Python Gtk+3教程23应用程序没有显示什么是预期的？

Question

我正在为桌面应用程序开发一个UI。我已经看到“菜单”被废弃了，因此决定第一次使用Gtk.Application类。

在下面的链接https://python-gtk-3-tutorial.readthedocs.io/en/latest/application.html#example中，它们提供了以下代码：

import sys

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

# This would typically be its own file
MENU_XML="""
<?xml version="1.0" encoding="UTF-8"?>
<interface>
  <menu id="app-menu">
    <section>
      <attribute name="label" translatable="yes">Change label</attribute>
      <item>
        <attribute name="action">win.change_label</attribute>
        <attribute name="target">String 1</attribute>
        <attribute name="label" translatable="yes">String 1</attribute>
      </item>
      <item>
        <attribute name="action">win.change_label</attribute>
        <attribute name="target">String 2</attribute>
        <attribute name="label" translatable="yes">String 2</attribute>
      </item>
      <item>
        <attribute name="action">win.change_label</attribute>
        <attribute name="target">String 3</attribute>
        <attribute name="label" translatable="yes">String 3</attribute>
      </item>
    </section>
    <section>
      <item>
        <attribute name="action">win.maximize</attribute>
        <attribute name="label" translatable="yes">Maximize</attribute>
      </item>
    </section>
    <section>
      <item>
        <attribute name="action">app.about</attribute>
        <attribute name="label" translatable="yes">_About</attribute>
      </item>
      <item>
        <attribute name="action">app.quit</attribute>
        <attribute name="label" translatable="yes">_Quit</attribute>
        <attribute name="accel">&lt;Primary&gt;q</attribute>
    </item>
    </section>
  </menu>
</interface>
"""

class AppWindow(Gtk.ApplicationWindow):

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        # This will be in the windows group and have the "win" prefix
        max_action = Gio.SimpleAction.new_stateful("maximize", None,
                                           GLib.Variant.new_boolean(False))
        max_action.connect("change-state", self.on_maximize_toggle)
        self.add_action(max_action)

        # Keep it in sync with the actual state
        self.connect("notify::is-maximized",
                            lambda obj, pspec: max_action.set_state(
                                               GLib.Variant.new_boolean(obj.props.is_maximized)))

        lbl_variant = GLib.Variant.new_string("String 1")
        lbl_action = Gio.SimpleAction.new_stateful("change_label", lbl_variant.get_type(),
                                               lbl_variant)
        lbl_action.connect("change-state", self.on_change_label_state)
        self.add_action(lbl_action)

        self.label = Gtk.Label(label=lbl_variant.get_string(),
                               margin=30)
        self.add(self.label)
        self.label.show()

    def on_change_label_state(self, action, value):
        action.set_state(value)
        self.label.set_text(value.get_string())

    def on_maximize_toggle(self, action, value):
        action.set_state(value)
        if value.get_boolean():
            self.maximize()
        else:
            self.unmaximize()

class Application(Gtk.Application):

    def __init__(self, *args, **kwargs):
        super().__init__(*args, application_id="org.example.myapp",
                         flags=Gio.ApplicationFlags.HANDLES_COMMAND_LINE,
                         **kwargs)
        self.window = None

        self.add_main_option("test", ord("t"), GLib.OptionFlags.NONE,
                             GLib.OptionArg.NONE, "Command line test", None)

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

        action = Gio.SimpleAction.new("about", None)
        action.connect("activate", self.on_about)
        self.add_action(action)

        action = Gio.SimpleAction.new("quit", None)
        action.connect("activate", self.on_quit)
        self.add_action(action)

        builder = Gtk.Builder.new_from_string(MENU_XML, -1)
        self.set_app_menu(builder.get_object("app-menu"))

    def do_activate(self):
        # We only allow a single window and raise any existing ones
        if not self.window:
            # Windows are associated with the application
            # when the last one is closed the application shuts down
            self.window = AppWindow(application=self, title="Main Window")

        self.window.present()

    def do_command_line(self, command_line):
        options = command_line.get_options_dict()
        # convert GVariantDict -> GVariant -> dict
        options = options.end().unpack()

        if "test" in options:
            # This is printed on the main instance
            print("Test argument recieved: %s" % options["test"])

        self.activate()
        return 0

    def on_about(self, action, param):
        about_dialog = Gtk.AboutDialog(transient_for=self.window, modal=True)
        about_dialog.present()

    def on_quit(self, action, param):
        self.quit()

if __name__ == "__main__":
    app = Application()
    app.run(sys.argv)

其中，它们将下列图像显示为所述输出：

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然而，我正在运行它，并且正在显示这个窗口：

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我只是在抨击"python3 application.py“，我想我想知道我是哑巴还是代码不再是什么样子了。

Answer 1

这肯定是发行版和/或窗口管理器的问题，因为在Linux 19中，我得到了这个窗口：

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