image indicator with glade

import hal_glib
import hal
import gtk # for image references

# boiler code to register our handler
def get_handlers(halcomp,builder,useropts):
    return [HandlerClass(halcomp,builder,useropts)]

class HandlerClass:
    def __init__(self, halcomp,builder,useropts):
        example_trigger = hal_glib.GPin(halcomp.newpin('hal_image1', hal.HAL_BIT, hal.HAL_IN))
        example_trigger.connect('value-changed', self._on_example_trigger_change)
        self.hal_image1 = builder.get_object('hal_image1') # the glade file's image must be the same as this.

    def _on_example_trigger_change(self,pin,userdata=None):
        print "pin value changed to:%d" % (pin.get())
        if pin.get():
            self.hal_image1.set_from_stock(gtk.STOCK_APPLY,gtk.ICON_SIZE_LARGE_TOOLBAR)
        else:
            self.hal_image1.set_from_stock(gtk.STOCK_CANCEL,gtk.ICON_SIZE_LARGE_TOOLBAR)

'''
This file demonstrate how to change a gladevcp picture with a created
hal pin.
notes:
- the handler is linked to "image1" of gladevcp
- to set a filename of a picture the image1 must have the filename opion activated
- the files error_0.png, error_0.png, error_0.png must exist
'''

#---import the needed librarys---
import hal
import glib
import hal_glib
import time
from inspect import stack


#---create a variable with filenames that can be loaded index---
error_files  = ( "./Gui/error_0.png", 
                 "./Gui/error_1.png",
                 "./Gui/error_2.png")
          

#---python code that is not associated with gladevcp ui's---
class OtherClass:

    #---???---	
    def invisible(selfself):
        pass


class HandlerClass:

    #---button press event---
    def on_button_press(self,widget,data=None):
        '''only if button is used'''

    #---hal pin "message" change event---
    def _on_message_change(self,hal_pin,data=None):

        #---set the filename from gladevcp image1 with the value on "message" pin--- 
        self.builder.get_object('image1').set_from_file( error_files[ self.halcomp['message'] ] )


    #---startup procedure---
    def __init__(self, halcomp,builder,useropts):

        #---init halcomp/ builder---        
	self.halcomp = halcomp
        self.builder = builder

        #---create a new halpin to choose an image---
        self.example_trigger = hal_glib.GPin(halcomp.newpin('message',  hal.HAL_U32, hal.HAL_IN))
	
        #---assign the message pin to the _on_message_change event---
        self.example_trigger.connect('value-changed', self._on_message_change)

#---???---
other = OtherClass() 

#---connect this handler to gladevcp instances---
def get_handlers(halcomp,builder,useropts):
    return [HandlerClass(halcomp,builder,useropts)]