I'm trying to develop a browser that allows downloads but disables all ways for uploading something to the internet. I developed the browser with PyQt5 but I can't figure out how to disable the FileDialog (ex when clicking on add an attachment in Gmail). I already set up settings disabling things like LocalContentCanAccessRemoteUrls and LocalContentCanAccessFileUrls among other flags. I also subclassed the QWebEnginePage and modified the "chooseFile" function without any luck. Below you can see my code, here you can find the UI and resources file.
# Python import
import sys
# PYQT Imports
from PyQt5 import QtCore, QtGui, QtWidgets, QtWebEngineWidgets
# from QtWebEngineWidgets.QWebEngineView import QWebEngineView
# UI IMPORT
import UI_Sailor
class WebPage(QtWebEngineWidgets.QWebEnginePage):
def chooseFile(self, frame=None, path=''):
print ('Called this')
return
class Sailor(QtWidgets.QMainWindow, UI_Sailor.Ui_Sailor):
def __init__(self):
super(self.__class__, self).__init__()
self.setupUi(self)
# self.setWindowIcon(QtGui.QIcon(':/Icons/Icons/Icon_Small.png'))
self.setWindowTitle('Sailor - 1.0.0')
glob_settings = QtWebEngineWidgets.QWebEngineSettings.globalSettings()
self.setWebSettings(glob_settings)
self.create_connections()
def setWebSettings(self, object_settings):
print ('Called')
# Global web settings
object_settings.setAttribute(1, True) # JaveScript
object_settings.setAttribute(3, False) # Clipboard (JaveScript)
object_settings.setAttribute(5, False) # Local Storage
object_settings.setAttribute(6, False) # LocalContentCanAccessRemoteUrls
object_settings.setAttribute(7, False) # XSSAuditingEnabled
object_settings.setAttribute(9, False) # LocalContentCanAccessFileUrls
object_settings.setAttribute(11, True) # ScrollAnimatorEnabled
object_settings.setAttribute(14, True) # FullScreenSupportEnabled
# Check that the options are applied
# print (object_settings.testAttribute(1)) # JaveScript
# print (object_settings.testAttribute(2)) # JaveScript
# print (object_settings.testAttribute(3)) # Clipboard (JaveScript)
# print (object_settings.testAttribute(5)) # Local Storage
# print (object_settings.testAttribute(6)) # LocalContentCanAccessRemoteUrls
# print (object_settings.testAttribute(7)) # XSSAuditingEnabled
# print (object_settings.testAttribute(9)) # LocalContentCanAccessFileUrls
# print (object_settings.testAttribute(11)) # ScrollAnimatorEnabled
# print (object_settings.testAttribute(14)) # FullScreenSupportEnabled
def create_connections(self):
self.TXT_Address.returnPressed.connect(self.web_load_url)
# self.WEB_View.urlChanged.connect(self.debug)
def web_load_url(self):
# Creates the proper url
url_base = str(self.TXT_Address.text())
url_clean = self.url_handler(url_base)
# Loads the url
# self.WEB_View.setUrl(QtCore.QUrl(url_clean))
self.WEB_View.setPage(WebPage(self.WEB_View))
self.WEB_View.load(QtCore.QUrl(url_clean))
self.setWebSettings(self.WEB_View.settings())
def debug(self):
print ('called')
def url_handler(self, url):
if 'http' not in url:
return 'http://{}'.format(url)
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
form = Sailor()
form.show()
app.exec_()
You defined the wrong method in the WebPage class. It looks like you may have used the signature from the QtWebKit.QWebPage class, rather than the one from the QWebEnginePage class. Here is a minimal working example:
import sys
from PyQt5 import QtCore, QtWidgets, QtWebEngineWidgets
class WebPage(QtWebEngineWidgets.QWebEnginePage):
def chooseFiles(self, mode, oldfiles, mimetypes):
print('Called this')
return []
class Window(QtWebEngineWidgets.QWebEngineView):
def __init__(self):
super(Window, self).__init__()
self.setPage(WebPage(self))
self.setHtml('<input type="file">')
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
window = Window()
window.setGeometry(600, 100, 400, 200)
window.show()
sys.exit(app.exec_())
Related
I am trying to convert from pyqt5 to pyqt6 the code in the first answer of this post but so far no luck.
I managed to have something running with the following code:
#!/usr/bin/env python
# -*- coding: utf-8 -*-
from PyQt6.QtWidgets import QApplication
from PyQt6.QtCore import QStringListModel
from PyQt6 import QtCore, QtGui, QtWidgets
from PyQt6.QtCore import Qt, QSortFilterProxyModel
from PyQt6.QtWidgets import QCompleter, QComboBox
import sys
class ExtendedComboBox(QComboBox):
def __init__(self, parent=None):
super(ExtendedComboBox, self).__init__(parent)
self.setFocusPolicy(Qt.FocusPolicy.StrongFocus)
self.setEditable(True)
# add a filter model to filter matching items
self.pFilterModel = QSortFilterProxyModel(self)
self.pFilterModel.setFilterCaseSensitivity(Qt.CaseSensitivity.CaseInsensitive)
self.pFilterModel.setSourceModel(self.model())
# add a completer, which uses the filter model
self.completer = QCompleter(self.pFilterModel, self)
# always show all (filtered) completions
self.completer.setCompletionMode(QCompleter.CompletionMode.UnfilteredPopupCompletion)
self.setCompleter(self.completer)
# connect signals
self.lineEdit().textEdited.connect(self.pFilterModel.setFilterFixedString)
self.completer.activated.connect(self.on_completer_activated)
# on selection of an item from the completer, select the corresponding item from combobox
def on_completer_activated(self, text):
if text:
index = self.findText(text)
self.setCurrentIndex(index)
self.activated[str].emit(self.itemText(index))
# on model change, update the models of the filter and completer as well
def setModel(self, model):
super(ExtendedComboBox, self).setModel(model)
self.pFilterModel.setSourceModel(model)
self.completer.setModel(self.pFilterModel)
# on model column change, update the model column of the filter and completer as well
def setModelColumn(self, column):
self.completer.setCompletionColumn(column)
self.pFilterModel.setFilterKeyColumn(column)
super(ExtendedComboBox, self).setModelColumn(column)
if __name__ == "__main__":
app = QApplication(sys.argv)
string_list = ['hola muchachos', 'adios amigos', 'hello world', 'good bye']
combo = ExtendedComboBox()
# either fill the standard model of the combobox
combo.addItems(string_list)
# or use another model
#combo.setModel(QStringListModel(string_list))
combo.resize(300, 40)
combo.show()
sys.exit(app.exec())
However I encounter a strange bug when I start to type something in the ExtendedComboBox(for instance the letter h) and then I click on one of the filtered entries (for example Hello word) I have the following error:
python test.py
Traceback (most recent call last):
File "test.py", line 38, in on_completer_activated
self.activated[str].emit(self.itemText(index))
KeyError: 'there is no matching overloaded signal'
Aborted (core dumped)
The same does not happen in the original version therefore I think that there is something similar in pyqt6 which I cannot figure out
try this:
class ExtendedComboBox(QComboBox):
#lineEdit = LineEdit()
def __init__(self, parent=None):
super(ExtendedComboBox, self).__init__(parent)
self.setFocusPolicy(Qt.FocusPolicy.StrongFocus)
self.setEditable(True)
# add a filter model to filter matching items
self.pFilterModel = QSortFilterProxyModel(self)
self.pFilterModel.setFilterCaseSensitivity(Qt.CaseSensitivity.CaseInsensitive)
self.pFilterModel.setSourceModel(self.model())
# add a completer, which uses the filter model
self.completer = QCompleter(self.pFilterModel, self)
# always show all (filtered) completions
self.completer.setCompletionMode(QCompleter.CompletionMode.UnfilteredPopupCompletion)
self.setCompleter(self.completer)
# connect signals
self.lineEdit().textEdited.connect(self.pFilterModel.setFilterFixedString)
self.completer.activated.connect(self.on_completer_activated)
def focusInEvent(self, e):
super().lineEdit().focusInEvent(e)
QTimer.singleShot(0, self.lineEdit().selectAll)
# QTimer.singleShot(0, self.showPopup)
# on selection of an item from the completer, select the corresponding item from combobox
def on_completer_activated(self, text):
if text:
index = self.findText(text)
self.setCurrentIndex(index)
# self.activated[str].emit(self.itemText(index))
# on model change, update the models of the filter and completer as well
def setModel(self, model):
super(ExtendedComboBox, self).setModel(model)
self.pFilterModel.setSourceModel(model)
self.completer.setModel(self.pFilterModel)
# on model column change, update the model column of the filter and completer as well
def setModelColumn(self, column):
self.completer.setCompletionColumn(column)
self.pFilterModel.setFilterKeyColumn(column)
super(ExtendedComboBox, self).setModelColumn(column)
Flask appears to prevent PyQt5 UI from updating.
