Peculiar behavior trying to set active menu item

[Charles]

Looking at the source, I guess the highlight does not persist because
setCurrentAction calls QMenuPrivate::setCurrentAction using
SelectedFromElsewhere as the reason parameter. On the other hand if I
select the menu item using the keyboard, the highlight persists.

So another option is to select the menu item by simulating keypress:

def _highlight_action(self, target):
    actions = self.actions()
    active = self.activeAction()
    n = actions.index(target) - actions.index(active) if active else
actions.index(target) + 1
    key = Qt.Key.Key_Up if n < 0 else Qt.Key.Key_Down
    for _ in range(abs(n)):
        self.keyPressEvent(QKeyEvent(QEvent.Type.KeyPress, key,
Qt.KeyboardModifier.NoModifier))
    if target.menu():
        self.keyPressEvent(QKeyEvent(QEvent.Type.KeyPress,
Qt.Key.Key_Enter, Qt.KeyboardModifier.NoModifier))


On Thu, Mar 6, 2025 at 9:36 AM John Sturtz <john at sturtz.org> wrote:

> ------ Original Message ------
> From "Charles" <peacech at gmail.com>
> To "John Sturtz" <john at sturtz.org>
> Cc pyqt at riverbankcomputing.com
> Date 3/5/2025 7:15:55 PM
> Subject Re: Peculiar behavior trying to set active menu item
>
> If you look at
> https://codebrowser.dev/qt6/qtbase/src/widgets/widgets/qmenu.cpp.html#_ZN5QMenu10timerEventEP11QTimerEvent,
> QMenu has a timerEvent. This resets the highlight.
>
> What you can do is store the active item in an attribute and reselect it
> after the timerEvent
>
> def timerEvent(self, event):
>         super().timerEvent(event)
>         if self._active_action:
>             self.setActiveAction(self._active_action)
>
> Without having looked at the source, I was already coming to that
> conclusion.  The time duration before the highlight disappeared was so
> consistent, it felt like it must be controlled by a timer.
>
> So I installed an event filter on the menu, and sure enough, shortly after
> typing 'A' to select the first menu item, the menu receives a Timer
> event, followed by an UpdateRequest event.
>
> It isn't obvious to me why it does this.  Indeed, if I just suppress it:
>
>     def timerEvent(self, event):
>         return
>
> it seems to work fine.  But I expect someone must have thought there was a
> good reason for it at some point, and I imagine if I took this approach, it
> would probably eventually bite me somehow.
>
> Another possible approach is to query the active action from timerEvent() and
> save it, prior to calling super() (which I presumes is responsible for
> the reset), then use that to reselect it afterward:
>
>     def timerEvent(self, event):
>         active_action = self.activeAction()
>         super().timerEvent(timer)
>         self.setActiveAction(active_action)
>
> This seems to work also.
>
> Thank you again for your help!
>
> /John
>
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