Pyqt5 stop QThread worker on QAction - python-3.x

Question

hello I have QTheard worker that start with click at QAction.
....
self.start_update = QAction('&Start', self)
self.start_update.triggered.connect(self._start_thread)
self.stop_update.setVisible(True)
self.stop_update.triggered.connect(self._stop_thread)
self.stop_update.setVisible(False)
...
...
def _start_thread(self):
self.start_update.setVisible(False)
self.stop_update.setVisible(True)
self.myworker.start()
...
...
def _stop_thread(self):
self.myworker.stop() # That close app with error
self.stop_update.setVisible(False)
self.start_update.setVisible(True)
...
Please help how to close terminate Worker correctly. Atm worker have __del__ and run (logic) method. Maybe need to add some method for correct worker closing?

Answer 1

Your application might look like this:
import sys
from PyQt5.QtGui import *
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
class AThread(QThread):
threadSignalAThread = pyqtSignal(int)
def __init__(self):
super().__init__()
def run(self):
count = 0
while count < 1000:
QThread.msleep(200)
count += 1
self.threadSignalAThread.emit(count)
class MsgBoxAThread(QDialog):
def __init__(self):
super().__init__()
layout = QVBoxLayout(self)
self.label = QLabel("")
layout.addWidget(self.label)
close_btn = QPushButton("Close window")
layout.addWidget(close_btn)
close_btn.clicked.connect(self.close)
self.setGeometry(900, 300, 400, 80)
self.setWindowTitle('MsgBox AThread(QThread)')
class Example(QMainWindow):
def __init__(self, parent=None, *args):
super().__init__(parent, *args)
self.setWindowTitle("Pyqt5 stop QThread worker on QAction")
self.setGeometry(550, 300, 300, 300)
centralWidget = QWidget(self)
self.setCentralWidget(centralWidget)
layout = QVBoxLayout(centralWidget)
self.lbl = QLabel("Start")
layout.addWidget(self.lbl)
bar = self.menuBar()
barThread = bar.addMenu('Thread')
quit = bar.addMenu('Quit')
quit.aboutToShow.connect(app.quit)
self.start_update = QAction('&Start', self)
self.start_update.setShortcut('Ctrl+S')
self.start_update.triggered.connect(self._start_thread)
self.stop_update = QAction('Sto&p', self)
self.stop_update.setShortcut('Ctrl+P')
self.stop_update.setVisible(False)
self.stop_update.triggered.connect(self._stop_thread)
barThread.addAction(self.start_update)
barThread.addAction(self.stop_update)
self.msg = MsgBoxAThread()
self.myworker = None
self.counter = 0
self.timer = QTimer()
self.timer.setInterval(1000)
self.timer.timeout.connect(self.recurring_timer)
self.timer.start()
self.show()
def recurring_timer(self):
self.counter += 1
self.lbl.setText(" Do something in the GUI: <b> %d </b>" % self.counter)
def _start_thread(self):
self.start_update.setVisible(False)
self.stop_update.setVisible(True)
self.myworker = AThread()
self.myworker.threadSignalAThread.connect(self.on_threadSignalAThread)
self.myworker.finished.connect(self.finishedAThread)
self.myworker.start()
def finishedAThread(self):
self.myworker = None
self.start_update.setVisible(True)
self.stop_update.setVisible(False)
def on_threadSignalAThread(self, value):
self.msg.label.setText(str(value))
if not self.msg.isVisible():
self.msg.show()
def _stop_thread(self):
self.stop_update.setVisible(False)
self.start_update.setVisible(True)
self.myworker.terminate()
self.myworker = None
def closeEvent(self, event):
reply = QMessageBox.question(self, 'Question',
"Are you sure you want to close the application?",
QMessageBox.Yes,
QMessageBox.No)
if reply == QMessageBox.Yes:
if self.myworker:
self.myworker.quit()
del self.myworker
self.msg.close()
super(Example, self).closeEvent(event)
else:
event.ignore()
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Example()
#ex.show()
sys.exit(app.exec_())