Re: UIManager and dynamic menus

[Paul Davis <paul linuxaudiosystems com>]

On Wed, 2007-04-04 at 11:27 -0500, Paul Davis wrote:
> Hi list,
> 
> I've been working with UIManager quite a bit lately and I've come up
> against two issues that are fairly related.
> 
> What is the 'UIManager' way of having dynamic menus. I need this when
> adding a list of recent documents to the File menu or when creating a
> list of windows for a View menu.
> 
> I've looked at the merge operations presented by UIManager, but they
> appear to be a bit heavier weight than I would expect for something
> like this.
> 
> If this merge/unmerge functionality is the way to go, does someone
> have a good example of doing this.  I'm fairly certain I get the
> basics, but having a good example is always nice too.

if one of us hasn't been there already, i'm not sure what we would do :)

personally, i have found it *extremely* hard to use the UIManager for
dynamic menus. the problems have been subtle, and i gave up. my approach
now is to use UIManager for the static menus (including a dangling menu
item where the dynamic one will be "hung"), and then do this:

Gtk::Menu*
SequencerUI::get_trigger_submenu ()
{
	Widget* foo = ActionManager::get_widget ("/Main/Triggers/Edit");
	Gtk::MenuItem* foomi = dynamic_cast<MenuItem*>(foo);
	return foomi->get_submenu ();
}

after that, i use the very nice Menu_Helpers function to rebuild the
item list for the return menu (including a clear):

int
SequencerUI::add_trigger_item (Trigger &trigger)
{
	using namespace Menu_Helpers;
	Gtk::Menu* trigger_menu = get_trigger_submenu();
	MenuList& trigger_list = trigger_menu->items();

	trigger_list.push_back (MenuElem (trigger.name().c_str(), bind (mem_fun
(*this, &SequencerUI::edit_trigger), &trigger)));
	trigger_list.back().set_data ("trigger_ptr", &trigger);

	return 0;
}

void
SequencerUI::rebuild_trigger_submenu ()
{
	using namespace Menu_Helpers;
	Gtk::Menu* trigger_menu = get_trigger_submenu();
	MenuList& items = trigger_menu->items();

	items.clear ();

	_sequencer->foreach_trigger (*this, &SequencerUI::add_trigger_item);

	trigger_menu->show_all ();
}

i just couldn't figure out a way to smoothly accomplish the same thing
with readable and grokkable code.

--p