在进程中使用标题栏移动Python GTK3窗口

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

class MyWindow(Gtk.Window):
    def __init__(self):
        Gtk.Window.__init__(self, title="移动窗口示例")
        self.set_default_size(400, 300)
        self.set_position(Gtk.WindowPosition.CENTER)
        self.draggable = True

    def on_button_press_event(self, widget, event):
        if event.button == 1 and self.draggable:
            self.drag_start_x = event.x
            self.drag_start_y = event.y

    def on_button_release_event(self, widget, event):
        if event.button == 1 and self.draggable:
            self.drag_start_x = None
            self.drag_start_y = None

    def on_motion_notify_event(self, widget, event):
        if self.draggable and self.drag_start_x is not None and self.drag_start_y is not None:
            self.move(self.get_position()[0] + event.x - self.drag_start_x,
                      self.get_position()[1] + event.y - self.drag_start_y)

    def connect_signals(self):
        self.connect("destroy", Gtk.main_quit)
        self.connect("button-press-event", self.on_button_press_event)
        self.connect("button-release-event", self.on_button_release_event)
        self.connect("motion-notify-event", self.on_motion_notify_event)

    def show_window(self):
        self.connect_signals()
        self.show_all()

if __name__ == "__main__":
    win = MyWindow()
    Gtk.main()