In pyqt5 when i try to close a tread for a my program Ui freezes and stop responding.I'm new to pyqt5 couldn't find a answer for this.
These are the methods in main window(GUI) file
def clickButton_on(self):
print("clicked on/off")
ControlPanel.start()
def clickButton_Off(self):
print("clicked on/off")
ControlPanel.stop()
This is the controlPanel class methods
#classmethod
def start(cls):
print('start method fired')
cls.th = threading.Thread(target=cls.test,args=(cls.attr,))
cls.th.start()
#classmethod
def stop(cls):
print('stop method fired')
cls.th.join()
Full code to recreate the issue
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.uic import loadUi
import sys
import threading
class MainWindow(QtWidgets.QMainWindow):
def __init__(self):
super(MainWindow,self).__init__()
self.b1 = QtWidgets.QPushButton(self)
self.b1.setText("on")
self.b2 = QtWidgets.QPushButton(self)
self.b2.setText("off")
self.b2.move(50,50)
self.b1.clicked.connect(self.clickButton_on)
self.b2.clicked.connect(self.clickButton_Off)
def clickButton_on(self):
print("clicked on/off")
ControlPanel.start()
def clickButton_Off(self):
print("clicked on/off")
ControlPanel.stop()
class ControlPanel:
n=2
#classmethod
def start(cls):
print('start method fired')
cls.th = threading.Thread(target=cls.test,args=(cls.n,))
cls.th.start()
#classmethod
def stop(cls):
print('stop method fired')
cls.th.join()
#classmethod
def test(cls,n):
print('test method fired')
n= 0
while True:
n += 0.1
print(f'thread running n = {n}')
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
window = MainWindow()
window.show()
app.exec_()
windows completely freezes. It doesnt close the thread with .join() it thread keeps running.
Related
My app is freezing because i need to create a new QThread, but am a little confused how to create it when i call widgets that exists on the main class.
here is my code so far ...
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.uic import loadUi
import time
##Main Class
class HWindow(QtWidgets.QWidget):
def __init__(self):
super(HWindow, self).__init__()
loadUi("Hw.ui",self) ##load ui
#Create a QThread object
self.thread = QtCore.QThread()
#Create a QThread object
self.workerMain = WorkerMain()
#Move worker to the thread
self.workerMain.moveToThread(self.thread)
#Start the thread
self.thread.start()
self.runningMain = False
def activateMain(self):
if self.chkb_main.isChecked():
self.lbl_disena_main.setText("Activated")
self.lbl_disena_main.setStyleSheet('color: green;')
#Change variable and call the function
runningMain = True
self.myFunction()
else:
self.lbl_disena_main.setText("Disabled")
self.lbl_disena_main.setStyleSheet('color: red;')
#Change variable and call the function
runningMain = False
def myFunction(self):
while self.runningMain == True:
if self.gpb_main.isChecked() and self.chkb_main.isChecked():
print("running ...")
time.sleep(3)
##Worker Class
class WorkerMain(QtCore.QObject):
threadRunning = QtCore.pyqtSignal()
def __init__(self):
super(WorkerMain, self).__init__()
def run(self):
print("Thread Running ...")
#i cant call my widgets from my main class from here.
'''
while self.runningMain == True:
if self.gpb_main.isChecked() and self.chkb_main.isChecked():
print("running ...")
time.sleep(3)
'''
def stop(self):
print("Thread Stopped ...")
self.terminate()
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
hWindow = QtWidgets.QWidget()
hWindow = HWindow()
hWindow.show()
sys.exit(app.exec_())
Based on pyqt5 documentation and examples, you create a loop on the run method, but it is complicated when i have to create that loop based on what the user select (GUI widgets).
i just figure it out, here is my code ...
