Does the xlib event have an active window event?

Question

I am trying to write a program that keeps track of when the active window is being modified using Xlib. It’s hard for me to figure out how to do this. These are my ideas so far:

• Every second uses _NET_ACTIVE_WINDOW to get the active window, and if it has been changed, then the corresponding code for the event is executed.
• Get a list of all windows and listen to their focus in the event. I would have to figure out how to keep an updated list of open windows, though.

Is it their easier / better? I am new to programming with Xlib.

Answer 1

Can't you just select PropertyChange in the root window to receive PropertyNotify events dispatched when any property is updated, and then check each event to see if it was for _NET_ACTIVE_WINDOW ?

Answer 2

Here's a Python implementation of what @alanc has proposed.

 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') last_seen = {'xid': None} def get_active_window(): window_id = root.get_full_property(NET_ACTIVE_WINDOW, Xlib.X.AnyPropertyType).value[0] focus_changed = (window_id != last_seen['xid']) last_seen['xid'] = window_id return window_id, focus_changed def get_window_name(window_id): try: window_obj = disp.create_resource_object('window', window_id) window_name = window_obj.get_full_property(NET_WM_NAME, 0).value except Xlib.error.XError: window_name = None return window_name if __name__ == '__main__': root.change_attributes(event_mask=Xlib.X.PropertyChangeMask) while True: win, changed = get_active_window() if changed: print(get_window_name(win)) while True: event = disp.next_event() if (event.type == Xlib.X.PropertyNotify and event.atom == NET_ACTIVE_WINDOW): break 

A more complete version, which I wrote as an example for someone, is in this thread .

Answer 3

I was looking for "active capture of windows events." What I use in average time (and may be useful for you) is a combination of xdotool and xwininfo .

 xwininfo -id "$(xdotool getactivewindow)"