The respective code works properly for either PyQt5 or Flask - but not together. I understand that it may need to do with the way threading is set up.
Any assistance would be greatly appreciated. TIA.
`
import sys
import serial
import threading
from PyQt5.QtWidgets import QWidget, QLabel, QApplication
from flask import Flask, render_template, request, redirect, url_for
app1 = Flask(__name__)
ser = serial.Serial ("/dev/ttyS0", 57600,timeout=3) #Open port with baud rate
count=0
temp = []
class Example(QWidget):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
global count
count = 1
self.setGeometry(300, 300, 250, 150)
self.setWindowTitle('PyQt5 vs Flask')
self.lbl1 = QLabel('Count '+str(count), self)
self.lbl1.move(100, 50)
self.show()
threading.Timer(5,self.refresh).start()
def refresh(self):
global count
count +=1
print("UI ",count)
self.lbl1.setText('Count'+str(count))
threading.Timer(5,self.refresh).start()
def get_uart():
global temp
if ser.inWaiting()>0:
temp =[str(float(x.decode('utf-8'))) for x in ser.read_until().split(b',')]
print(temp)
threading.Timer(1,get_uart).start()
#app1.route("/")
def index():
global temp
templateData = {'temp1' : temp[1] ,'temp2' : temp[2]}
return render_template('index.html',**templateData)
if __name__ == "__main__":
app = QApplication(sys.argv)
pyqt5 = Example()
threading.Timer(1,get_uart).start()
ser.flushInput()
#app1.run(host='0.0.0.0',threaded=True, port=5000) # ,debug=True)
sys.exit(app.exec_())
`
Need to have a UI to control the data analysis to be displayed on Website.
[SOLVED]
All Flask parameters can be defined as:
port = int(os.environ.get('PORT', local_port))
kwargs = {'host': '127.0.0.1', 'port': port , 'threaded' : True, 'use_reloader': False, 'debug':False}
threading.Thread(target=app.run, daemon = True, kwargs=kwargs).start()
and Flask will NOT Block and run with the parameters defined in kwargs.
The better way deal with (possibly waiting) processes, is to use Qt's own threads.
In this example I've created a QObject subclass that does all processing and eventually sends a signal whenever the condition is valid. I can't install flask right now, so I've not tested the whole code, but you'll get the idea.
The trick is to use a "worker" QObject that does the processing. Once the object is created is moved to a new QThread, where it does all its processing without blocking the event loop (thus, the GUI).
You can also create other signals for that object and connect to your slots (which might also be standard python functions/methods outside the QtApplication) which will be called whenever necessary.
class Counter(QtCore.QObject):
changed = QtCore.pyqtSignal(str)
def __init__(self):
super().__init__()
self.count = 0
def run(self):
while True:
self.thread().sleep(1)
if ser.inWaiting() > 0:
self.changed.emit('{}: {}'.format(self.count, [str(float(x.decode('utf-8'))) for x in ser.read_until().split(b',')]))
self.count += 1
class Example(QtWidgets.QWidget):
def __init__(self):
super().__init__()
self.counter = Counter()
self.counterThread = QtCore.QThread()
self.counter.moveToThread(self.counterThread)
self.counterThread.started.connect(self.counter.run)
self.initUI()
def initUI(self):
self.setGeometry(300, 300, 250, 150)
self.setWindowTitle('PyQt5 vs Flask')
self.lbl1 = QtWidgets.QLabel('Count {}'.format(self.counter.count), self)
self.lbl1.move(100, 50)
self.counter.changed.connect(self.lbl1.setText)
self.counterThread.start()
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
pyqt5 = Example()
pyqt5.show()
I think the problem stems from how Flask is activated. If the app.run command is given any parameters (even if in a Thread), then it blocks other commands.
The only way I was able to make Flask and PyQt5 work at the same time, was to activate Flask in a dedicated Thread WITHOUT any parameters - SEE BELOW for the various combinations.
Question: Is this a Flask/Python Bug or Feature or some other explanation related to Development vs Production deployment??
In any case, I would like any help with finding a way to deploy flask in a Port other than 5000 - WITHOUT Flask Blocking other code.
import sys
import serial
import threading
import atexit
from PyQt5.QtWidgets import QWidget, QLabel, QApplication
from flask import Flask, render_template, request, redirect, url_for
ser = serial.Serial ("/dev/ttyS0", 57600,timeout=3) #Open port with baud rate
app = Flask(__name__)
count=0
temp = []
class Example(QWidget):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
global count
count = 1
self.setGeometry(300, 300, 250, 150)
self.setWindowTitle('PyQt5 vs Flask')
self.lbl1 = QLabel("Count "+str(count)+" ", self)
self.lbl1.move(100, 50)
self.show()
threading.Timer(5,self.refresh).start()
def refresh(self):
global count
global str_data
count +=1
self.lbl1.setText("Count "+str(count)+" ")
threading.Timer(0.5,self.refresh).start()
def get_uart():
global temp
if ser.inWaiting()>0:
temp =[str(float(x.decode('utf-8'))) for x in ser.read_until().split(b',')]
print(temp)
threading.Timer(1,get_uart).start()
#app.route("/")
def blank():
global count
data="Count "+str(count)
return data
if __name__ == "__main__":
threading.Timer(5,get_uart).start()
#app.run ## Does not block further execution. Website IS NOT available
#app.run() ## Blocks further execution. Website available at port 5000 without Refresh value
#app.run(port=5123) ## Blocks further execution. Website available at port 5123 without Refresh value
#app.run(threaded=True) ## Blocks further execution. Website available at port 5000 without Refresh value
#threading.Thread(target=app.run()).start() ## Blocks further execution. Website available at port 5000 without Refresh value
#threading.Thread(target=app.run(port=5123)).start() ## Blocks further execution. Website available at port 5123 without Refresh value
#threading.Thread(target=app.run(threaded=True)).start() ## Blocks further execution. Website available at port 5000 without Refresh value
threading.Thread(target=app.run).start() ## Flask DOES NOT block. Website is available at port 5000 with Refresh value
print("Flask does not block")
app1 = QApplication(sys.argv)
pyqt5 = Example()
sys.exit(app1.exec_())
Recently, I'm writing a code about screen recorder. Python3.5+PyQt+Opencv3.2 are used in this program.
I got a problem. When I use the program to record 10 seconds of video, the actual recorded file's video only 5 seconds, and the speed of moving looks faster (maybe 2 times faster).
I don't know why. Is there anyone can help me? Thank you very much!
The main idea of this program is that:
when the start button is clicked, then begin a timer.
in the function captureScreen, capture the screen, then write into the video file.
when the stop button is clicked, then stop the timer
The source code is put here
ui.py
# -*- coding: utf-8 -*-
# Form implementation generated from reading ui file '.\screen_capture.ui'
#
# Created by: PyQt5 UI code generator 5.8.2
#
# WARNING! All changes made in this file will be lost!
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_mainDialog(object):
def setupUi(self, mainDialog):
mainDialog.setObjectName("mainDialog")
mainDialog.resize(200, 42)
mainDialog.setMinimumSize(QtCore.QSize(200, 42))
mainDialog.setMaximumSize(QtCore.QSize(200, 42))
self.horizontalLayout = QtWidgets.QHBoxLayout(mainDialog)
self.horizontalLayout.setObjectName("horizontalLayout")
self.startBtn = QtWidgets.QPushButton(mainDialog)
self.startBtn.setObjectName("startBtn")
self.horizontalLayout.addWidget(self.startBtn)
self.stopBtn = QtWidgets.QPushButton(mainDialog)
self.stopBtn.setObjectName("stopBtn")
self.horizontalLayout.addWidget(self.stopBtn)
self.retranslateUi(mainDialog)
self.startBtn.clicked.connect(mainDialog.startBtn_clicked)
self.stopBtn.clicked.connect(mainDialog.stopBtn_clicked)
QtCore.QMetaObject.connectSlotsByName(mainDialog)
def retranslateUi(self, mainDialog):
_translate = QtCore.QCoreApplication.translate
mainDialog.setWindowTitle(_translate("mainDialog", "Screen Capture"))
self.startBtn.setText(_translate("mainDialog", "开始录制"))
self.stopBtn.setText(_translate("mainDialog", "停止录制"))
mainDialog.py
# -*- coding: utf-8 -*-
__author__ = '350187947#qq.com'
import sys
from PyQt5.QtWidgets import QApplication, QDialog
from PyQt5.QtCore import Qt, QTimer
from ui import *
from PIL import ImageGrab
import numpy as np
import cv2
class MainDialog(QDialog,Ui_mainDialog):
def __init__(self,parent=None):
super(MainDialog,self).__init__(parent)
# UI properties
self.setupUi(self)
self.setWindowFlags(Qt.WindowCloseButtonHint)
self.stopBtn.setEnabled(False)
# video parameter
self.__fps = 25.0
self.__filename = "1stTest.avi"
self.__codecs = cv2.VideoWriter_fourcc(*"XVID")
im = ImageGrab.grab() # capture the screen
frame = np.array(im) # change the frame from Image to np array
self.__height, self.__width, self.__depth = frame.shape # get the shape of the frame
print(self.__height, self.__width, self.__depth)
