Question

使用这个XML-to-NSDictionary类时，我遇到了一个奇怪的问题。真的很棒。突然间，我们发现了一个使用此问题的问题。让我解释一下......当我只有一个项目时，应用程序崩溃了。但是当我有多个项目时，应用程序没有崩溃。

当我只有一个要解析的项目时，解析后如果我打印计数它显示为6

但是当我有多个项目时，解析后打印计数时它会正确显示

**

崩溃日志： - - [NSCFString objectAtIndex：]：发送到实例的无法识别的选择器 0x5c9a040由于终止应用程序未捕获的异常 'NSInvalidArgumentException'，原因： ' - [NSCFString objectAtIndex：]：无法识别的选择器发送到实例 0x5c9a040'

**

请帮帮我，谢谢你的时间

源代码

-(void)RequestUpdate
    {
      NSDictionary *mailDict = [[XMLReader dictionaryForXMLString:responseXML error:nil] 

      valueForKeyPath:@"response.mails.mail"];

      NSLog(@"MAILS>MAIL COUNT %d %@", [mailDict count], mailDict);
    }

#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];
    [reader release];
    return rootDictionary;
}

+ (NSDictionary *)dictionaryForXMLString:(NSString *)string error:(NSError **)error
{
    NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
    return [XMLReader dictionaryForXMLData:data error:error];
}

#pragma mark -
#pragma mark Parsing

- (id)initWithError:(NSError **)error
{
    if ((self = [super init]))
    {
        errorPointer = error;
    }
    return self;
}

- (void)dealloc
{
    [dictionaryStack release];
    [textInProgress release];
    [super dealloc];
}

- (NSDictionary *)objectWithData:(NSData *)data
{
    // Clear out any old data
    [dictionaryStack release];
    [textInProgress release];

    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] autorelease];
    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 -
#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 release];
        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;
}

@end

示例XML数据

<response>
  <mails>
    <mail id="4e12a3b04ff5ae0774000082">
      <created_on>2011-07-05T05:40:00+00:00</created_on>
      <updated_on>2011-07-05T05:40:00+00:00</updated_on>
      <creator id="4e0abdff54b53058ff0000a2"><name>Merk Warn</name></creator>
      <text>eee</text>
    </mail>
    <mail id="4e12dcvxva3b04ff5ae0774000082">
      <created_on>2011-07-05T05:40:00+00:00</created_on>
      <updated_on>2011-07-05T05:40:00+00:00</updated_on>
      <creator id="4e0abdff54b53058ff0000a2"><name>Merk Warn</name></creator>
      <text>eee</text>
    </mail>
 </mails>
</response>

Answer 1

这是因为如果只有一个元素，标签将直接存储为NSDictionary对象。您获得的计数是字典中键值对的数量。

你可以用不同的方式处理，

-(void)update
{
    id value = [[XMLReader dictionaryForXMLString:responseXML error:nil] valueForKeyPath:@"response.mails.mail"];

    NSArray * mails;
    if ( [value isKindOfClass:[NSDictionary class]] ) {
        mails = [NSArray arrayWithObject:value];
    }
    else {
        mails = (NSArray *)value;
    }

    /* `mails` is an array of <mail> based dictionaries */
}

你必须妥善保留它。

解析时帮我解决奇怪的问题

源代码

1 个答案: