“-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data” not called

问题

Have a look to this code snippet:-

-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{               
    [webData setLength: 0];           
}



-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data

{
    NSLog(@"Recieving Data...");
    [webData appendData:data];

}



-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    NSLog(@"ERROR with theConenction");
    [connection release];
    [webData release];
}

-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    NSLog(@"DONE. Received Bytes: %d", [webData length]);
    NSLog(theXML);


}   

I am calling a SOAP web service.There are no errors or warnings displayed in my code. When I hit the web service through safari it works fine. But the problem arises when I try hit it through my codes. Everything works fine but the connection:didRecieveData does not gets called. Thus, I get no data in the webData variable. This webData is a NSMutableData object. The problem seems to be silly but any one with any answers ....

Thank You All.

回答1:

I suspect you are having a memory management issue. I could be mistaken on this, but I believe that even:

NSURLConnection* connection=[[NSURLConnection alloc] initWithRequest:request delegate:self];

won't work, because connection will be released at the end of the containing method, when connection goes out of scope. Make sure NSURLConnection *connection and NSMutableData *data are declared as member variables where ever you are doing this, and that you alloc and init them appropriately. My code usually looks like:

    NSURLRequest *request = [NSURLRequest requestWithURL:url
                                          cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
                                          timeoutInterval:30.0];
    // cancel any old connection
    if(connection) {
        [connection cancel];
        [connection release];
    }
    // create new connection and begin loading data
    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
    if(connection) {
        // if the connection was created correctly, release old data (if any), and alloc new
        [data release];
        data = [[NSMutableData data] retain];
    }

Also, release the connection and data in dealloc. For good measure, release and set them to nil at the very end of didFailWithError and didFinishLoading:

[connection release];
connection = nil;
[data release];
data = nil;

Good luck; I've done this a million times, let me know if you cannot get it working.

回答2:

You don't happen to be calling the NSConnection in a thread do you? If you are then what's happening is that the thread is terminating before NSConnection and its delegates have finished so it'll just bomb out without an error.

A workaround for this is in this thread

回答3:

You're not getting any error messages in didFailWithError either? Kind of a silly suggestion, but are you sure you're setting the proper NSURLConnection delegate?

NSURLConnection* connection=[[NSURLConnection alloc] initWithRequest:request delegate:self];

Sometimes it's something small like that.

Another idea is to drop in a toolkit like ASIHTTPRequest and see if it works going through them.

回答4:

There also could be problems, if are trying to start NSURLConnection from another Thread. Please call method [connection start] on main thread, if you have not customized Run Loop for it.

来源：https://stackoverflow.com/questions/1244137/voidconnectionnsurlconnection-connection-didreceivedatansdata-data