QThread - Error - QThread: Destroyed while thread is still running

Pratik Tayshete

Hi,
I am new to PySide2. I am just trying to launch a sample application and start a thread as the application starts and want to stop the thread as the application closes. When I am closing the application I am getting the following error:
QThread: Destroyed while the thread is still running.
The sample_ui.py is a python file that I converted from sample_ui.ui

Code:

import time
import sys
import sample_ui
from PySide2 import QtWidgets
from PySide2 import QtCore


class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        main_window_ui = sample_ui.Ui_MainWindow()
        main_window_ui.setupUi(self)
        self.custom_thread = CustomThread()
        self.custom_thread.start()

    def closeEvent(self, event):
        self.custom_thread.stop()
        QtWidgets.QMainWindow.closeEvent(self, event)

class CustomThread(QtCore.QThread):
    def __init__(self):
        super(CustomThread, self).__init__()
    def run(self):
        while self.isRunning():
           print("Thread is Running")
           time.sleep(1)
    def stop(self):
        print("Thread Stopped")
        self.quit()




if __name__ == '__main__':
    app = QtWidgets.QApplication()
    main_window = MainWindow()
    main_window.show()
    sys.exit(app.exec_())


**Output:**
Thread is Running
Thread is Running
Thread is Running
Thread Stopped
QThread: Destroyed while thread is still running

Christian Ehrlicher

You have to wait until the thread is really finished, see the documentation