Stand-alone

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Run program as GtkApplication

GtkApplication handles different important aspects of a GTK+ application like GTK+ initialization, session management and desktop integration.

/images/14_application.thumbnail.png

XML files

Glade

Glade is used as usual, main windows should be **GtkApplicationWindows*. As example the file from the dialogue article is reused.

System Message: WARNING/2 (<string>, line 17); backlink

Inline strong start-string without end-string.

GMenu

The GNOME Shell supports appmenus residing in the (top) panel. The Gmenu XML file must be formatted to be recognized as GioMenu:

<?xml version="1.0"?>
<interface>
 <menu id="appmenu">
    <section>
      <item>
        <attribute name="label" translatable="yes">Menu Item</attribute>
        <attribute name="action">app.item</attribute>
      </item>
    </section>
  </menu>
</interface>

Glade identifies this file format as an outdated Glade file and refuses to open it. Apart from that GtkBuilder can handle the menu and address identifiers.

Python

Initialize GtkApplication

The initialization process requires the parameters application_id and flags. Flags can normally set to 0 being the same as FLAGS_NONE (see Gio.ApplicationFlags), naming conventions for application_id are listed here.

The application can be connected to different signals being emitted on preassigned events. It is mandatory to at least define an activate signal:

def __init__(self):

    self.app = Gtk.Application.new("org.application.test", 0)
    #self.app.connect("startup", self.on_app_startup) #optional
    self.app.connect("activate", self.on_app_activate)
    #self.app.connect("shutdown", self.on_app_shutdown) #optional

def on_app_activate(self, app):

    #setting up GtkBuilder etc.
    ...
    ...
    ...

Appmenu

GMenu XML files are loaded by GtkBuilder:

builder.add_from_file("menu.ui")
app.set_app_menu(builder.get_object("appmenu"))

Menu entries now have to be connected to actions which are created as GioSimpleActions:

def add_simple_action(self, name, callback):
    action = Gio.SimpleAction.new(name)
    action.connect("activate", callback)
    self.app.add_action(action)

In the example file actions invokes dialog windows.

Start and quit

GtkApplication takes over the handling of the GTK+ mainloop so there is no need of starting and quitting GTK+ manually and run() and quit() called instead:

Gtk.main()      ->  app.run(argv)
Gtk.main_quit() ->  app.quit()

If the application is quit by the [X] button or the "Quit" appmenu entry the "shutdown" signal is emitted (see above) and the program is terminated. That means there is no need to define these signals like in previous examples using GtkWindow. The "shutdown" also works even if the signal is not explicitly connected to a function during the initialization process.

Listings

Glade

13_dialoge.glade (Source)

<?xml version="1.0" encoding="UTF-8"?>
<!-- Generated with glade 3.20.0 -->
<interface>
  <requires lib="gtk+" version="3.20"/>
  <object class="GtkApplicationWindow" id="window">
    <property name="can_focus">False</property>
    <property name="title" translatable="yes">Titel</property>
    <signal name="destroy" handler="on_window_destroy" swapped="no"/>
    <child>
      <object class="GtkBox">
        <property name="visible">True</property>
        <property name="can_focus">False</property>
        <property name="orientation">vertical</property>
        <child>
          <object class="GtkButton" id="aboutbutton">
            <property name="label" translatable="yes">GtkAboutDialog</property>
            <property name="visible">True</property>
            <property name="can_focus">True</property>
            <property name="receives_default">True</property>
            <signal name="clicked" handler="on_aboutbutton_clicked" swapped="no"/>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">0</property>
          </packing>
        </child>
        <child>
          <object class="GtkButton" id="messagebutton">
            <property name="label" translatable="yes">GtkMessageDialog</property>
            <property name="visible">True</property>
            <property name="can_focus">True</property>
            <property name="receives_default">True</property>
            <signal name="clicked" handler="on_messagebutton_clicked" swapped="no"/>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">1</property>
          </packing>
        </child>
      </object>
    </child>
    <child type="titlebar">
      <placeholder/>
    </child>
  </object>
  <object class="GtkAboutDialog" id="aboutdialog">
    <property name="can_focus">False</property>
    <property name="type_hint">dialog</property>
    <property name="transient_for">window</property>
    <property name="attached_to">window</property>
    <property name="program_name">Glade-Tutorial</property>
    <property name="version">1.0</property>
    <property name="logo_icon_name">help-about</property>
    <property name="license_type">mit-x11</property>
    <signal name="delete-event" handler="on_dialog_delete_event" swapped="no"/>
    <signal name="response" handler="on_dialog_response" swapped="no"/>
    <child internal-child="vbox">
      <object class="GtkBox">
        <property name="can_focus">False</property>
        <property name="orientation">vertical</property>
        <property name="spacing">2</property>
        <child internal-child="action_area">
          <object class="GtkButtonBox">
            <property name="can_focus">False</property>
            <property name="layout_style">end</property>
            <child>
              <object class="GtkButton" id="button1">
                <property name="label">gtk-ok</property>
                <property name="visible">True</property>
                <property name="can_focus">True</property>
                <property name="receives_default">True</property>
                <property name="use_stock">True</property>
              </object>
              <packing>
                <property name="expand">True</property>
                <property name="fill">True</property>
                <property name="position">1</property>
              </packing>
            </child>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">False</property>
            <property name="position">0</property>
          </packing>
        </child>
      </object>
    </child>
    <action-widgets>
      <action-widget response="-8">button1</action-widget>
    </action-widgets>
    <child type="titlebar">
      <placeholder/>
    </child>
  </object>
  <object class="GtkMessageDialog" id="messdialog">
    <property name="can_focus">False</property>
    <property name="type_hint">dialog</property>
    <property name="transient_for">window</property>
    <property name="buttons">yes-no</property>
    <property name="text" translatable="yes">&lt;b&gt;MessageDialog schließen?&lt;/b&gt;</property>
    <property name="use_markup">True</property>
    <signal name="response" handler="on_dialog_response" swapped="no"/>
    <child internal-child="vbox">
      <object class="GtkBox">
        <property name="can_focus">False</property>
        <property name="orientation">vertical</property>
        <property name="spacing">2</property>
        <child internal-child="action_area">
          <object class="GtkButtonBox">
            <property name="can_focus">False</property>
            <property name="homogeneous">True</property>
            <property name="layout_style">end</property>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">False</property>
            <property name="position">0</property>
          </packing>
        </child>
      </object>
    </child>
    <child type="titlebar">
      <placeholder/>
    </child>
  </object>
</interface>

