Choose a file from folder using "file chooser button" or other widget

/home/pc/linuxcnc-dev/bin/gladevcp:298: GtkWarning: gtk_widget_size_allocate(): attempt to allocate widget with width -5 and height 17
  gtk.main()
/home/pc/linuxcnc-dev/bin/gladevcp:298: GtkWarning: GdkWindow 0x4e00003 unexpectedly destroyed
  gtk.main()
Traceback (most recent call last):
  File "./hitcounter-modifyed.py", line 31, in on_notebook1_destroy
    self.ini.save_state(self)
AttributeError: HandlerClass instance has no attribute 'ini'
task: main loop took 0.012469 seconds
**** GLADE VCP ERROR:    X Protocol Error: 3
Shutting down and cleaning up LinuxCNC...
task: 13845 cycles, min=0.000005, max=0.012469, avg=0.001055, 1 latency excursions (> 10x expected cycle time of 0.001000s)
Note: Using POSIX realtime

import hal
import glib
import time
import gtk
import gtk.glade
import gobject
import os



class HandlerClass:
    '''
    class with gladevcp callback handlers
    '''

    def on_button_press(widget,data=None):

        '''
        a callback method
        parameters are:
            the generating object instance, likte a GtkButton instance
            user data passed if any - this is currently unused but
            the convention should be retained just in case
        '''
        print "on_button_press called"
        self.nhits += 1
        self.builder.get_object('hits').set_label("Hits: %d" % (self.nhits))


    def on_notebook1_destroy(self,obj,data=None):
        self.ini.save_state(self)



    def __init__(self, halcomp,builder,useropts):

        '''
        Handler classes are instantiated in the following state:
        - the widget tree is created, but not yet realized (no toplevel window.show() executed yet)
        - the halcomp HAL component is set up and the widhget tree's HAL pins have already been added to it
        - it is safe to add more hal pins because halcomp.ready() has not yet been called at this point.

        after all handlers are instantiated in command line and get_handlers() order, callbacks will be
        connected with connect_signals()/signal_autoconnect()

        The builder may be either of libglade or GtkBuilder type depending on the glade file format.
        '''

        self.halcomp = halcomp
        self.builder = builder
        self.nhits = 0

        builder.get_object('vcp_filechooserbutton1').set_current_folder(os.path.expanduser('/home/pc/F1/'))
        builder.get_object('vcp_filechooserbutton2').set_current_folder(os.path.expanduser('/home/sara/pc/F2/'))


def get_handlers(halcomp,builder,useropts):
    '''
    this function is called by gladevcp at import time (when this module is passed with '-u <modname>.py')

    return a list of object instances whose methods should be connected as callback handlers
    any method whose name does not begin with an underscore ('_') is a  callback candidate

    the 'get_handlers' name is reserved - gladevcp expects it, so do not change
    '''


    return [HandlerClass(halcomp,builder,useropts)]