4

我想在使用 python xlib 发生更改焦点事件时检测应用程序窗口名称，所以在第一步中我使用以下代码：

#!/usr/bin/env python
#-*- coding:utf-8 -*-
import Xlib.display
import time


display = Xlib.display.Display()
while True:
    window = display.get_input_focus().focus
    wmname = window.get_wm_name()
    wmclass = window.get_wm_class()
    if wmclass is None and wmname is None:
        window = window.query_tree().parent
        wmname = window.get_wm_name()
    print "WM Name: %s" % ( wmname, )
    time.sleep(3)

但是我想要一个正确的方法，然后我研究xlib事件并找到输入焦点事件并编写以下代码：

#!/usr/bin/env python
#-*- coding:utf-8 -*-
import Xlib.display
from Xlib import X

def main():
    display = Xlib.display.Display(':0')
    root = display.screen().root
    root.change_attributes(event_mask=Xlib.X.FocusChangeMask)

    while True:
        event = root.display.next_event()
        #if event.type == X.FocusIn or event.type == X.FocusOut:
        if event.type == X.FocusOut :
            window = display.get_input_focus().focus
            wmname = window.get_wm_name()
            wmclass = window.get_wm_class()
            if wmclass is None and wmname is None:
                window = window.query_tree().parent
                wmname = window.get_wm_name()
            print "WM Name: %s" % ( wmname, )

if __name__ == "__main__":
    main()

可悲的是，它无法正常工作，尤其是在 google chrome 和 firefox 上的选项卡式浏览中，那么对于这种情况有正确的方法吗？

4

2 回答 2

7

您的代码几乎是正确的，但它遗漏了两件事：

  • 而不是只监听焦点更改，它还应该监听包括属性更改的窗口属性事件，WM_NAME当您在浏览器中循环选项卡时也会发生这种情况。
  • 而不是只在根窗口中监听，它应该监听每个窗口（获得焦点）。您可以像使用根窗口一样附加事件处理程序。

话虽如此，这是一个工作示例：

#!/usr/bin/python3
import Xlib
import Xlib.display

disp = Xlib.display.Display()
root = disp.screen().root

NET_WM_NAME = disp.intern_atom('_NET_WM_NAME')
NET_ACTIVE_WINDOW = disp.intern_atom('_NET_ACTIVE_WINDOW')

root.change_attributes(event_mask=Xlib.X.FocusChangeMask)
while True:
    try:
        window_id = root.get_full_property(NET_ACTIVE_WINDOW, Xlib.X.AnyPropertyType).value[0]
        window = disp.create_resource_object('window', window_id)
        window.change_attributes(event_mask=Xlib.X.PropertyChangeMask)
        window_name = window.get_full_property(NET_WM_NAME, 0).value
    except Xlib.error.XError: #simplify dealing with BadWindow
        window_name = None
    print(window_name)
    event = disp.next_event()
于 2015-07-09T19:20:45.717 回答
2

@rr- 正如我刚刚在别处更正的那样，您需要同时查询当前_NET_WM_NAME（UTF-8）和旧版WM_NAME（非 UTF8）属性，否则默认的 xterm 配置将不返回任何标题。

我刚刚在您的 Unix 和 Linux StackExchange 问题上发布了一个完整的工作示例。

为了避免让人们进行交叉引用搜索，这是我在那里发布的代码的副本：

#!/usr/bin/python
from contextlib import contextmanager
import Xlib
import Xlib.display

disp = Xlib.display.Display()
root = disp.screen().root

NET_ACTIVE_WINDOW = disp.intern_atom('_NET_ACTIVE_WINDOW')
NET_WM_NAME = disp.intern_atom('_NET_WM_NAME')  # UTF-8
WM_NAME = disp.intern_atom('WM_NAME')           # Legacy encoding

last_seen = { 'xid': None, 'title': None }

@contextmanager
def window_obj(win_id):
    """Simplify dealing with BadWindow (make it either valid or None)"""
    window_obj = None
    if win_id:
        try:
            window_obj = disp.create_resource_object('window', win_id)
        except Xlib.error.XError:
            pass
    yield window_obj

def get_active_window():
    win_id = root.get_full_property(NET_ACTIVE_WINDOW,
                                       Xlib.X.AnyPropertyType).value[0]

    focus_changed = (win_id != last_seen['xid'])
    if focus_changed:
        with window_obj(last_seen['xid']) as old_win:
            if old_win:
                old_win.change_attributes(event_mask=Xlib.X.NoEventMask)

        last_seen['xid'] = win_id
        with window_obj(win_id) as new_win:
            if new_win:
                new_win.change_attributes(event_mask=Xlib.X.PropertyChangeMask)

    return win_id, focus_changed

def _get_window_name_inner(win_obj):
    """Simplify dealing with _NET_WM_NAME (UTF-8) vs. WM_NAME (legacy)"""
    for atom in (NET_WM_NAME, WM_NAME):
        try:
            window_name = win_obj.get_full_property(atom, 0)
        except UnicodeDecodeError:  # Apparently a Debian distro package bug
            title = "<could not decode characters>"
        else:
            if window_name:
                win_name = window_name.value
                if isinstance(win_name, bytes):
                    # Apparently COMPOUND_TEXT is so arcane that this is how
                    # tools like xprop deal with receiving it these days
                    win_name = win_name.decode('latin1', 'replace')
                return win_name
            else:
                title = "<unnamed window>"

    return "{} (XID: {})".format(title, win_obj.id)

def get_window_name(win_id):
    if not win_id:
        last_seen['title'] = "<no window id>"
        return last_seen['title']

    title_changed = False
    with window_obj(win_id) as wobj:
        if wobj:
            win_title = _get_window_name_inner(wobj)
            title_changed = (win_title != last_seen['title'])
            last_seen['title'] = win_title

    return last_seen['title'], title_changed

def handle_xevent(event):
    if event.type != Xlib.X.PropertyNotify:
        return

    changed = False
    if event.atom == NET_ACTIVE_WINDOW:
        if get_active_window()[1]:
            changed = changed or get_window_name(last_seen['xid'])[1]
    elif event.atom in (NET_WM_NAME, WM_NAME):
        changed = changed or get_window_name(last_seen['xid'])[1]

    if changed:
        handle_change(last_seen)

def handle_change(new_state):
    """Replace this with whatever you want to actually do"""
    print(new_state)

if __name__ == '__main__':
    root.change_attributes(event_mask=Xlib.X.PropertyChangeMask)

    get_window_name(get_active_window()[0])
    handle_change(last_seen)

    while True:  # next_event() sleeps until we get an event
        handle_xevent(disp.next_event())

此 GitHub Gist中还有一个评论较多的版本。

于 2017-01-05T18:00:28.397 回答