MainWindow.py (Código)

# -*- coding: utf-8 -*-
"""Python e GTK 4: PyGObject Gtk.CheckButton()."""
import gi
gi.require_version(namespace='Gtk', version='4.0')
from gi.repository import Gio, Gtk
class MainWindow(Gtk.ApplicationWindow):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.set_title(title='Python e GTK 4: PyGObject Gtk.CheckButton()')
        # Tamanho inicial da janela.
        self.set_default_size(width=1366 / 2, height=768 / 2)
        # Tamanho minimo da janela.
        self.set_size_request(width=1366 / 2, height=768 / 2)
        vbox = Gtk.Box.new(orientation=Gtk.Orientation.VERTICAL, spacing=12)
        vbox.set_homogeneous(homogeneous=True)
        # No GTK 3: set_border_width().
        vbox.set_margin_top(margin=12)
        vbox.set_margin_end(margin=12)
        vbox.set_margin_bottom(margin=12)
        vbox.set_margin_start(margin=12)
        # Adicionando o box na janela principal.
        # No GTK 3: add().
        self.set_child(child=vbox)
        check_button = Gtk.CheckButton.new_with_label(label='Aceitar?')
        check_button.connect('toggled', self.on_check_button_toggled)
        vbox.append(child=check_button)
    def on_check_button_toggled(self, widget):
        if widget.get_active():
            print('Botão marcado')
        else:
            print('Botão desmarcado')
class Application(Gtk.Application):
    def __init__(self):
        super().__init__(application_id='br.natorsc.Exemplo',
                         flags=Gio.ApplicationFlags.FLAGS_NONE)
    def do_startup(self):
        Gtk.Application.do_startup(self)
    def do_activate(self):
        win = self.props.active_window
        if not win:
            win = MainWindow(application=self)
        win.present()
    def do_shutdown(self):
        Gtk.Application.do_shutdown(self)
if __name__ == '__main__':
    import sys
    app = Application()
    app.run(sys.argv)