[Interest] "Loading", recursion and GUI's

[William Hallatt]

OK, got it working with the processEvents() call (no need for GUI
interaction while processing, so went with a static, blocking label
display).  The reason my previous attempts at using this function failed
was because I was calling it in all the wrong places (the *before* hint was
the key).

A QThread implementation will be used for the refactoring.  The current
version is a kind of "proof of concept"/prototype implementation, just to
see if I can make it happen :)

Thanks to everyone for the input!

Kind regards,
William.



On 8 January 2013 10:28, R. Reucher <rene.reucher at batcom-it.net> wrote:

> On Tuesday 08 January 2013 09:15:50 William Hallatt wrote:
> > I have to update the tree widget with each element visited and as far as
> > I'm aware, one cannot use widget classes in separate threads (QThread).
> > You are probably right that I can do that via a signals and slots (thanks
> > for that, I don't know why I didn't think of it, it's rather obvious),
> but
> > won't that "cost" roughly the same?  Each time the recursive function is
> > called, a signal will be emitted telling the GUI to update so how will it
> > be different?
> Well, the major difference is that you're not "blocking" the main thread
> aka
> GUI thread, so it has time for GUI updates.
>
> However, as others already stated, in your specific case a simple
>
> qApp->processEvents();
>
> *before* starting the recursion should actually be sufficient. And if you
> want
> your GUI to be responsive while the recursion runs, you should periodically
> call it again. However, this method will most likely be slower than the
> threaded approach, though much simpler to implement.
>
> HTH, René
> _______________________________________________
> Interest mailing list
> Interest at qt-project.org
> http://lists.qt-project.org/mailman/listinfo/interest
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.qt-project.org/pipermail/interest/attachments/20130108/844133fd/attachment.html>