QAction-related problems/needs

David Faure faure at
Wed Apr 5 00:14:41 BST 2006

I'm currently trying to implement KOffice's undo/redo action based on QAction (and in kdeui).

That action was a KToolbarPopupAction - i.e. simple menuitem in a menu, but
button with popup in a toolbar - but its particularity is that the popup
doesn't contain usual text-based items, but instead one QListView
(was a QListBox in qt3), so that the user can select multiple items in that listview,
starting from the top. This is used to undo N steps at once. The popup also
has a QLabel at the bottom to show "Undo N actions" while moving the mouse.

So this brings me to the following question: how do I add a widget to a menu?
This doesn't seem to be available; only actions can be added to a menu.
Hmm. Looking at qmenu.cpp ... it's worse than I thought. There are no widgets
at all used internally for every "item"; it's all done by qstyle painting based 
on the action's text and icon :( Probably more efficient, but very unflexible
compared to Qt3's QPopupMenu.
Thiago: I remember a similar request on kde-devel, do you know if a TT task
ended up being created for that? Although now that I see the code I see how
this will never happen...

OK, maybe this means I shouldn't use a popupmenu, but rather create a
widget for the popup (with the Qt::Popup flag) which contains my listview+label.
However for this I need to write an action which pops up such a custom popup,
i.e. not using QToolButton::setPopupMode nor QToolButton::setMenu, since
that is QMenu based.
This means redoing by hand the support for showing a delayed 'popup' from
a toolbutton...

Argl, is there really no better solution?
What used to be doable with one qlistbox subclass in qt3 would now require
- a kaction subclass
- a qlistview subclass
- a qabstractlistmodel subclass
- a qtoolbutton subclass
The first three seem logical, but the latter is killing me; lots of code duplication.
Maybe QToolButton's support for a "popup" could be generalized so that the
popup isn't necessarily a QMenu, but any QWidget? Looking at the code I
see little that actually requires a menu... except for the exec() call, but I guess
the QMenu::exec() code could be done directly in qtoolbutton to "exec" any
Does this make sense, or am I overlooking anything? I guess my next step
is to talk to TT about this and see if they (or I) can generalize QToolButton's
idea of popups...

David Faure, faure at, sponsored by Trolltech to work on KDE,
Konqueror (, and KOffice (

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