screen_monitor.py

#!/usr/bin/env python3
import subprocess
import time

# --- set both commands (connect / disconnect) below
connect_command = "bash ~/.screenlayout/office_docked.sh"
disconnect_command = "bash ~/.screenlayout/laptop.sh"
# ---


# Wait for xrandr to startup before executing the changes.
while True:
    time.sleep(5)
    try:
        subprocess.Popen(["xrandr"])
    except:
        pass
    else:
        break


def get(cmd):
    return subprocess.check_output(cmd).decode("utf-8")


# - to count the occurrenc of " connected "
def count_screens(xr):
    return xr.count(" connected ")


# - to run the connect / disconnect command(s)
def run_command(cmd):
    subprocess.Popen(["/bin/bash", "-c", cmd])


# first count
xr1 = None


while True:
    time.sleep(5)
    # second count
    xr2 = count_screens(get(["xrandr"]))
    # check if there is a change in the screen state
    if xr2 != xr1:
        if xr2 == 2:

            # command to run if connected (two screens)
            run_command(connect_command)
        elif xr2 == 1:
            # command to run if disconnected (one screen)
            # uncomment run_command(disconnect_command) to enable,
            # then also comment out pass
            # pass
            run_command(disconnect_command)
    # set the second count as initial state for the next loop
    xr1 = xr2