Killing a python thread-CodePudding

I would like to kill somehow a running thread from my GUI application via setting an event, but I can't use a for loop in my thread so I need some other solution to check the event

I have the following situation. In a tkinter gui when I click a button I start a thread and set a global variable.

self.thread = StoppableThread(caller=self)
self.thread.start()
is_running = 1

When I next click the button I check the global variable state and if it is already set I send a stop request:

if is_running:
    is_running = 0
    self.thread.stop()

This is my thread class:

import threading
from time import sleep


class StoppableThread(threading.Thread):
    def __init__(self, caller=None):
        super(StoppableThread, self).__init__()
        self._stop_event = threading.Event()
        self.caller = caller

    def stop(self):
        self._stop_event.set()

    def stopped(self):
        return self._stop_event.is_set()

    def run(self) -> None:
        while True:
            # check for stop
            if self.stopped():
                break

            for i in range(10):
                sleep(1)
                print('Test')

            print('Worker done')
            break

Everything works if I change the while to a for loop, but because in this point in my business logic I doesn't have anything to loop for I need to check somehow different the state of the self.stopped(). Is there any way to check it in the while loop?

Or how can I achive this? I tried to use process instead of thread but it wasnt worked because of an error 'process can't pickle tkinter'.

Thank you for any help

CodePudding user response：

This loop will run forever until you set the flag:

    def run(self):
        while not self.stopped():
            sleep(1)
            print('Test')

You don't actually need an event. A simple Boolean will do.

FOLLOWUP

Here's an example based on your code that shows how this works:

import threading
from time import sleep

class StoppableThread(threading.Thread):
    def __init__(self, caller=None):
        super(StoppableThread, self).__init__()
        self._stop_event = False
        self.caller = caller

    def stop(self):
        self._stop_event = True

    def stopped(self):
        return self._stop_event

    def run(self) -> None:
        while not self.stopped():
            sleep(1)
            print('Test')
        print("exited")

thread = StoppableThread(caller=None)
thread.start()
sleep(5)
thread.stop()
sleep(1)
print("program ending")