title: unrecognized selector sent With NSNotifications
body: <p>I'm using NSNotifications in a ViewController to update a UILabel in another ViewController by pressing a button :</p>
  
  <pre><code>- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
  ...
  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(updateLabel:)
           name:@"LABELUPDATENOTIFICATION" object:nil];
          [[NSNotificationCenter defaultCenter] postNotificationName:@"LABELUPDATENOTIFICATION" object:@"test"]; 
  ...
  </code></pre>
  
  <p>And the code that receipt the String (@"test") :</p>
  
  <pre><code>- (void)updateLabel:(NSNotification*)notification
  {
      NSString *updatedText = (NSString*)[notification object];
      [details setText:updatedText];
  }
  </code></pre>
  
  <p>It gives me an arror when I press the button (when the first code is executed) and the second 
  code is highlited with an error: "unrecognized selector sent to instance"</p>
  
  <p>Thanks to help me, I don't really understand  notifications...</p>
  
  <p>A second question could be how send a second notification to update a second UILabel in the same Controller...</p>
  
  <p>MANY THANKS!</p>
  
  <p><strong>EDIT:
  HERE'S THE ERROR TRACE:</strong></p>
  
  <pre><code>2012-01-03 16:14:43.054 emars[3749:b303] -[ThirdViewController updateLabel:]: unrecognized selector sent to instance 0x685a0a0
  2012-01-03 16:14:43.055 emars[3749:b303] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[ThirdViewController updateLabel:]: unrecognized selector sent to instance 0x685a0a0'
  *** Call stack at first throw:
  (
      0   CoreFoundation                      0x00fb45a9 __exceptionPreprocess + 185
      1   libobjc.A.dylib                     0x01108313 objc_exception_throw + 44
      2   CoreFoundation                      0x00fb60bb -[NSObject(NSObject) doesNotRecognizeSelector:] + 187
      3   CoreFoundation                      0x00f25966 ___forwarding___ + 966
      4   CoreFoundation                      0x00f25522 _CF_forwarding_prep_0 + 50
  ...
  </code></pre>
  
  <p><strong>EDIT 2 :</strong></p>
  
  <pre><code>NSDictionary *myDictionnary = [NSDictionary dictionaryWithObjectsAndKeys:@"details",@"details de l'installation",@"recapitulatif",@"recapitulatif de l'installe",nil];
          [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(updateLabel:)
           name:@"LABELUPDATENOTIFICATION" object:nil];
          [[NSNotificationCenter defaultCenter] postNotificationName:@"LABELUPDATENOTIFICATION" object:self userInfo:myDictionnary];
  </code></pre>
  
  <p>and in the other class :</p>
  
  <pre><code>- (void)updateLabel:(NSNotification*)notification
  {
      NSDictionary *dictionnary = (NSDictionary*)[notification object];
      [details setText:[dictionnary objectForKey:@"adetails"]];
      [recapitulatif setText:[dictionnary objectForKey:@"recapitulatif"]];
  }
  </code></pre>
  
  <p>I have two errors ; a cute SIGABRT and :</p>
  
  <pre><code>unrecognized selector sent to instance 0x683d630
  2012-01-03 17:37:21.783 emars[6288:b303] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[ThirdViewController updateLabel:]: unrecognized selector sent to instance 0x683d630'
  *** Call stack at first throw:
  (
      0   CoreFoundation                      0x00fb45a9 __exceptionPreprocess + 185
      1   libobjc.A.dylib                     0x01108313 objc_exception_throw + 44
      2   CoreFoundation                      0x00fb60bb -[NSObject(NSObject) doesNotRecognizeSelector:] + 187
      3   CoreFoundation                      0x00f25966 ___forwarding___ + 966
  ...
  </code></pre>
  
  <p>THANKS for your help !!!</p>