ios – 后台线程上的NSURLConnection委托方法

概述EDIT2 – 重写了这个问题 我想在后台进行一些Web服务通信.我使用Sudzc作为HTTPRequests的处理程序,它的工作原理如下： SudzcWS *service = [[SudzcWS alloc] init];[service sendOrders:self withXML:@"my xml here" action:@selector(handleOrderSending:)] EDIT2 – 重写了这个问题

我想在后台进行一些Web服务通信.我使用Sudzc作为httpRequests的处理程序,它的工作原理如下：

SudzcWS *service = [[SudzcWS alloc] init];[service sendOrders:self withXML:@"my xml here" action:@selector(handleOrderSending:)];[service release];

它将一些XML发送到Web服务,并在指定的选择器中处理响应(在这一个中,一个布尔值)：

- (voID)handleOrderSending:(ID)value{ //some controls      if ([value boolValue] == YES)    {        //my stuff    }}

当我尝试在我的sendOrders：withXML：action：方法上使用Grand Central dispatch时,我注意到没有调用选择器.我相信原因是NSURLConnection委托消息被发送到创建连接的线程但是线程没有那么久,它在方法完成时结束,杀死任何给委托的消息.

问候

EDIT1
[请求发送]方法：

- (voID) send {//dispatch_async(backgroundQueue,^(voID){    // If we don't have a handler,create a default one    if(handler == nil) {        handler = [[SoapHandler alloc] init];    }    // Make sure the network is available    if([SoapReachability connectedToNetwork] == NO) {        NSError* error = [NSError errorWithDomain:@"SudzC" code:400 userInfo:[NSDictionary dictionaryWithObject:@"The network is not available" forKey:NSLocalizedDescriptionKey]];        [self handleError: error];    }    // Make sure we can reach the host    if([SoapReachability hostAvailable:url.host] == NO) {        NSError* error = [NSError errorWithDomain:@"SudzC" code:410 userInfo:[NSDictionary dictionaryWithObject:@"The host is not available" forKey:NSLocalizedDescriptionKey]];        [self handleError: error];    }    // Output the URL if logging is enabled    if(logging) {        NSLog(@"Loading: %@",url.absoluteString);    }    // Create the request    NSMutableURLRequest* request = [NSMutableURLRequest requestWithURL: url];    if(soapAction != nil) {        [request addValue: soapAction forhttpheaderFIEld: @"SOAPAction"];    }    if(postData != nil) {        [request sethttpMethod: @"POST"];        [request addValue: @"text/xml; charset=utf-8" forhttpheaderFIEld: @"Content-Type"];        [request sethttpBody: [postData dataUsingEnCoding: NSUTF8StringEnCoding]];        if(self.logging) {            NSLog(@"%@",postData);        }    }    //dispatch_async(dispatch_get_main_queue(),^(voID){        // Create the connection        conn = [[NSURLConnection alloc] initWithRequest: request delegate: self];        if(conn) {                                        NSLog(@" POST DATA %@",receivedData);            receivedData = [[NSMutableData data] retain];                        NSLog(@" POST DATA %@",receivedData);        } else {            // We will want to call the onerror method selector here...            if(self.handler != nil) {                NSError* error = [NSError errorWithDomain:@"SoapRequest" code:404 userInfo: [NSDictionary dictionaryWithObjectsAndKeys: @"Could not create connection",NSLocalizedDescriptionKey,nil]];                [self handleError: error];            }        }    //});    //finished = NO;    //    while(!finished) {    //            //        [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];    //            //    }//});}

注释掉的部分是我尝试过的各种东西.最后一部分有效,但我不确定这是不是一个好方法.在类的NURLConnection委托方法中,会发生以下情况：

- (voID)connectionDIDFinishLoading:(NSURLConnection *)connection {NSError* error;if(self.logging == YES) {    Nsstring* response = [[Nsstring alloc] initWithData: self.receivedData     enCoding: NSUTF8StringEnCoding];    NSLog(@"%@",response);    [response release];}CXMLdocument* doc = [[CXMLdocument alloc] initWithData: self.receivedData options: 0 error: &error];if(doc == nil) {    [self handleError:error];    return;}ID output = nil;SoapFault* fault = [SoapFault faultWithXMLdocument: doc];if([fault hasFault]) {    if(self.action == nil) {        [self handleFault: fault];    } else {        if(self.handler != nil && [self.handler respondsToSelector: self.action]) {                [self.handler performSelector: self.action withObject: fault];        } else {            NSLog(@"SOAP Fault: %@",fault);        }    }} else {    CXMLNode* element = [[Soap getNode: [doc rootElement] withname: @"Body"] childAtIndex:0];    if(deserializeto == nil) {        output = [Soap deserialize:element];    } else {        if([deserializeto respondsToSelector: @selector(initWithNode:)]) {            element = [element childAtIndex:0];            output = [deserializeto initWithNode: element];        } else {            Nsstring* value = [[[element childAtIndex:0] childAtIndex:0] stringValue];            output = [Soap convert: value toType: deserializeto];        }    }    if(self.action == nil) { self.action = @selector(onload:); }    if(self.handler != nil && [self.handler respondsToSelector: self.action]) {            [self.handler performSelector: self.action withObject: output];    } else if(self.defaultHandler != nil && [self.defaultHandler respondsToSelector:@selector(onload:)]) {        [self.defaultHandler onload:output];    }}[self.handler release];[doc release];[conn release];conn = nil;[self.receivedData release];}

委托无法发送消息,因为当 – (voID)发送完成时它将死亡.

解决方法 sendOrders的方法定义表明它已经设计为以异步方式执行请求.你应该看看sendOrders的实现：withXML：action：找出是否是这种情况.

如果没有使用GCD或SudzcWS的代码看到您的实现,很难说出现了什么问题.尽管有上述警告,但以下内容可能会有所帮助.

看起来您可能在完成之前发布了SudzcWS *服务.

下列：

SudzcWS *service = [[SudzcWS alloc] init];dispatch_async(aQueue,^{    [sevice sendOrders:self withXML:xml action:@selector(handleOrderSending:)];}[service release];

除非SudzcWS保留自己,否则可能会失败.您异步调度块,它将被放入队列,并继续执行该方法.服务被释放并在块执行之前或在服务等待来自Web服务器的响应时被释放.

除非另行指定,否则调用选择器将在调用它的同一线程上执行该选择器.做类似的事情：

SudzcWS *service = [[SudzcWS alloc] init];dispatch_async(aQueue,^{    [sevice sendOrders:self withXML:xml action:@selector(handleOrderSending:)];}- (voID)handleOrderSending:(ID)value{     //some controls      //your stuff    [service release];}

应该确保sendOrders：方法和handleOrderSending：都在队列aQueue上执行,并且该服务在执行选择器之前不会被释放.

这将要求您保留指向服务的指针,以便handleOrderSending：可以释放它.您可能还想考虑简单地挂在单个SudzcWS实例上,而不是每次想要使用它时创建和释放一个,这应该使您的内存管理更容易,并有助于保持您的对象图紧.

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