Re: Gtk ProgressBar problem

[Tristan Van Berkom <vantr touchtunes com>]

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