self.__timer = QTimer(self)
self.__timer.timeout.connect(self.capturing)
def capturing(self):
# self.__timer.setInterval(1000.0 / self.__fps)
frame = self.captureScreen()
self.videoWrite(self.__video,frame)
def setFps(self, fps=25.0):
self.__fps = fps
def setFilename(self, filename):
self.__filename = filename
# 1' create a videowriter
# 2' set timer intervel
# 3' start timer
def startBtn_clicked(self):
self.stopBtn.setEnabled(True)
self.startBtn.setEnabled(False)
self.__video = cv2.VideoWriter(self.__filename, self.__codecs, self.__fps, (self.__width, self.__height), True) # Make a video writer
self.__timer.start(1000/self.__fps)
def stopBtn_clicked(self):
self.__timer.stop()
self.__video.release()
self.stopBtn.setEnabled(False)
self.startBtn.setEnabled(True)
def captureScreen(self):
# capture the screen
im = ImageGrab.grab()
# change the frame from Image to nparray
frame = np.array(im)
# convert the color from BGR to RGB
frame2 = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
return frame2
def videoWrite(self,video,frame):
if not type(video)==type(cv2.VideoWriter()):
raise TypeError('video type ERROR')
if not isinstance(frame,np.ndarray):
raise TypeError('frame type ERROR')
video.write(frame)
if __name__ == '__main__':
'''
main function
'''
app = QApplication(sys.argv)
mainDialog = MainDialog()
mainDialog.show()
sys.exit(app.exec_())
I am currently following this tutorial on threading in PyQt (code from here). As it was written in PyQt4 (and Python2), I adapted the code to work with PyQt5 and Python3.
Here is the gui file (newdesign.py):
# -*- coding: utf-8 -*-
# Form implementation generated from reading ui file 'threading_design.ui'
#
# Created by: PyQt5 UI code generator 5.6
#
# WARNING! All changes made in this file will be lost!
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(526, 373)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.verticalLayout = QtWidgets.QVBoxLayout(self.centralwidget)
self.verticalLayout.setObjectName("verticalLayout")
self.subreddits_input_layout = QtWidgets.QHBoxLayout()
self.subreddits_input_layout.setObjectName("subreddits_input_layout")
self.label_subreddits = QtWidgets.QLabel(self.centralwidget)
self.label_subreddits.setObjectName("label_subreddits")
self.subreddits_input_layout.addWidget(self.label_subreddits)
self.edit_subreddits = QtWidgets.QLineEdit(self.centralwidget)
self.edit_subreddits.setObjectName("edit_subreddits")
self.subreddits_input_layout.addWidget(self.edit_subreddits)
self.verticalLayout.addLayout(self.subreddits_input_layout)
self.label_submissions_list = QtWidgets.QLabel(self.centralwidget)
self.label_submissions_list.setObjectName("label_submissions_list")
self.verticalLayout.addWidget(self.label_submissions_list)
self.list_submissions = QtWidgets.QListWidget(self.centralwidget)
self.list_submissions.setBatchSize(1)
self.list_submissions.setObjectName("list_submissions")
self.verticalLayout.addWidget(self.list_submissions)
self.progress_bar = QtWidgets.QProgressBar(self.centralwidget)
self.progress_bar.setProperty("value", 0)
self.progress_bar.setObjectName("progress_bar")
self.verticalLayout.addWidget(self.progress_bar)
self.buttons_layout = QtWidgets.QHBoxLayout()
self.buttons_layout.setObjectName("buttons_layout")
self.btn_stop = QtWidgets.QPushButton(self.centralwidget)
self.btn_stop.setEnabled(False)
self.btn_stop.setObjectName("btn_stop")
self.buttons_layout.addWidget(self.btn_stop)
self.btn_start = QtWidgets.QPushButton(self.centralwidget)
self.btn_start.setObjectName("btn_start")
self.buttons_layout.addWidget(self.btn_start)
self.verticalLayout.addLayout(self.buttons_layout)
MainWindow.setCentralWidget(self.centralwidget)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "Threading Tutorial - nikolak.com "))
self.label_subreddits.setText(_translate("MainWindow", "Subreddits:"))
self.edit_subreddits.setPlaceholderText(_translate("MainWindow", "python,programming,linux,etc (comma separated)"))
self.label_submissions_list.setText(_translate("MainWindow", "Submissions:"))
self.btn_stop.setText(_translate("MainWindow", "Stop"))
self.btn_start.setText(_translate("MainWindow", "Start"))
and the main script (main.py):
from PyQt5 import QtWidgets
from PyQt5.QtCore import QThread, pyqtSignal, QObject
import sys
import newdesign
import urllib.request
import json
import time
class getPostsThread(QThread):
def __init__(self, subreddits):
"""
Make a new thread instance with the specified
subreddits as the first argument. The subreddits argument
will be stored in an instance variable called subreddits
which then can be accessed by all other class instance functions
:param subreddits: A list of subreddit names
:type subreddits: list
"""
QThread.__init__(self)
self.subreddits = subreddits
def __del__(self):
self.wait()
def _get_top_post(self, subreddit):
"""
Return a pre-formatted string with top post title, author,
and subreddit name from the subreddit passed as the only required
argument.
