MessageDialog (Python)

A message dialog which prints messages on the terminal, depending on your choices.

Code used to generate this example

from gi.repository import Gtk
from gi.repository import Gio
import sys


class MyWindow(Gtk.ApplicationWindow):

    # constructor for a window (the parent window) with a label
    def __init__(self, app):
        Gtk.Window.__init__(self, title="GMenu Example", application=app)
        self.set_default_size(400, 200)
        label = Gtk.Label()
        label.set_text("This application goes boom!")
        self.add(label)

        # create the message_action (a Gio.SimpleAction) - for the window
        message_action = Gio.SimpleAction.new("message", None)
        # connect the signal from the action to the function message_cb()
        message_action.connect("activate", self.message_cb)
        # add the action to the application
        app.add_action(message_action)

    # callback function for the signal "activate" from the message_action
    # in the menu of the parent window
    def message_cb(self, action, parameter):
        # a Gtk.MessageDialog
        messagedialog = Gtk.MessageDialog(parent=self,
                                          flags=Gtk.DialogFlags.MODAL,
                                          type=Gtk.MessageType.WARNING,
                                          buttons=Gtk.ButtonsType.OK_CANCEL,
                                          message_format="This action will cause the universe to stop existing.")
        # connect the response (of the button clicked) to the function
        # dialog_response()
        messagedialog.connect("response", self.dialog_response)
        # show the messagedialog
        messagedialog.show()

    def dialog_response(self, widget, response_id):
        # if the button clicked gives response OK (-5)
        if response_id == Gtk.ResponseType.OK:
            print("*boom*")
        # if the button clicked gives response CANCEL (-6)
        elif response_id == Gtk.ResponseType.CANCEL:
            print("good choice")
        # if the messagedialog is destroyed (by pressing ESC)
        elif response_id == Gtk.ResponseType.DELETE_EVENT:
            print("dialog closed or cancelled")
        # finally, destroy the messagedialog
        widget.destroy()


class MyApplication(Gtk.Application):

    def __init__(self):
        Gtk.Application.__init__(self)

    def do_activate(self):
        win = MyWindow(self)
        win.show_all()

    def quit_cb(self, action, parameter):
        self.quit()

    def do_startup(self):
        Gtk.Application.do_startup(self)

        # create a menu (a Gio.Menu)
        menu = Gio.Menu()
        # append a menu item with label "Message" and action "app.message"
        menu.append("Message", "app.message")
        # append a menu item with label "Quit" and action "app.quit"
        menu.append("Quit", "app.quit")
        # set menu as the menu for the application
        self.set_app_menu(menu)

        # a new simpleaction - for the application
        quit_action = Gio.SimpleAction.new("quit", None)
        quit_action.connect("activate", self.quit_cb)
        self.add_action(quit_action)

app = MyApplication()
exit_status = app.run(sys.argv)
sys.exit(exit_status)

Useful methods for a MessageDialog widget

In line 18 the signal "activate" is connected to the callback function message_cb() using widget.connect(signal, callback function). See for a more detailed explanation.

In the constructor of MessageDialog we could set flags as Gtk.DialogFlags.DESTROY_WITH_PARENT (to destroy the messagedialog window when its parent window is destroyed) or as Gtk.DialogFlags.MODAL (no interaction with other windows of the application).

In the constructor of MessageDialog we could set type as any of Gtk.MessageType.INFO, Gtk.MessageType.WARNING, Gtk.MessageType.QUESTION, Gtk.MessageType.ERROR, Gtk.MessageType.OTHER depending on what type of message we want.

In the constructor of MessageDialog we could set buttons as any of Gtk.ButtonsType.NONE, Gtk.ButtonsType.OK, Gtk.ButtonsType.CLOSE, Gtk.ButtonsType.CANCEL, Gtk.ButtonsType.YES_NO, Gtk.ButtonsType.OK_CANCEL, or any button using add_button() as in Gtk.Dialog.

We could substitute the default image of the MessageDialog with another image using


image = Gtk.Image()
image.set_from_stock(Gtk.STOCK_CAPS_LOCK_WARNING, Gtk.IconSize.DIALOG)
image.show()
messagedialog.set_image(image)

where Gtk.STOCK_CAPS_LOCK_WARNING is any image from Stock Items. We could also set any image as in the Image widget, as image.set_from_file("filename.png").

format_secondary_text("some secondary message") sets a secondary message. The primary text becomes bold.

API-Referenzen

In this sample we used the following:

GtkMessageDialog

GtkDialog

GtkWindow

GSimpleAction

GActionMap

GMenu

GtkApplication