数组分配给一个属性。您可以随时随地访问它。

-(void) parseNamesFromXML:(NSData *)xmlData
{     
    NSError *error;          
    //DLog(@"data is %@", [[NSString alloc] initWithData:xmlData encoding:NSUTF8StringEncoding ]);     

    GDataXMLDocument *doc = [[GDataXMLDocument alloc] initWithData:xmlData                                                            options:0 error:&error];          

    if (doc)
    {         
        self.dataArray = [self parseXmlDoc:doc]; 
    }              
}