#!/usr/bin/python3
 
import pyatspi
import sys
 
def registerAndStart():
    pyatspi.Registry.registerKeystrokeListener(
        onKey,
        kind=(pyatspi.KEY_PRESSED_EVENT, pyatspi.KEY_RELEASED_EVENT))
    pyatspi.Registry.start()
 
def deregisterAndStop():
    pyatspi.Registry.deregisterKeystrokeListener(
        onKey,
        kind=(pyatspi.KEY_PRESSED_EVENT, pyatspi.KEY_RELEASED_EVENT))
    pyatspi.Registry.stop()
    sys.exit(0)
 
def onKey(e):
    if e.type == pyatspi.KEY_PRESSED_EVENT:
        eType = "PRESSED"
    elif e.type == pyatspi.KEY_RELEASED_EVENT:
        eType = "RELEASED"
    else:
        eType = "UNKNOWN"

    print("%s: '%s'" % (eType, e.event_string))
    if e.event_string == "F4" and eType == "PRESSED":
        deregisterAndStop()
 
print("Press F4 to terminate this listener")
registerAndStart()