class HWindow(QtWidgets.QWidget):
def __init__(self):
super(HWindow, self).__init__()
loadUi("Hw.ui",self) ##load ui
#Create a QThread object
self.thread = QtCore.QThread()
#Create a QThread object
self.workerMain = WorkerMain(self)
#Move worker to the thread
self.workerMain.moveToThread(self.thread)
#Connect the start signal to the run slot
self.workerMain.threadRunning.connect(self.workerMain.run)
#Connect the activateMain signal to the start slot
self.chkb_main.toggled.connect(self.activateMain)
#Start the thread
self.thread.start()
def activateMain(self):
if self.chkb_main.isChecked():
self.lbl_disena_main.setText("Activated")
self.lbl_disena_main.setStyleSheet('color: green;')
self.workerMain.runningMain = True
self.workerMain.threadRunning.emit()
if not self.thread.isRunning():
self.thread.start()
else:
self.lbl_disena_main.setText("Disabled")
self.lbl_disena_main.setStyleSheet('color: red;')
self.workerMain.runningMain = False
self.workerMain.stop()
##Worker Class
class WorkerMain(QtCore.QObject):
threadRunning = QtCore.pyqtSignal()
def __init__(self, parent):
super(WorkerMain, self).__init__()
self.parent = parent
self.runningMain = False
def run(self):
print("Thread Running ...")
while self.runningMain:
if self.parent.gpb_main.isChecked() and self.parent.chkb_main.isChecked():
print("running ...")
time.sleep(3)
def stop(self):
print("Thread Stopped ...")
if self.parent.thread.isRunning():
self.parent.thread.quit()
self.parent.thread.wait()
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
hWindow = QtWidgets.QWidget()
hWindow = HWindow()
hWindow.show()
sys.exit(app.exec_())
I've tried several methods to stop a Qthread, but none seem to work. When I look at the Call Stack, the thread has not ended, and while click again, another thread starts, thus getting infinite active threads and consuming more unnecessary memory. I tried to put terminate() and quit() and nothing stops the thread. So I also tried all of them together and no result
from PyQt5.QtWidgets import QMainWindow, QApplication
from PyQt5.QtCore import QThread
from PyQt5 import QtWidgets
from PyQt5 import QtCore
import time
import sys
class MyThread(QThread):
def run(self):
x=0
print("Starting...")
while x<5:
time.sleep(1.5)
print("Running...")
x=x+1
def close(self):
self.isRunning=False
self.terminate()
self.wait()
self.quit()
self.wait()
print("Done")
class Ui_MainWindow(QMainWindow):
def __init__(self):
super(Ui_MainWindow, self).__init__()
self.btn = QtWidgets.QPushButton(self)
self.btn.setGeometry(QtCore.QRect(77, 30, 50, 30))
self.btn.setText("CLICK")
self.btn.clicked.connect(self.doSomething)
def doSomething(self,event):
self.worker=MyThread()
self.worker.setTerminationEnabled(True)
self.worker.finished.connect(self.worker.close)
self.worker.start()
if __name__ == "__main__":
app = QApplication([])
ui = Ui_MainWindow()
ui.show()
sys.exit(app.exec_())
I managed to solve my problem using threading native library and with pyqtSignal. When clicking on the button, it loses its connection and starts the thread. After the end of the loop in the thread, a signal is issued and thus returning the connection to the button. This way, it prevents the user from clicking the button several times.
from PyQt5.QtWidgets import QMainWindow, QApplication
from PyQt5.QtCore import pyqtSignal
from PyQt5 import QtWidgets
from PyQt5 import QtCore
import time
import sys
import threading
class Ui_MainWindow(QMainWindow):
signal=pyqtSignal(str)
def __init__(self):
super(Ui_MainWindow, self).__init__()
self.btn = QtWidgets.QPushButton(self)
self.btn.setGeometry(QtCore.QRect(77, 30, 50, 30))
self.btn.setText("CLICK")
self.signal.connect(self.signalResponse)
self.btn.clicked.connect(self.doSomething)
def doSomething(self,event):
print("Starting...")
