title: how to set new text in JTextField after creation?
body: <p>I have a jTextField , and I set it's value to a certain sum when I create the frame.<br>
  Here is the initiation code:</p>
  
  <pre><code>totalTextField.setText(
              itemsPriceTextField.getText() +           
                      Float.toString(orderDetails.delivery)
  );
  </code></pre>
  
  <p>This textfield should show a sum of items selected by the user.<br>
  The selection is done on a different frame,  and both frames are visible / invisible
  at a time.<br>
  The user can go back and forth and add / remove items.  </p>
  
  <p>Now,  every time i set this frame visible again,  I need to reload the value set to that field<br>
  (maybe no changes were made,  but if so,  I need to set the new correct sum) .  </p>
  
  <p>I'm quite desperate with it.<br>
  Can anyone please give me a clue?<br>
  Thanks in advance! :)  </p>