from gi.repository import Gtk


class MainWindow(Gtk.Window):

    def __init__(self):
        Gtk.Window.__init__(self, title="Dialog Example")
        self.set_default_size(200, 100)
        self.set_border_width(30)

        button = Gtk.Button("Open a PopUp")
        button.connect("clicked", self.button_clicked)
        self.add(button)

    def button_clicked(self, widget):
        dialog = PopUp(self)

        # User can't interact with main window until dialog returns something
        response = dialog.run()

        if response == Gtk.ResponseType.OK:
            print("You clicked the OK button")
        elif response == Gtk.ResponseType.CANCEL:
            print("You clicked the CANCEL button")

        dialog.destroy()


class PopUp(Gtk.Dialog):

    def __init__(self, parent):

        # self, title, parent, flags (MODAL prevent interaction with main window until dialog returns), buttons
        Gtk.Dialog.__init__(self, "PopUp Title", parent, Gtk.DialogFlags.MODAL,
                            ("Custom cancel text", Gtk.ResponseType.CANCEL,
                             Gtk.STOCK_OK, Gtk.ResponseType.OK))
        self.set_default_size(200, 100)
        self.set_border_width(10)

        # Content area (area above buttons)
        area = self.get_content_area()
        area.add(Gtk.Label("Wow that's so amazing, you can open a pop up."))
        self.show_all()


win = MainWindow()
win.connect("delete-event", Gtk.main_quit)
win.show_all()
Gtk.main()