python wnck 在 pdb.set_trace() 之后才返回任何数据

Question

在 Ubuntu Linux / Gnome 上，我尝试使用 python 的 wnck 绑定来获取所有打开的窗口的列表。

我的代码如下所示：

#! /usr/bin/python

from pprint import pprint
import wnck

screen = wnck.screen_get_default()

pprint(screen.get_windows())

import pdb ; pdb.set_trace()

pprint(screen.get_windows())

输出如下：

** (windowlist.py:4501): WARNING **: Trying to register gtype 'WnckWindowState' as enum when in fact it is of type 'GFlags'

** (windowlist.py:4501): WARNING **: Trying to register gtype 'WnckWindowActions' as enum when in fact it is of type 'GFlags'

** (windowlist.py:4501): WARNING **: Trying to register gtype 'WnckWindowMoveResizeMask' as enum when in fact it is of type 'GFlags'
[]
> /home/rory/personal/diriu/windowlist.py(12)<module>()
-> pprint(screen.get_windows())
(Pdb) c
[<wnck.Window object at 0xb61db0cc (WnckWindow at 0x992c000)>,
 <wnck.Window object at 0xb61db0f4 (WnckWindow at 0x992c0a8)>,
 <wnck.Window object at 0xb61db11c (WnckWindow at 0x992c150)>,
 <wnck.Window object at 0xb61db144 (WnckWindow at 0x992c1f8)>,
 <wnck.Window object at 0xb61db16c (WnckWindow at 0x992c2a0)>,
 <wnck.Window object at 0xb61db194 (WnckWindow at 0x992c348)>,
 <wnck.Window object at 0xb61db1bc (WnckWindow at 0x992c3f0)>,
 <wnck.Window object at 0xb61db1e4 (WnckWindow at 0x992c498)>,
 <wnck.Window object at 0xb61db20c (WnckWindow at 0x992c540)>,
 <wnck.Window object at 0xb61db234 (WnckWindow at 0x992c5e8)>,
 <wnck.Window object at 0xb61db25c (WnckWindow at 0x992c690)>,
 <wnck.Window object at 0xb61db284 (WnckWindow at 0x992c738)>]

第一个 get_windows() 调用返回 []，一个空列表。第二个 get_windows() 调用返回打开的窗口列表。在 pdb 中，我只按 c 继续而不执行任何操作（在 pdb 中）。

如果我注释掉 pdb，则两个 get_windows() 调用都会返回 []。如果我在 pdb 之前多次重复 get_windows() 调用，则什么也没有。如果我在 pdb 之后多次重复 get_windows() 调用，我会不断获得完整列表。

为什么此调用仅在空 pdb 之后才有效？在没有 pdb 的情况下如何使其工作？

Answer 1

文件 so-wnck.py （来自 我如何抓取标题中含有特定单词的所有窗口？）

import pygtk
pygtk.require('2.0')
import gtk
import wnck

screen = wnck.screen_get_default()
while gtk.events_pending():
    gtk.main_iteration()

windows = screen.get_windows()
print (windows)

python so-wnck.py

** (so-wnck.py:2367): WARNING **: Trying to register gtype 'WnckWindowState' as enum when in fact it is of type 'GFlags'

** (so-wnck.py:2367): WARNING **: Trying to register gtype 'WnckWindowActions' as enum when in fact it is of type 'GFlags'

** (so-wnck.py:2367): WARNING **: Trying to register gtype 'WnckWindowMoveResizeMask' as enum when in fact it is of type 'GFlags'
[<wnck.Window object at 0xb7566694 (WnckWindow at 0x97c51f8)>,
 <wnck.Window object at 0xb75666bc (WnckWindow at 0x97c52a0)>, 
 <wnck.Window object at 0xb75666e4 (WnckWindow at 0x97c5348)>, 
 <wnck.Window object at 0xb756670c (WnckWindow at 0x97c53f0)>, 
 <wnck.Window object at 0xb7566734 (WnckWindow at 0x97c5498)>,
 <wnck.Window object at 0xb756675c (WnckWindow at 0x97c5540)>, 
 <wnck.Window object at 0xb7566784 (WnckWindow at 0x97c55e8)>]

Answer 2

我不使用 wnck，但我认为如果 pdb 两次调用 get_window 之间的时间足以初始化窗口列表。在调用 get_window 之前尝试使用睡眠并延迟一些。