Source code of gnome-pavucontrol-applet.py:

#!/usr/bin/env python
import pygtk
import sys
pygtk.require('2.0')

import gtk
import gnomeapplet

import subprocess
import os, signal
import time

p='NULL'

def sample_factory(applet, iid):
button = gtk.Button()
button.set_relief(gtk.RELIEF_NONE)
button.set_label("Sound Preferences")
button.connect("button_press_event", showPreferences, applet)
applet.add(button)
applet.show_all()

return gtk.TRUE

def showPreferences(widget, event, applet):
global p
if event.type == gtk.gdk.BUTTON_PRESS and event.button == 1:
widget.emit_stop_by_name("button_press_event")
p=subprocess.Popen('pavucontrol')

def destroy(self):
global p
if sys.version_info > (2, 6):
p.terminate()
gtk.main_quit()

if len(sys.argv) == 2 and sys.argv[1] == "run-in-window":
main_window = gtk.Window(gtk.WINDOW_TOPLEVEL)
main_window.set_title("Pavucontrol Applet")
main_window.connect("destroy", destroy)
app = gnomeapplet.Applet()
sample_factory(app, None)
app.reparent(main_window)
main_window.show_all()
gtk.main()
sys.exit()

if __name__ == '__main__':
print "Starting factory"
gnomeapplet.bonobo_factory("OAFIID:GNOME_PavucontrolApplet_Factory", gnomeapplet.Applet.__gtype__, "pavucontrol", "0", sample_factory)