cfstring length message sent to deallocated instance? - iphone

Question

I m doing the concept of autocomplete feature for a textField and in doing so I m getting the following error:
"cfstring length message sent to deallocated instance"
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
if( textField == txtcity)
{
autocompleteTableView.hidden = NO;
NSString *substring = [NSString stringWithString:textField.text];
substring = [substring stringByReplacingCharactersInRange:range withString:string];
[self searchAutocompleteEntriesWithSubstring:substring];
return YES;
}
}
- (void)searchAutocompleteEntriesWithSubstring:(NSString *)substring {
subString2=[NSString stringWithFormat:#"%#",substring];
NSMutableData *data = [[NSMutableData alloc] init];
self.receivedData = data;
[data release];
NSURL *jsonUrl =[NSURL URLWithString:[NSString stringWithFormat:#"http://210.90.32.122/services/AutoService.svc/GetCities/?p=%#&k=%#",substring,txtId.text]];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:jsonUrl];
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request
delegate:self];
self.connection = connection;
[connection start];
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
[receivedData setLength:0];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[receivedData appendData:data];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
parser = [[NSXMLParser alloc] initWithData:receivedData];
[parser setDelegate:self];
[parser setShouldProcessNamespaces:NO];
[parser setShouldReportNamespacePrefixes:NO];
[parser setShouldResolveExternalEntities:NO];
[parser parse];
[parser release];
NSLog(#"%#",arr2);
if([arr2 count]!=0)
{
self.autocompleteUrls = [[NSMutableArray alloc] init];
if(autocompleteTableView)
[autocompleteTableView removeFromSuperview];
autocompleteTableView = [[UITableView alloc] initWithFrame:CGRectMake(88, 428, 200,[arr2 count]*20) style:UITableViewStyleGrouped];
autocompleteTableView.delegate = self;
autocompleteTableView.dataSource = self;
autocompleteTableView.scrollEnabled = YES;
autocompleteTableView.rowHeight=20;
[self.view addSubview:autocompleteTableView];
for(int i=0;i<[arr2 count];i++)
{
NSString *curString = [[arr2 objectAtIndex:i] valueForKey:#"Name"];
NSRange substringRange = [curString rangeOfString:subString2]; //error at this line
if (substringRange.location == 0)
[autocompleteUrls addObject:curString];
}
}
[autocompleteTableView reloadData];
txtcity.text=subString2;
[txtcity resignFirstResponder];
}
my subString2 is becoming null.But I have retained it while decalring
#property(nonatomic,retain)NSString *subString2;
Where Im going wrong.Couldn't understand where it is being deallocated..

Answer 1

You're not actually retain it. You're setting the object variable subString2 not though the property, that is the reason. Try this:
self.subString2 = [NSString stringWithFormat:#"%#",substring];
But it is not very good practise to get to the object variables from the object through the properties. There is two options:
[subString2 release];
subString2 = [[NSString stringWithFormat:#"%#",substring] copy];
OR
[subString2 release];
subString2 = [[NSString stringWithFormat:#"%#",substring] retain];