self.btn.disconnect()
worker=threading.Thread(target=self.worker)
worker.start()
def signalResponse(self,response):
if response=="Finished":
self.btn.clicked.connect(self.doSomething)
print(response)
def worker(self):
x=0
while x<5:
time.sleep(0.5)
print("Running...")
x=x+1
self.signal.emit("Finished")
if __name__ == "__main__":
app = QApplication([])
ui = Ui_MainWindow()
ui.show()
sys.exit(app.exec_())
I use a pyqt_signal to transmit a sub window, which has a button whose function is to print. I use a thread to transmit this sub window to the main window to show, however the button loses its function. I know that I should put the statement self.sub_window = SubWindow() into the __init__ function in the second class, but how can I achieve the same effect if I still put this statement here.
# -*- coding: utf-8 -*-
from threading import currentThread
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton
import sys
from PyQt5.QtCore import pyqtSignal, QObject, QThread
class SubWindow(QWidget):
def __init__(self):
super(SubWindow, self).__init__()
self.resize(400, 400)
self.button = QPushButton(self)
self.button.setText('push me to print ***')
self.button.move(200, 200)
self.button.clicked.connect(self.print_)
def print_(self):
print('***')
class SignalStore(QThread):
window_signal = pyqtSignal(object)
def __init__(self):
super(SignalStore, self).__init__()
def run(self):
# if i put this statement here, how can i acquire window's print button function
self.sub_window = SubWindow()
self.window_signal.emit(self.sub_window)
class MainWindow(QWidget):
def __init__(self):
super(MainWindow, self).__init__()
self.resize(400, 400)
self.button = QPushButton(self)
self.button.setText('push me to get subwindow')
self.button.move(200, 200)
self.button.clicked.connect(self.send_signal)
self.med_signal = SignalStore()
self.med_signal.window_signal.connect(self.get_sub_window)
def send_signal(self):
self.med_signal.start()
def get_sub_window(self, para):
self.sub_window = para
self.sub_window.show()
if __name__ == '__main__':
app = QApplication(sys.argv)
win = MainWindow()
win.show()
sys.exit(app.exec_())
Don't create or access gui objects inside threads. Read Qt guide.
GUI Thread and Worker Thread
As mentioned, each program has one thread when it is started. This thread is called the "main thread" (also known as the "GUI thread" in Qt applications). The Qt GUI must run in this thread. All widgets and several related classes, for example QPixmap, don't work in secondary threads. A secondary thread is commonly referred to as a "worker thread" because it is used to offload processing work from the main thread.
This is probably what you are looking for:
import time
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton
import sys
from PyQt5.QtCore import pyqtSignal, QThread, pyqtSlot
class SubWindow(QWidget):
def __init__(self, parent=None):
super(SubWindow, self).__init__(parent)
self.resize(400, 400)
self.button = QPushButton(self)
self.button.setText('push me to print ***')
self.button.move(200, 200)
self.button.clicked.connect(self.print_)
#pyqtSlot()
def print_(self):
print('hello from subwindow')
class SignalStore(QThread):
print_func = pyqtSignal(str)
def __init__(self):
super(SignalStore, self).__init__()
def run(self):
time.sleep(1) # fake working...
self.print_func.emit("hello from thread")
class MainWindow(QWidget):
def __init__(self):
super(MainWindow, self).__init__()
self.resize(400, 400)
self.subwin = SubWindow()
self.button = QPushButton(self)
self.button.setText('push me to get subwindow')
self.button.move(200, 200)
self.button.clicked.connect(self.send_signal)
self.med_signal = SignalStore()
self.med_signal.print_func.connect(self.print_from_main)
def send_signal(self):
self.subwin.show()
self.med_signal.start()
#pyqtSlot(str)
def print_from_main(self, string: str):
print(string)
self.subwin.print_()
if __name__ == '__main__':
app = QApplication(sys.argv)
win = MainWindow()
win.show()
sys.exit(app.exec_())
I want to use startup function which should have while loop.
but I run the code my gui doesn't appear until while loop ends.
