Iphone NSXMLParser与NSOperation一起工作不正常

为了向服务器发送下载数据的请求，我使用了NSOperation。在收到数据后，我使用NSXMLParser来解析响应，但它没有调用解析器委托方法，例如

-(void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName 

或

谁能告诉我哪里做错了

//Creating NSOperation as follows:
NSOperationQueue *operationQueue = [NSOperationQueue new];
NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(createRequestToGetData) object:nil]; 
[operationQueue addOperation:operation];
[operation release];    

-(void)createRequestToGetData
{
    NSError *error;
    NSURL *theURL = [NSURL URLWithString:myUrl];
    NSData *data = [NSData dataWithContentsOfURL:theURL];

    MyXMLParser *theXMLParser = [[MyXMLParser alloc]init];
    NSError *theError = NULL;
    [theXMLParser parseXMLFileWithData:data parseError:&theError];
    NSLog(@"Parse data:%@",theXMLParser.mParsedDict); //Cursor is not coming here.
    [theXMLParser release];
}

注意：MyXMLParser是NSObject的子类，它实现了Parser委托方法，但我的游标没有到达NSLog。当将调试点放在Parser委托方法中时，发现这些方法没有被调用

谁能告诉我问题出在哪里，我如何解决这个问题

---

提前谢谢

我通过创建NSOperation的子类解决了上述问题，并在NSOperation子类的主方法中进行解析，如下所示：

//DataDownloadOperation.h
#import <Foundation/Foundation.h>

@interface DataDownloadOperation : NSOperation
{
    NSURL *targetURL;
}
@property(retain) NSURL *targetURL;
- (id)initWithURL:(NSURL*)url;

@end


//DataDownloadOperation.m
#import "DataDownloadOperation.h"
#import "MyXMLParser.h"

@implementation DataDownloadOperation
@synthesize targetURL;

- (id)initWithURL:(NSURL*)url
{
    if (![super init]) return nil;
    self.targetURL = url;
    return self;
}

- (void)dealloc {
    [targetURL release], targetURL = nil;
    [super dealloc];
}

- (void)main {

    NSData *data = [NSData dataWithContentsOfURL:self.targetURL];
    MyXMLParser *theXMLParser = [[MyXMLParser alloc]init];
    NSError *theError = NULL;
    [theXMLParser parseXMLFileWithData:data parseError:&theError];
    NSLog(@"Parse data1111:%@",theXMLParser.mParsedDict);
    [theXMLParser release];
}
@end
//Created NSOperation as follows:
NSURL *theURL = [NSURL URLWithString:myurl];
        NSOperationQueue *operationQueue = [NSOperationQueue new];
        DataDownloadOperation *operation = [[DataDownloadOperation alloc] initWithURL:theURL];
         [operationQueue addOperation:operation];
         [operation release];

//DataDownloadOperation.h
#进口
@接口数据下载操作：NSOperation
{
NSURL*目标URL；
}
@属性（保留）NSURL*targetURL；
-（id）initWithURL:（NSURL*）url；
@结束
//DataDownloadOperation.m
#导入“DataDownloadOperation.h”
#导入“MyXMLParser.h”
@数据下载操作的实现
@合成targetURL；
-（id）initWithURL:（NSURL*）url
{
如果（！[super init]）返回nil；
self.targetURL=url；
回归自我；
}
-（无效）解除锁定{
[targetURL发布]，targetURL=nil；
[super dealoc]；
}
-（无效）主要{
NSData*data=[NSData dataWithContentsOfURL:self.targetURL]；
MyXMLParser*theXMLParser=[[MyXMLParser alloc]init]；
n错误*错误=NULL；
[XmlParser解析XmlFileWithData:data parseError:&theError]；
NSLog（@“Parse data1111:%@”，即xmlparser.mparseddct）；
[XmlParser发行版]；
}
@结束
//创建了如下操作：
NSURL*theURL=[NSURL-URLWithString:myurl]；
NSOperationQueue*操作队列=[NSOperationQueue新建]；
DataDownloadOperation*操作=[[DataDownloadOperation alloc]initWithURL:theURL]；
[操作队列添加操作：操作]；
[操作释放]；

是否调用了

createRequestToGetData

？您有断点吗？请包含MyXMLParser类的代码。

parseXMLFileWithData:parseError:

是否创建一个NSXMLParser，将自身设置为委托，并调用NSXMLParser的解析方法？是否调用createRequestToGetData，MyXMLParser将自身设置为NSXMLParser委托。

//DataDownloadOperation.h
#import <Foundation/Foundation.h>

@interface DataDownloadOperation : NSOperation
{
    NSURL *targetURL;
}
@property(retain) NSURL *targetURL;
- (id)initWithURL:(NSURL*)url;

@end


//DataDownloadOperation.m
#import "DataDownloadOperation.h"
#import "MyXMLParser.h"

@implementation DataDownloadOperation
@synthesize targetURL;

- (id)initWithURL:(NSURL*)url
{
    if (![super init]) return nil;
    self.targetURL = url;
    return self;
}

- (void)dealloc {
    [targetURL release], targetURL = nil;
    [super dealloc];
}

- (void)main {

    NSData *data = [NSData dataWithContentsOfURL:self.targetURL];
    MyXMLParser *theXMLParser = [[MyXMLParser alloc]init];
    NSError *theError = NULL;
    [theXMLParser parseXMLFileWithData:data parseError:&theError];
    NSLog(@"Parse data1111:%@",theXMLParser.mParsedDict);
    [theXMLParser release];
}
@end
//Created NSOperation as follows:
NSURL *theURL = [NSURL URLWithString:myurl];
        NSOperationQueue *operationQueue = [NSOperationQueue new];
        DataDownloadOperation *operation = [[DataDownloadOperation alloc] initWithURL:theURL];
         [operationQueue addOperation:operation];
         [operation release];