title: UIKeyboardWillShowNotification, UIKeyboardWillHideNotification and NSNotificationCenter problem between iOS versions
body: <p>I have several UITextFields on my view (each inside a UITableViewCell). When the keyboard is fired from any of the textfields, I need to make some animations, mainly to change the frame of the UITableView. The same must happen when the keyboard will hide.</p>
  
  <p>I have done the animation, so this is not the issue here.</p>
  
  <p>Now, I use NSNotificationCenter to catch displaying/hiding of the keyboard:</p>
  
  <pre><code>[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow) name:UIKeyboardWillShowNotification object:nil];
  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide) name:UIKeyboardWillHideNotification object:nil];
  </code></pre>
  
  <p>The problem is when the keyboard is visible (a textfield is used) and I press inside another textfield. Usually for this thing keyboard will not hide, but will stay visible.</p>
  
  <p>It works fine in iOS 4, but the problem comes in 3.1.3 (this is the version that I can test - possibly any version below 3.2). In versions older than 3.2 changing focus from a textfield directly to another textfield will fire the UIKeyboardWillHideNotification and UIKeyboardWillShowNotification.</p>
  
  <p>Anyone knows a way to perform some animation when the keyboard will really show/hide, without the NSNotificationCenter?  </p>
  
  <p>Or how can I overcome this issue with versions lower than 3.2?</p>
  
  <p>Thanks.</p>