MainWindow.py (Código)

# -*- coding: utf-8 -*-
"""Gtk.Paned() horizontal."""
import gi
gi.require_version(namespace='Gtk', version='3.0')
from gi.repository import Gio, Gtk
class MainWindow(Gtk.ApplicationWindow):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.set_title(title='Gtk.Paned horizontal')
        self.set_default_size(width=1366 / 2, height=768 / 2)
        self.set_position(position=Gtk.WindowPosition.CENTER)
        self.set_default_icon_from_file(filename='../../assets/icons/icon.png')
        paned = Gtk.Paned.new(orientation=Gtk.Orientation.HORIZONTAL)
        paned.set_wide_handle(wide=True)
        paned.set_border_width(border_width=12)
        self.add(widget=paned)
        vbox1 = Gtk.Box.new(orientation=Gtk.Orientation.VERTICAL, spacing=6)
        paned.pack1(child=vbox1, resize=False, shrink=False)
        vbox2 = Gtk.Box.new(orientation=Gtk.Orientation.VERTICAL, spacing=6)
        paned.pack2(child=vbox2, resize=False, shrink=False)
        # vbox1.
        for n in range(1, 4):
            button = Gtk.Button.new_with_label(label=f'Botão {n}')
            vbox1.add(widget=button)
        # vbox2
        for n in range(4, 7):
            button = Gtk.Button.new_with_label(label=f'Botão {n}')
            vbox2.add(widget=button)
        self.show_all()
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)