How to make QLineEdit emit the previous and the current text in a textChanged signal
<p>I want to subclass <code>QLineEdit</code> to emit a new signal which will have the text from the moment it got focus and the new text.</p>

<p>like:</p>

<pre><code>Signals:
  void customTextChanged(const QString&amp; previousText , const QString&amp; currentText);
</code></pre>

<p>The purpose of this <code>QLineEdit</code> is to edit the name of an item, in case it exists it disables the <code>Ok_button</code> ( this is done in the <code>on_text_changed(QString)</code> slot).</p>

<p>I want to check if the user changed his mind and did set the previous name or he undoed.</p>