[gtkmm] trouble with redrawing screen

["B.Hakvoort" <bart hakvoort be>]

Hi,

I'd like to show my impatient users a pulsebar when an application
performs a lenghty task. But somehow the "pulsing" doesn't show up in
the main screen. I've already tried several things like
queue_draw() and 
while (Gtk::Main::events_pending())  Gtk::Main::iteration();

Can someone tell me what i'm doing wrong?

Bart

PS. Attached is a small example, i think its pretty straigthforward.





#include <gtkmm/box.h>
#include <gtkmm/progressbar.h>
#include <gtkmm/statusbar.h>
#include <gtkmm/button.h>
#include <gtkmm/window.h>
#include <gtkmm/main.h>
#include <sigc++/class_slot.h>

class Demo : public Gtk::Window
{
	Gtk::VBox vbox_main;
	Gtk::ProgressBar pulsebar;
	Gtk::Statusbar statusbar;
	Gtk::Button btnTask;
	
	Glib::Thread *pulse_thread;
	bool pulse;

public:	
	
	Demo()
	{
		set_default_size(300,150);
		
		btnTask.set_label( "Perform some task");
		btnTask.signal_clicked().connect( SigC::slot( *this, &Demo::btnTask_clicked ) );
		vbox_main.pack_start(btnTask);
		
		pulsebar.set_pulse_step(0.01);
		statusbar.pack_start( pulsebar );
		vbox_main.pack_end(statusbar, Gtk::PACK_SHRINK);
		
		add(vbox_main);
		show_all_children();
	}
	
	void btnTask_clicked()
	{
		pulse=true;
		pulse_thread = Glib::Thread::create(SigC::slot_class(*this, &Demo::Pulse), true);
		
		sleep(5);//do something which requires an unknown amount of time.....
		
		pulse=false;
		pulse_thread->join();
	}
	
	void Pulse()
	{
		while (pulse) {
			pulsebar.pulse();
			usleep(10000);
		}
	}
	
};



int main(int argc, char *argv[])
{
	Glib::thread_init();
	Gtk::Main kit(argc, argv);
	Demo demo;
    
    Gtk::Main::run(demo);
    
    return 0;
}