I tried with self.show() it can make show gui but it doesn't allow to use sys.exit()
import sys
from PyQt5.QtWidgets import QApplication
from PyQt5 import uic
import time
form_class,QMainWindow=uic.loadUiType('youhua.ui')
class MyWindow(QMainWindow,form_class):
def __init__(self):
super().__init__()
self.setupUi(self)
#self.show()
self.myfunc()
def myfunc(self):
k=1
stat=True
while stat:
k=k+1
time.sleep(1)
self.statusMessage.append(str(k))
QApplication.processEvents()
if k>10:
stat=False
#sys.exit()
if __name__=='__main__':
app=QApplication(sys.argv)
myWindow=MyWindow()
myWindow.show()
app.exec_()
If you need to perform an action again, you have several options.
For example, if each iteration takes very little time, without the possibility of blocking the main loop, you can replace the cycle with a timer (QTimer) and call the method each time, which is responsible for obtaining new data and updating the necessary interface elements in accordance with them:
import sys
from PyQt5 import QtCore, QtWidgets
from PyQt5.QtWidgets import QApplication, QMainWindow
from PyQt5 import uic
from PyQt5.QtCore import QThread, QTimer
import time
#form_class, QMainWindow = uic.loadUiType('youhua.ui')
class MyWindow(QMainWindow): #, form_class):
def __init__(self):
super().__init__()
self.k = 0
centralWidget = QtWidgets.QWidget(self)
self.setCentralWidget(centralWidget)
self.button = QtWidgets.QPushButton('Start', self)
self.button.clicked.connect(self.read_data)
self.label_data = QtWidgets.QLabel(self, alignment=QtCore.Qt.AlignCenter)
self.label_data.setText('Pending')
layout = QtWidgets.QGridLayout(centralWidget)
layout.addWidget(self.label_data)
layout.addWidget(self.button)
self.timer = QtCore.QTimer(self)
self.timer.setInterval(1000)
self.timer.timeout.connect(self.read_data_from_sensor)
#QtCore.pyqtSlot()
def read_data(self):
''' Start / Stop reading at the touch of a button '''
if not self.timer.isActive():
self.timer.start()
self.button.setText("Stop")
else:
self.timer.stop()
self.button.setText("Start")
self.label_data.setText("Pending")
#QtCore.pyqtSlot()
def read_data_from_sensor(self):
dt = time.strftime("%Y-%m-%d %H:%M:%S")
self.label_data.setText(dt)
self.label_data.adjustSize()
self.k += 1
self.statusBar().showMessage('{} item(s)'.format(self.k))
if self.k > 10:
self.timer.stop()
self.button.setText("Start")
self.label_data.setText("Pending")
self.k = 0
if __name__=='__main__':
app = QApplication(sys.argv)
myWindow = MyWindow()
myWindow.show()
app.exec_()
What you wrote may also work, but this is not very good. You can compare.
import sys
from PyQt5.QtWidgets import QApplication, QMainWindow
from PyQt5 import uic
from PyQt5.QtCore import QThread
#import time
#form_class, QMainWindow = uic.loadUiType('youhua.ui')
class MyWindow(QMainWindow): #, form_class):
def __init__(self):
super().__init__()
# self.setupUi(self)
self.show()
self.myfunc()
def myfunc(self):
k = 0
stat = True
while stat:
k += 1
# time.sleep(1)
# self.statusMessage.append(str(k))
self.statusBar().showMessage('{} item(s)'.format(k))
QThread.msleep(1000)
QApplication.processEvents()
if k>10:
stat=False
#sys.exit()
if __name__=='__main__':
app = QApplication(sys.argv)
myWindow = MyWindow()
# myWindow.show()
app.exec_()
In your loop you are sleeping for 10 second, since you are creating a while loop on the main thread, the GUI wont show until the loop is done because it would be blocking the main thread. You can test this by removing time.sleep(1).
