Re: Gtk ProgressBar problem

[Todd Fisher <taf2 lehigh edu>]

Tristan Van Berkom wrote:

> christophe meyer wrote:
>
> > Hi all,
> > In my glade designed project i need to update a progressbar when a 
> > callback function is called like in this short example:
> >
> > void on_button_clicked (GtkButton * button, gpointer user_data)
> > {
> >    GtkWidget *Progress_Bar = lookup_widget (GTK_WIDGET (button), 
> > "progressbar");
> >
> >    action_function1();
> >    gtk_progress_bar_set_fraction (GTK_PROGRESS_BAR (Progress_Bar), 0.2);
> >    action_function2();
> >    gtk_progress_bar_set_fraction (GTK_PROGRESS_BAR (Progress_Bar), 0.4);
> >    action_function3();
> >    gtk_progress_bar_set_fraction (GTK_PROGRESS_BAR (Progress_Bar), 0.6);
> >    action_function4();
> >    gtk_progress_bar_set_fraction (GTK_PROGRESS_BAR (Progress_Bar), 0.8);
> >    action_function5();
> >    gtk_progress_bar_set_fraction (GTK_PROGRESS_BAR (Progress_Bar), 1.0);
> > }
> >
> > Each action_function() takes 2 or 3 seconds to finish.
> > The matter is that when the callback function is called, nothing 
> > happens between the action_functions() with the bar, and at the end, 
> > once action_function5() is finished the progressbar updates directly 
> > to 100%.
> > Home can i gradualy update my progressbar while executing my callback 
> > function ?
>
>
> while (gtk_events_pending()) gtk_main_iteration_do(FALSE);
>
> This pretty line of code will process all gtk pending events by
> nesting the mainloop (as opposed to simply returning to it).
>
> You could go about this in a number of ways, here are a few:
>  - you could start a timout func that calls your action_func() once every
>    timout and then you wouldn't need to nest the main loop
>  - you could insert that handy afore mentioned line between 
> action_func()s
>  - if you want to be really meticulous and have your UI responsive
>    *during* the action func's, then you could use threads.
>  - if you want your ui to stay responsive but want to avoid the trouble
>    and/or complexity that comes with using threads, then you could 
> open up
>    action_func.c and scatter that afore mentioned handy line all over 
> the place.
>
> Cheers,
>                               -Tristan
Hi,

Here's an example I put together to help myself understand how to use 
threads and
progressbars together.  Hopefully, it will help you too :-)

http://severna.homeip.net/source/examples/progress-5-21-2004.tar.gz

-todd