Ios 解析后的XMLParser在字典中给出空值

我正在尝试将XML解析为json格式。我使用XMLReader第三方库（从Github下载）。解析xml后，我得到了空结果。 我试图打印NSError值，该值给出的错误为“NSErrorDomain code=4，文档为空”。我能做什么？有人能帮忙吗

• 这是我的ViewDidLoad（）代码：

    NSDictionary *xmlDict =  [[NSDictionary alloc]init];
  
     NSError *parseError = nil;
  
      xmlDict = [XMLReader dictionaryForXMLString:@"abc.xml"];  // which call's the XMLReader Class Method
  
     NSLog(@"MAIN CLASS OF Dictionary: %@",xmlDict);  // Gives the NULL Results.
  

• 这是我的XMLReader.h代码

   #import <Foundation/Foundation.h>
  
    @interface XMLReader : NSObject <NSXMLParserDelegate>
        {
          NSMutableArray *dictionaryStack;
          NSMutableString *textInProgress;
           NSError *errorPointer;
          }
  
         + (NSDictionary *)dictionaryForXMLData:(NSData *)data error:(NSError **)errorPointer;
         + (NSDictionary *)dictionaryForXMLString:(NSString *)string error:(NSError **)errorPointer;
  
            @end
  

       #import "XMLReader.h"
  
          NSString *const kXMLReaderTextNodeKey = @"text";
  
             @interface XMLReader (Internal)
  
           - (id)initWithError:(NSError **)error;
            - (NSDictionary *)objectWithData:(NSData *)data;
  
              @end
  
             @implementation XMLReader
  
               #pragma mark -
               #pragma mark Public methods
  
              + (NSDictionary *)dictionaryForXMLData:(NSData *)data error:(NSError **)error
                {
                XMLReader *reader = [[XMLReader alloc] initWithError:error];
                 NSDictionary *rootDictionary = [reader objectWithData:data];
  
               return rootDictionary;
                  }
  
             + (NSDictionary *)dictionaryForXMLString:(NSString *)string error:(NSError **)error
                {
                 NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
                  return [XMLReader dictionaryForXMLData:data error:error];
                     }
  
             #pragma mark Parsing
  
                - (NSDictionary *)objectWithData:(NSData *)data
                      {
                      // Clear out any old data
  
                         dictionaryStack = [[NSMutableArray alloc] init];
                        textInProgress = [[NSMutableString alloc] init];
  
                          // Initialize the stack with a fresh dictionary
                           [dictionaryStack addObject:[NSMutableDictionary dictionary]];
  
                        // Parse the XML
                         NSXMLParser *parser = [[NSXMLParser alloc] initWithData:data];
                          parser.delegate = self;
                           BOOL success = [parser parse];
  
                   // Return the stack's root dictionary on success
                if (success)
                 {
                    NSDictionary *resultDict = [dictionaryStack objectAtIndex:0];
                    return resultDict;
                    }
  
                return nil;
              }
  
         #pragma mark NSXMLParserDelegate methods
  
          - (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
            {
           // Get the dictionary for the current level in the stack
              NSMutableDictionary *parentDict = [dictionaryStack lastObject];
  
             // Create the child dictionary for the new element, and initilaize it with the attributes
               NSMutableDictionary *childDict = [NSMutableDictionary dictionary];
                [childDict addEntriesFromDictionary:attributeDict];
  
                  // If there's already an item for this key, it means we need to create an array
                   id existingValue = [parentDict objectForKey:elementName];
                if (existingValue)
                {
                    NSMutableArray *array = nil;
                   if ([existingValue isKindOfClass:[NSMutableArray class]])
                     {
                         // The array exists, so use it
                            array = (NSMutableArray *) existingValue;
                      }
                        else
                           {
                    // Create an array if it doesn't exist
                     array = [NSMutableArray array];
                     [array addObject:existingValue];
  
                    // Replace the child dictionary with an array of children dictionaries
                        [parentDict setObject:array forKey:elementName];
                      }
  
                    // Add the new child dictionary to the array
                     [array addObject:childDict];
                   }
                else
                  {
                  // No existing value, so update the dictionary
                      [parentDict setObject:childDict forKey:elementName];
                      }
  
                 // Update the stack
                    [dictionaryStack addObject:childDict];
                     }
  
                 - (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName
                   {
                   // Update the parent dict with text info
                       NSMutableDictionary *dictInProgress = [dictionaryStack lastObject];
  
              // Set the text property
                 if ([textInProgress length] > 0)
                     {
                          [dictInProgress setObject:textInProgress forKey:kXMLReaderTextNodeKey];
  
            // Reset the text
  
               textInProgress = [[NSMutableString alloc] init];
             }
  
                   // Pop the current dict
                      [dictionaryStack removeLastObject];
              }
  
             - (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
               {
                  // Build the text value
                       [textInProgress appendString:string];
                 }
  
                         - (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError
                  {
                         // Set the error pointer to the parser's error object
                       errorPointer = parseError;
                        NSLog(@"ERROR PONIT IS:  %@",errorPointer);
                     }
  
            @end
  

---

因此，在这段代码中，我使用它将xml数据解析为字典格式。有人能帮我解决这个问题吗？

试试这样的办法。AppDelegate.h文件中的贴花方法

+(void)downloadDataFromURL:(NSURL *)url withCompletionHandler:(void(^)(NSData *data))completionHandler;

在AppDelegate.m文件中添加方法定义

+(void)downloadDataFromURL:(NSURL *)url withCompletionHandler:(void (^)(NSData *))completionHandler{
// Instantiate a session configuration object.
      NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];

// Instantiate a session object.
      NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration];

// Create a data task object to perform the data downloading.
      NSURLSessionDataTask *task = [session dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {

    if (error != nil) {
        // If any error occurs then just display its description on the console.
        NSLog(@"%@", [error localizedDescription]);
    }
    else{
        // If no error occurs, check the HTTP status code.
        NSInteger HTTPStatusCode = [(NSHTTPURLResponse *)response statusCode];

        // If it's other than 200, then show it on the console.
        if (HTTPStatusCode != 200) {
            NSLog(@"HTTP status code = %d", HTTPStatusCode);
        }

        // Call the completion handler with the returned data on the main thread.
        [[NSOperationQueue mainQueue] addOperationWithBlock:^{
            completionHandler(data);
        }];
    }
}];
}

现在从viewController调用此方法，如viewDidload中所示

[AppDelegate downloadDataFromURL:url withCompletionHandler:^(NSData *data) {
    // Make sure that there is data.
    if (data != nil) {
        xmlDict = [XMLReader dictionaryForXMLData:data error:&parseError];
    }
}];

---

希望这能帮助您

您遇到了错误，因为您需要传递的是XML字符串而不是url。感谢您的重播。你能解释一下如何在代码中使用XML url吗？你试过我的答案了吗？