Regarding xml parsing in iphone - iphone

Question

I am developing an application in which I am doing XML parsing. I found an error in the [xmlparse parse] method.
Error:
[NSCFString bytes]: unrecognized selector sent to instance 0x3df6310
2010-04-30 00:09:46.302 SPCiphone2[4234:1003] void SendDelegateMessage
(NSInvocation*): delegate (<CFNotificationCenter 0x3d09670 [0x87dca0]>)
failed to return after waiting 10 seconds. main run loop mode:
kCFRunLoopDefaultMode
Code snippet:
responseOfWebResultData = [[NSMutableString alloc]
initWithData:responseData
encoding:NSUTF8StringEncoding];
NSLog(#"result: %#", responseOfWebResultData);
// starting the XML parsing
if (responseOfWebResultData) {
#try {
xmlParser = [[NSXMLParser alloc] initWithData:responseOfWebResultData];
[xmlParser setDelegate:self];
[xmlParser setShouldResolveExternalEntities:YES];
[xmlParser parse];
[responseOfWebResultData release];
}
#catch (NSException *e) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Please"
message:[e reason]
delegate:nil
cancelButtonTitle:#"OK"
otherButtonTitles:nil];
[alert show];
[alert release];
}
}

Answer 1

You should not be passing in a NSString* into initWithData:. You should do this:
xmlParser = [[NSXMLParser alloc] initWithData:responseData];
The error says that you're sending the message bytes to an instance of NSCFString, which is a NSString*, even though you declared it as a NSMutableString*, because this is a dynamically typed language but the class types are not automatically converted if you try to cast it to something else.