Without changing your code much, try this:
import sys,threading, time
from PyQt5.QtWidgets import QApplication
from PyQt5 import uic
form_class,QMainWindow=uic.loadUiType('youhua.ui')
class MyWindow(QMainWindow,form_class):
def __init__(self):
super().__init__()
self.setupUi(self)
#self.show()
t = threading.Thread(target=self.myfunc)
t.start()
def myfunc(self):
k=1
stat=True
while stat:
k=k+1
time.sleep(1)
self.statusMessage.append(str(k))
QApplication.processEvents()
if k>10:
stat=False
#sys.exit() - if you are trying to close the window here use self.close()
if __name__=='__main__':
app=QApplication(sys.argv)
myWindow=MyWindow()
myWindow.show()
sys.exit(app.exec_())
I am new to both pyqt and python so I'm sure that my question would seem stupid, so thank you for reading and answer it. It is really helpful.
Here is my source code
# -*- coding: utf-8 -*-
from PyQt4.QtGui import *
from PyQt4.QtCore import *
import sys
QTextCodec.setCodecForTr(QTextCodec.codecForName("utf8"))
class Prog(QDialog):
def __init__(self,parent=None):
super(Prog,self).__init__(parent)
self.start_P()
def start_P(self):
progressDialog=QProgressDialog(self)
progressDialog.setWindowModality(Qt.WindowModal)
progressDialog.setMinimumDuration(5)
progressDialog.setWindowTitle(self.tr("请等待"))
progressDialog.setLabelText(self.tr("拷贝..."))
progressDialog.setCancelButtonText(self.tr("取消"))
progressDialog.setRange(0,100)
progressDialog.setAutoClose(True)
for i in range(101):
progressDialog.setValue(i)
QThread.msleep(10)
if progressDialog.wasCanceled():
return
self.connect(progressDialog,SIGNAL("closed()"))
def main():
app = QApplication(sys.argv)
pp = Prog()
pp.show()
app.exec_()
if __name__ == '__main__':
main()
There are some Chinese characters, but it's irrelevant. The strange part is when I execute this program I would get a window of progress dialog, that is what I want. But when it is auto closed a pythonw window generated automatically.
I was curious about why this pythonw window was generated and want to know how to avoid it.
That's because you are creating your QProgressDialog as child of a QDialog, checkout the line that says progressDialog=QProgressDialog(self). Checkout how this example works:
#!/usr/bin/env python
#-*- coding:utf-8 -*-
#---------
# IMPORT
#---------
from PyQt4 import QtGui, QtCore
#---------
# MAIN
#---------
class MyThread(QtCore.QThread):
progress = QtCore.pyqtSignal(int)
_stopped = False
def __init__(self, parent=None):
super(MyThread, self).__init__(parent)
def stop(self):
self._stopped = True
def start(self):
self._stopped = False
super(MyThread, self).start()
def run(self):
for progressNumber in range(101):
self.progress.emit(progressNumber)
self.msleep(22)
if self._stopped:
return
class MyWindow(QtGui.QProgressDialog):
def __init__(self, parent=None):
super(MyWindow, self).__init__(parent)
self.threadProgress = MyThread(self)
self.threadProgress.progress.connect(self.setValue)
def stop(self):
self.threadProgress.stop()
def start(self):
self.threadProgress.start()
def hideEvent(self, event):
self.close()
if __name__ == "__main__":
import sys
codec = QtCore.QTextCodec.codecForName("utf8")
QtCore.QTextCodec.setCodecForTr(codec)
app = QtGui.QApplication(sys.argv)
app.setApplicationName('MyWindow')
main = MyWindow()
main.setWindowTitle(main.tr("请等待"))
main.setLabelText(main.tr("拷贝..."))
main.setCancelButtonText(main.tr("取消"))
main.setRange(0,100)
main.canceled.connect(main.stop)
main.show()
main.start()
sys.exit(app.exec_())