Good morning to all, this is my scenario:
I wrote an application based on QMainWindow containing a centralwidget.
The centralwidget contains 2 classes inherited from QWidget lets say ww1 and ww2.
Now I would, pressing tab, move the focus between ww1 and ww2.
I tried to override the focusInEvent - focusOutEvent methods of every QWidget
Qt Code: 
  1. class MyWidget : public QWidget
  2. {
  3.    //code
  4. protected:
  5.     virtual void focusInEvent( QFocusEvent* event );
  6.     virtual void focusOutEvent( QFocusEvent* event );
  7.   //more code
  8. };
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Now I would, from the QMainWindow, to execute some code depending on the QWidget having the focus. Now I emit a signal in the focusIn/Out methods so:

Qt Code: 
  1. /*********************************************/
  2. /* focusInEvent                                      
  3. /*********************************************/
  4. void MyWidget::focusInEvent( QFocusEvent *event )
  5. {
  6.     Q_UNUSED(event);
  7.     emit sig_focusIn(); // widget had the focus
  8. }
  9.  
  10. /*********************************************/
  11. /* focusOutEvent                 
  12. /*********************************************/
  13. void MyWidget::focusOutEvent( QFocusEvent *event )
  14. {
  15.     Q_UNUSED(event);
  16.     emit sig_focusOut(); // focus is gone
  17. }
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The signals are connected to a slot that's part of mainwindow class. My code works but I'm not sure if is the best way to achieve what I would.
For example I read about a virtual bool eventFilter(QObject *obj, QEvent *evt); that can filter ( as it says ) the event sent to other widgets. For example intercepting the focus event. The problem is how can I know it the focus is for ww1 or ww2?
I hope to get a reply.
Best Regards,
Franco