在所有情况下将keyPressEvent分配给顶级QWidget

Question

I am working on an application where I want a certain keystroke (lets say the Tab key for this example) to always be handled by a particular QWidget . Lets say I have a hierarchy like this:

QWidget (top level window)
  ¬ QWidget X (the widget that should handle all Tab presses)
  ¬ QWidget (inner widget)
    ¬ ...
      ¬ ...
        ¬ QLineEdit (very deep into the hierarchy)

The QLineEdit currently has focus, and you can enter text into it. When the user presses Tab , I want it to be handled by QWidget X (near the very top of the hierarchy), to perform some action. How can I make sure a particular QWidget intercepts every single Tab key press if anything in the current window has focus?

Installing an event filter on every child QWidget is impractical, as the application is vast and liable to change.

Answer 1

Instead of having your QWidget override keyPressEvent , you can use QShortcut :

QShortcut *Shortcut = new QShortcut(this);
Shortcut->setKey(Qt::Key_Tab);
connect(Shortcut, SIGNAL(activated()), this, SLOT(TabPressed()));

And then in the TabPressed() slot, perform the action. This works regardless of any another QWidget having focus.