title: UITextFieldDelegate, checking if textFields have text in it
body: <p>i have a little problem.
  There are two textFields in my TableView which set the property of an object. In order to do so i want to force the user to write something in the textField before the string is actually been set to the object. So basically a simple <code>([textField.text length] &gt; 0)</code> thing.
  But i want that the user have to write strings in both the two textFields to finally enable the "Done"-Button.
  I solved this earlier but with only one text Field with the following <code>UITextFieldDelegate</code> method.</p>
  
  <pre><code>- (BOOL)textField:(UITextField *)theTextField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
      {
          NSString *newText = [theTextField.text stringByReplacingCharactersInRange:range withString:string];
          self.doneBarButton.enabled = ([newText length] &gt; 0);
          return YES;
      }
  </code></pre>
  
  <p>My solution for the new problem, so now with two textFields is this one:</p>
  
  <pre><code>- (BOOL)textField:(UITextField *)theTextField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
  {
      NSString *newText = [theTextField.text stringByReplacingCharactersInRange:range withString:string];
  
      if ([theTextField.placeholder isEqualToString:@"textField1"]) {
          if ([theTextField.text length] &gt; 0) {
              enabledVokabel = YES;
          } else {
              enabledVokabel = NO;
          }
      }
      if ([theTextField.placeholder isEqualToString:@"textField2"]) {
          if ([theTextField.text length] &gt; 0) {
              enabledUebersetung = YES;
          } else {
              enabledUebersetung = NO;
          }
      }
  
      self.doneBarButton.enabled = (enabledVokabel &amp;&amp; enabledUebersetung);
      return YES;
  }
  </code></pre>
  
  <p>So i want the doneBarButton been enabled when both of the textFields (textField1 and textField2) are filled with text. But i want it that way that if the user has deleted the text he/she just wrote in the doneBarButton is disabled as soon as the textFields are empty.
  It doesn't work that way. Do you have a solution? Or maybe a better way to solve it?</p>