title: change the color of a single QListView index upon double clicking it
body: <p>First off, I'm a Qt newbie:<br>
  I would like to change a QListView entry's text color upon double clicking it but I'm not exactly sure how to go about it. I'm able to get the index of the item double clicked:</p>
  
  <pre><code>void Widget::on_HostList_doubleClicked(const QModelIndex &amp;index)
  {
      QMessageBox msgBox;
      msgBox.setText(QString::number(index.row()));
      msgBox.exec();
  }
  </code></pre>
  
  <p>How can I do this?</p>