title: QTableView sorting signal?
body: <p>I use <code>QTableView</code> + <code>QStandardItemModel</code> to show some data (data stored in some other data structure), and this table view is <strong>sortable</strong>.</p>
  
  <p>Since it is sortable, when sorting this model, I also need to sort the order of stored data. I try to implement a slot for the sorting signal, but I don't know what signal is emitted when clicking the header to start the sorting action.</p>
  
  <p>I tried the clicked signal, but it's only emitted for data row, not for the headerData.
  what should I do if I want to do something else while sorting the <code>QtableView</code> + <code>QStandardItemModel</code> ?</p>