title: NSXMLParser parserDidStartDocument freezes app
body: <p>I tried to add some operations after call</p>
  
  <pre><code>- (void)parserDidStartDocument:(NSXMLParser *)parser {
  //NSLog(@"found file and started parsing");
  alertView = [[UIAlertView alloc] initWithTitle:@"Caricamento..."
                                         message:@"\n"
                                        delegate:self
                               cancelButtonTitle:nil
                               otherButtonTitles:nil];
  
  UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
  spinner.center = CGPointMake(139.5, 75.5); // .5 so it doesn't blur
  [alertView addSubview:spinner];
  [spinner startAnimating];
  [alertView show];
  </code></pre>
  
  <p>}</p>
  
  <p>But it freeze the app for a while, and then, when finished the XML parse, loads the AlertView, ecc. Same thing with the UIRefreshControl. I slide down the tableView, and the app freeze while parsing, I cant see the spinner rotating.</p>
  
  <p>Any idea?</p>
  
  <p>Edit:
  here I call the first time the parser:</p>
  
  <pre><code>- (void)viewDidAppear:(BOOL)animated {
  [super viewDidAppear:animated];
  
  NSString * path = @"thexmlpath.xml";
  if(!caricato)
      [NSThread detachNewThreadSelector:@selector(parseXMLFileAtURL:) toTarget:self withObject:path];
      //[self parseXMLFileAtURL:path];
  
  caricato = YES;}
  </code></pre>
  
  <p>Here I call when I use the RefreshControl:</p>
  
  <pre><code>- (void)refreshControlRequest{
  
  
  NSLog(@"refreshing...");
  
  NSString * path = @"thexmlpath.xml";
  [self performSelector:@selector(parseXMLFileAtURL:) withObject:path];}
  </code></pre>