Continuing with the series of tutorials about pygtk. This one covers the development of a simple application with a progress bar that advances every second, showing the time elapsed as the progress bar moves. In this tutorial, since a process that can freeze the window is run, threads are used to avoid it; in addition, it shows the use of toggle buttons to control the progress bar.

The figure shows the design of the application.

The code is shown below:

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#       sin ej6.py
#       
#       Copyright 2009 Ernesto Nadir Crespo Avila 
#       
#       This program is free software; you can redistribute it and/or modify
#       it under the terms of the GNU General Public License as published by
#       the Free Software Foundation; either version 2 of the License, or
#       (at your option) any later version.
#       
#       This program is distributed in the hope that it will be useful,
#       but WITHOUT ANY WARRANTY; without even the implied warranty of
#       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#       GNU General Public License for more details.
#       
#       You should have received a copy of the GNU General Public License
#       along with this program; if not, write to the Free Software
#       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
#       MA 02110-1301, USA.
#Importar los módulos gtk, time, threading, thread, gobject
import gtk, time
import threading
import thread
import gobject
#Iniciando el hilo sin usarlo
gtk.gdk.threads_init()



#La clase App hereda threading.Thread
class App(threading.Thread):
    def __init__(self):
     #Método constructor, asociando los widgets
        self.glade_file = "ej6.ui"
        self.glade = gtk.Builder()
        self.glade.add_from_file(self.glade_file)
        self.window1 = self.glade.get_object('window1')
        self.togglebutton1 = self.glade.get_object('togglebutton1')
        self.button1 = self.glade.get_object('button1')
        self.progressbar1 = self.glade.get_object('progressbar1')
        self.new_val = 0.0
        self.rango =60
     #Definiendo el valor inicial de la barra de proceso, definiendo los saltos en 0.1
        self.progressbar1.set_fraction(self.new_val)
        self.progressbar1.set_pulse_step(0.1)
        self.window1.connect("destroy",self.on_window1_destroy)
        self.button1.connect('clicked', self.on_button1_clicked)
        self.togglebutton1.connect('toggled',self.on_togglebutton1_toggled)
        #Iniciando el hilo en el constructor
     threading.Thread.__init__(self)
        self.window1.show_all()




    def __iteracion__(self):
     #Iteración en segundos cambiando el valor en la barra de progreso.
        for i in range(self.rango):
            if self.togglebutton1.get_active() == True:
                self.new_val = self.progressbar1.get_fraction() + 0.01
                if self.new_val > 1.0:
                    self.new_val = 0.0
                    self.togglebutton1.set_active(False)
                    break
                else:
                    time.sleep(1)
                    self.x = self.new_val*100
                    self.progressbar1.set_text("%s" %self.x)
                    self.progressbar1.set_fraction(self.new_val)
            else:
                return





    def on_togglebutton1_toggled(self,*args):
     #Si cambia el evento en el boton biestado se inicia la iteración entre los hilos.
        variable = self.togglebutton1.get_active()
        self.rango = 100
        if variable == True:
            lock =  thread.allocate_lock()
            lock.acquire()
            thread.start_new_thread( self.__iteracion__, ()) 
            lock.release()
        else:
         #Se detiene la barra de progreso
            self.progressbar1.set_fraction(self.new_val)
            self.progressbar1.set_text("%s" %self.x)
            return




    def on_window1_destroy(self,*args):
     #Se cierra la aplicación
        gtk.main_quit()

    def on_button1_clicked(self,*args):
     #Se cierra la aplicación al darle clip al boton salir.
        gtk.main_quit()


    def main(self):
     #Inicia la aplicación
        gtk.main()






if __name__ == '__main__':
    app = App()
    app.main()

The following figure shows the application:

===

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