GMenu

14_giomenu.ui (Source)

<?xml version="1.0"?>
<interface>
  <menu id="appmenu">
    <section>
      <item>
        <attribute name="label" translatable="yes">About</attribute>
        <attribute name="action">app.about</attribute>
      </item>
      <item>
        <attribute name="label" translatable="yes">Message</attribute>
        <attribute name="action">app.message</attribute>
      </item>
    </section>
    <section>
      <item>
        <attribute name="label" translatable="yes">Quit</attribute>
        <attribute name="action">app.quit</attribute>
        <attribute name="accel">&lt;Primary&gt;q</attribute>
      </item>
    </section>
  </menu>
</interface>

Python

14_application.py (Source)

#!/usr/bin/python
# -*- coding: utf-8 -*-

import sys
import gi
gi.require_version('Gtk','3.0')
from gi.repository import Gtk, Gio

class Handler:

    def on_window_destroy(self,window):
        window.close()

    def on_dialog_delete_event(self,widget,event):
        widget.hide_on_delete()
        return True

    def on_aboutbutton_clicked(self,widget):
        app.obj("aboutdialog").show_all()

    def on_messagebutton_clicked(self,widget):
        app.obj("messdialog").format_secondary_text("")
        app.obj("messdialog").show_all()

    def on_dialog_response(self,widget,response):
        if response == -8:
            widget.hide_on_delete()
        elif response == -9:
            widget.format_secondary_text("Doch!")

class ExampleApp:

    def __init__(self):

        self.app = Gtk.Application.new("org.application.test", Gio.ApplicationFlags(0))
        self.app.connect("startup", self.on_app_startup)
        self.app.connect("activate", self.on_app_activate)
        self.app.connect("shutdown", self.on_app_shutdown)

    def on_app_startup(self, app):
        print("Gio.Application startup signal emitted")

    def on_app_activate(self, app):
        print("Gio.Application activate signal emitted")
        builder = Gtk.Builder()
        builder.add_from_file("13_dialoge.glade")
        builder.add_from_file("14_giomenu.ui")
        builder.connect_signals(Handler())

        app.set_app_menu(builder.get_object("appmenu"))
        self.obj = builder.get_object
        self.obj("window").set_application(app)

        #display application name in upper panel of the GNOME Shell
        self.obj("window").set_wmclass("Application test","Application test")
        self.obj("window").show_all()

        self.add_simple_action("about", self.on_action_about_activated)
        self.add_simple_action("message", self.on_action_message_activated)
        self.add_simple_action("quit", self.on_action_quit_activated)

    def on_app_shutdown(self, app):
        print("Gio.Application shutdown signal emitted")

    def add_simple_action(self, name, callback):
        action = Gio.SimpleAction.new(name)
        action.connect("activate", callback)
        self.app.add_action(action)

    def on_action_about_activated(self, action, user_data):
        self.obj("aboutdialog").show_all()

    def on_action_message_activated(self, action, user_data):
        Handler().on_messagebutton_clicked(self)

    def on_action_quit_activated(self, action, user_data):
        self.app.quit()

    def run(self, argv):
        self.app.run(argv)

app = ExampleApp()
app.run(sys.argv)
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