example-2.py

Developing with Gnome一书examples例子代码

#!/usr/bin/env python

# This program monitors the
# /apps/nautilus/preferences/always_use_browser,
# /apps/nautilus/preferences/show_image_thumbnails, and
# /apps/nautilus/preferences/thumbnail_limit gconf keys, and allows
# the user to change them as well.

import gtk
import gtk.glade
import gconf
import re

class ExampleWindow:
  def __init__(self, glade_file):
    # Parse the glade file
    self.all_da_widgets = gtk.glade.XML(glade_file)

    # Get the client and tell it we want to monitor /apps/nautilus/preferences
    self.conf_client = gconf.client_get_default()
    self.conf_client.add_dir("/apps/nautilus/preferences", \
                             gconf.CLIENT_PRELOAD_NONE);


    # First, setup the checkbutton for the always_use_browser key 

    # Get the check_button
    self.browser_checkbutton = self.all_da_widgets.get_widget("BrowserMode")

    # Connect the check_button to a callback that can toggle it when the option
    # is changed by some outside program.
    self.conf_client.notify_add(                       \
      "/apps/nautilus/preferences/always_use_browser", \
      self.browser_key_changed                         \
      )

    # Connect the check_button's clicked callback up so that it can change the
    # gconf setting.
    self.browser_checkbutton.connect("clicked", self.browser_key_toggled)

    # Determine whether button should start activated or not
    self.old_browser_setting = \
      self.conf_client.get_bool("/apps/nautilus/preferences/always_use_browser")
    self.browser_checkbutton.set_active(self.old_browser_setting)


    # Second, setup the text entry for the show_image_thumbnails key 

    # Get the Entry
    self.show_thumbnail_entry = \
      self.all_da_widgets.get_widget("ShowThumbnailsEntry")

    # Connect the show thumbnail entry to a callback that can toggle it
    # when the option is changed by some outside program.
    self.conf_client.notify_add(                          \
      "/apps/nautilus/preferences/show_image_thumbnails", \
      self.show_thumbnails_key_changed                    \
      )

    # Connect the show thumbnail entry's activated callback up so that
    # it can change the gconf setting.
    self.show_thumbnail_entry.connect("activate", self.show_thumbnails_modified)

    # Determine the starting value of this key
    self.old_show_thumbnails_setting = \
      self.conf_client.get_string(     \
        "/apps/nautilus/preferences/show_image_thumbnails")
    self.show_thumbnail_entry.set_text(self.old_show_thumbnails_setting)


    # Third, setup the text entry for the thumbnail_limit key

    # Get the Entry
    self.thumbnail_limit_entry = \
      self.all_da_widgets.get_widget("ThumbnailLimitEntry")

    # Connect the thumbnail limit entry to a callback that can toggle
    # it when the option is changed by some outside program.
    self.conf_client.notify_add(
      "/apps/nautilus/preferences/thumbnail_limit",
      self.thumbnail_limit_key_changed
      )

    # Connect the thumbnail limit entry's activated callback up so that
    # it can change the gconf setting.
    self.thumbnail_limit_entry.connect("activate", self.thumbnail_limit_modified)

    # Determine the starting value of this key
    self.old_thumbnail_limit = \
      self.conf_client.get_int("/apps/nautilus/preferences/thumbnail_limit");
    self.thumbnail_limit_entry.set_text(str(self.old_thumbnail_limit));


    # Get the close button and connect it to hide
    close_button = self.all_da_widgets.get_widget("CloseButton")
    close_button.connect("clicked", gtk.mainquit)

    # Get the close button and connect it to hide
    main_window = self.all_da_widgets.get_widget("MainWindow")
    main_window.connect("delete_event", gtk.mainquit)

  def browser_key_changed(self, client, connection_id, entry, args):

    # Make sure the preference has a valid value
    if (entry.get_value().type == gconf.VALUE_BOOL):
      # Get the new value
      new_browser_setting = entry.get_value().get_bool()

      # Try to handle asynchronous-ness of GConf and prevent calling
      # checkbutton_toggled again if this function was called as a
      # result of the self.conf_client.set() function call.
      if (new_browser_setting != self.old_browser_setting):
        self.old_browser_setting = new_browser_setting
        self.browser_checkbutton.set_active(new_browser_setting)

  def browser_key_toggled(self, checkbutton_widget):

    # Determine whether the checkbutton is already set or not
    is_set = self.browser_checkbutton.get_active()
 
    # Try to handle asynchronous-ness of GConf and prevent calling
    # key_changed again if this function was called as a result of the
    # self.checkbutton.set_active() function call.
    if (is_set != self.old_browser_setting):
      self.old_browser_setting = is_set;
      self.conf_client.set_bool("/apps/nautilus/preferences/always_use_browser",\
                                is_set)

  def show_thumbnails_key_changed(self, client, connection_id, entry, args):

    # Make sure the preference has a valid value
    if (entry.get_value().type == gconf.VALUE_STRING):
      # Get the new value
      new_setting = entry.get_value().get_string()

      # Check if it seems valid, give a warning if it doesn't
      if ((new_setting != "always")     and \
          (new_setting != "local_only") and \
          (new_setting != "never")):
        # I couldn't find an equivalent for g_warning
        print "Unrecognized value specified by external program...\n"

      # Use the new value if it's different than the old
      if (new_setting != self.old_show_thumbnails_setting):
        self.old_show_thumbnails_setting = new_setting
        self.show_thumbnail_entry.set_text(new_setting)

  def show_thumbnails_modified(self, show_thumbnail_entry):

    # Get the current value
    cur_value = self.show_thumbnail_entry.get_text()
 
    if ((cur_value == "always")     or
        (cur_value == "local_only") or
        (cur_value == "never")):
      if (cur_value != self.old_show_thumbnails_setting):
        self.old_show_thumbnails_setting = cur_value
        self.conf_client.set_string(
          "/apps/nautilus/preferences/show_image_thumbnails",
          cur_value);
    else:
      # I couldn't find an equivalent for g_warning
      print "This program needs an error window to warn you" + \
            " that you typed an invalid value."
      self.show_thumbnail_entry.set_text(self.old_show_thumbnails_setting)

  def thumbnail_limit_key_changed(self, client, connection_id, entry, args):

    # Make sure the preference has a valid value
    if (entry.get_value().type == gconf.VALUE_INT):
      # Get the new value
      new_value = entry.get_value().get_int()

      # Check if it seems valid, give a warning if it doesn't
      if (new_value < 0):
        # I couldn't find an equivalent for g_warning
        print "Bad value seems to have been set by external program."

      # Use the new value if it's different than the old
      if (new_value != self.old_thumbnail_limit):
        self.old_thumbnail_limit = new_value
        self.thumbnail_limit_entry.set_text(str(new_value))

  def thumbnail_limit_modified(self, thumbnail_limit_entry):

    # Get the current value
    new_value = self.thumbnail_limit_entry.get_text()

    nonnegative_number_regex = re.compile(r'^\d+$')
    if nonnegative_number_regex.match(new_value):
      if (new_value != self.old_thumbnail_limit):
        self.old_thumbnail_limit = new_value
        self.conf_client.set_int("/apps/nautilus/preferences/thumbnail_limit",\
                                 int(new_value))
      
    else:
      # I couldn't find an equivalent for g_warning
      print "This program needs an error window to warn you" + \
            " that you typed an invalid value."
      self.thumbnail_limit_entry.set_text(str(self.old_thumbnail_limit))

# Create the ExampleWindow
window = ExampleWindow("example-2.glade")

# start the event loop
gtk.main()