public class MyApplication : Gtk.Application {

	Gtk.ProgressBar progress_bar;

	protected override void activate () {

		var window = new Gtk.ApplicationWindow (this);

		window.set_title ("ProgressBar Example");

		window.set_default_size (220, 20);

		progress_bar = new Gtk.ProgressBar ();

		window.add (progress_bar);

		window.show_all ();

		double fraction = 0.0;

		progress_bar.set_fraction (fraction);

		GLib.Timeout.add (500, fill);

	}

	bool fill () {

		double fraction = progress_bar.get_fraction (); //get current progress

		fraction += 0.1; //increase by 10% each time this function is called

		progress_bar.set_fraction (fraction);

		/* This function is only called by GLib.Timeout.add while it returns true; */

		if (fraction < 1.0)

			return true;

		return false;

	}

}

public int main (string[] args) {

	var progress_bar_application = new MyApplication ();

	int status =  progress_bar_application.run (args);

	return status;

}