问题
I made one script some time ago to record the monitor frames of the user and now I am trying to create a GUI for it. For now it has only a START and a STOP button, but the STOP button does not stop the recording.
How could I change my stop_thread function for it to work? Should I terminate the worker first and then the thread? How can I terminate the worker anyway?
import sys
from PyQt5.QtWidgets import (QWidget,
QPushButton, QApplication, QGridLayout)
from PyQt5.QtCore import QThread, QObject
class Worker(QObject):
def __init__(self, parent=None):
QObject.__init__(self, parent=parent)
def do_work(self):
i = 1
while True:
print(i)
QThread.sleep(1)
i = i + 1
def stop(self):
print("stopped")
self.deleteLater() # How do I stop it?
class Gui(QWidget):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
# Buttons:
self.btn_start = QPushButton('Start')
self.btn_start.resize(self.btn_start.sizeHint())
self.btn_start.move(50, 50)
self.btn_stop = QPushButton('Stop')
self.btn_stop.resize(self.btn_stop.sizeHint())
self.btn_stop.move(150, 50)
# GUI title, size, etc...
self.setGeometry(300, 300, 300, 220)
self.setWindowTitle('ThreadTest')
self.layout = QGridLayout()
self.layout.addWidget(self.btn_start, 0, 0)
self.layout.addWidget(self.btn_stop, 0, 50)
self.setLayout(self.layout)
# Thread:
self.thread = QThread()
self.worker = Worker()
self.worker.moveToThread(self.thread)
self.thread.started.connect(self.worker.do_work) # when thread starts, start worker
self.thread.finished.connect(self.worker.stop) # when thread finishes, stop worker
# Start Button action:
self.btn_start.clicked.connect(self.thread.start)
# Stop Button action:
self.btn_stop.clicked.connect(self.stop_thread)
self.show()
# When stop_btn is clicked this runs. Terminates the worker and the thread.
def stop_thread(self):
print("It should stop printing numbers now and not crash")
self.worker.disconnect()
self.thread.terminate()
if __name__ == '__main__':
app = QApplication(sys.argv)
gui = Gui()
sys.exit(app.exec_())
EDIT: While MalloyDelacroix answer worked for some time, I've now run into a problem:
If do_work from Worker is an imported function which loops forever, how can I stop it with a button click? I want to force close it.
from test import s_main
class Worker(QObject):
finished = pyqtSignal() # give worker class a finished signal
def __init__(self, parent=None):
QObject.__init__(self, parent=parent)
self.continue_run = True # provide a bool run condition for the class
def do_work(self):
s_main()
self.finished.emit() # emit the finished signal when the loop is done
def stop(self):
self.continue_run = False # set the run condition to false on stop
test.py:
def s_main():
i = 1
while True:
i = i + 1
print(i)
回答1:
Below is a working example of the code you posted. I have made comments in the areas that I changed with the explanations as to why.
import sys
from PyQt5.QtWidgets import (QWidget,
QPushButton, QApplication, QGridLayout)
from PyQt5.QtCore import QThread, QObject, pyqtSignal
class Worker(QObject):
finished = pyqtSignal() # give worker class a finished signal
def __init__(self, parent=None):
QObject.__init__(self, parent=parent)
self.continue_run = True # provide a bool run condition for the class
def do_work(self):
i = 1
while self.continue_run: # give the loop a stoppable condition
print(i)
QThread.sleep(1)
i = i + 1
self.finished.emit() # emit the finished signal when the loop is done
def stop(self):
self.continue_run = False # set the run condition to false on stop
class Gui(QWidget):
stop_signal = pyqtSignal() # make a stop signal to communicate with the worker in another thread
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
# Buttons:
self.btn_start = QPushButton('Start')
self.btn_start.resize(self.btn_start.sizeHint())
self.btn_start.move(50, 50)
self.btn_stop = QPushButton('Stop')
self.btn_stop.resize(self.btn_stop.sizeHint())
self.btn_stop.move(150, 50)
# GUI title, size, etc...
self.setGeometry(300, 300, 300, 220)
self.setWindowTitle('ThreadTest')
self.layout = QGridLayout()
self.layout.addWidget(self.btn_start, 0, 0)
self.layout.addWidget(self.btn_stop, 0, 50)
self.setLayout(self.layout)
# Thread:
self.thread = QThread()
self.worker = Worker()
self.stop_signal.connect(self.worker.stop) # connect stop signal to worker stop method
self.worker.moveToThread(self.thread)
self.worker.finished.connect(self.thread.quit) # connect the workers finished signal to stop thread
self.worker.finished.connect(self.worker.deleteLater) # connect the workers finished signal to clean up worker
self.thread.finished.connect(self.thread.deleteLater) # connect threads finished signal to clean up thread
self.thread.started.connect(self.worker.do_work)
self.thread.finished.connect(self.worker.stop)
# Start Button action:
self.btn_start.clicked.connect(self.thread.start)
# Stop Button action:
self.btn_stop.clicked.connect(self.stop_thread)
self.show()
# When stop_btn is clicked this runs. Terminates the worker and the thread.
def stop_thread(self):
self.stop_signal.emit() # emit the finished signal on stop
if __name__ == '__main__':
app = QApplication(sys.argv)
gui = Gui()
sys.exit(app.exec_())
Edit:
The answer is still basically the same, you just need to connect the stop button to the other methods run condition.
test.py
import time
run = True
def s_main():
x = 1
while run:
print(x)
x += 1
time.sleep(1)
worker.py
import test
class Worker(QObject):
finished = pyqtSignal() # give worker class a finished signal
def __init__(self, parent=None):
QObject.__init__(self, parent=parent)
def do_work(self):
s_main()
self.finished.emit() # emit the finished signal when the loop is done
def stop(self):
test.run = False # set the run condition to false on stop
来源：https://stackoverflow.com/questions/49886313/how-to-run-a-while-loop-with-pyqt5