RE: Creating a local event loop (modality again...)

[Warrior <ymg azstarnet com>]

On 08-Nov-2000 Federico Heinz shared with us the following piece of wisdom:

> Suppose you have a text entry, where the user can enter
> abbreviations, and the program must expand the abbreviations when the
> user leaves the entry. This is pretty easy, all you must do is
> connect the entry's "focus_out_event" to a handler that replaces the
> abbreviations for the full text.
>
> Now suppose that the abbreviations are not univocal, i.e. it might
> happen that the user enters an abbreviation that matches more than
> one expansion. In that case, I would like to have the program pop up
> a window with the list of potential matches, and let the user decide
> which expansion she meant. If there are more than one ambiguous
> match, the program should pop up the window to let the user select
> which is the right expansion for the first one, then pop it up again
> for the second, and so on.
>
> I'm having real trouble implementing this. The main problem here is
> that the "focus_out_event" handler must create the window, display
> it, and handle this window's user input, and even potentially repeat
> all of this several times BEFORE returning to the main Gtk event
> loop. What this amounts to, basically, is a local event loop for this
> window exclusively, but I haven't been able to figure out how to do
> that yet. I considered using gtk_main_iteration(), but I understand
> that it does busy waiting, and I'm not THAT desperate.
>
> Any pointers on how to go about this? Or even a suggestion for a
> better implementation? I must admit I hate modal windows myself, but
> I seem unable to come up with a better idea.

All right, here's the implementation that works for me (although there might be
better implementations out there, which I'm not aware about):

1. End the function, which creates the modal window with call to gtk_main().
2. In the callback attached to "destroy" signal call gtk_main_quit() after
    destroying the  window.
3. IMPORTANT: Block the "delete_event" signal for this window - callback
    attached to this signal should simply return TRUE.
4. It might be possible to also call gtk_main_quit() from the callback attached
    to "delete_event" instead of doing step #3, but I never tried that and
    don't know if it's gonna work or not.

Hope this helps.

-- 
Bye, Warrior.

ICQ #24496762

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Tagline for Wednesday, November 08, 2000, 17:33
--- Don't Take Life Seriously, It Is Not Permanent.