:param subreddit: A valid subreddit name
:type subreddit: str
:return: A string with top post title, author,
and subreddit name from that subreddit.
:rtype: str
"""
url = "https://www.reddit.com/r/{}.json?limit=1".format(subreddit)
headers = {'User-Agent': 'nikolak#outlook.com tutorial code'}
request = urllib.request.Request(url, header=headers)
response = urllib.request.urlopen(request)
data = json.load(response)
top_post = data['data']['children'][0]['data']
return "'{title}' by {author} in {subreddit}".format(**top_post)
def run(self):
"""
Go over every item in the self.subreddits list
(which was supplied during __init__)
and for every item assume it's a string with valid subreddit
name and fetch the top post using the _get_top_post method
from reddit. Store the result in a local variable named
top_post and then emit a pyqtSignal add_post(QString) where
QString is equal to the top_post variable that was set by the
_get_top_post function.
"""
for subreddit in self.subreddits:
top_post = self._get_top_post(subreddit)
self.emit(pyqtSignal('add_post(QString)'), top_post)
self.sleep(2)
class ThreadingTutorial(QtWidgets.QMainWindow, newdesign.Ui_MainWindow):
"""
How the basic structure of PyQt GUI code looks and behaves like is
explained in this tutorial
http://nikolak.com/pyqt-qt-designer-getting-started/
"""
def __init__(self):
super(self.__class__, self).__init__()
self.setupUi(self)
self.btn_start.clicked.connect(self.start_getting_top_posts)
def start_getting_top_posts(self):
# Get the subreddits user entered into an QLineEdit field
# this will be equal to '' if there is no text entered
subreddit_list = str(self.edit_subreddits.text()).split(',')
if subreddit_list == ['']: # since ''.split(',') == [''] we use that to check
# whether there is anything there to fetch from
# and if not show a message and abort
QtWidgets.QMessageBox.critical(self, "No subreddits",
"You didn't enter any subreddits.",
QtWidgets.QMessageBox.Ok)
return
# Set the maximum value of progress bar, can be any int and it will
# be automatically converted to x/100% values
# e.g. max_value = 3, current_value = 1, the progress bar will show 33%
self.progress_bar.setMaximum(len(subreddit_list))
# Setting the value on every run to 0
self.progress_bar.setValue(0)
# We have a list of subreddits which we use to create a new getPostsThread
# instance and we pass that list to the thread
self.get_thread = getPostsThread(subreddit_list)
# Next we need to connect the events from that thread to functions we want
# to be run when those pyqtSignals get fired
# Adding post will be handeled in the add_post method and the pyqtSignal that
# the thread will emit is pyqtSignal("add_post(QString)")
# the rest is same as we can use to connect any pyqtSignal
self.connect(self.get_thread, pyqtSignal("add_post(QString)"), self.add_post)
# This is pretty self explanatory
# regardless of whether the thread finishes or the user terminates it
# we want to show the notification to the user that adding is done
# and regardless of whether it was terminated or finished by itself
# the finished pyqtSignal will go off. So we don't need to catch the
# terminated one specifically, but we could if we wanted.
self.connect(self.get_thread, pyqtSignal("finished()"), self.done)
# We have all the events we need connected we can start the thread
self.get_thread.start()
# At this point we want to allow user to stop/terminate the thread
# so we enable that button
self.btn_stop.setEnabled(True)
# And we connect the click of that button to the built in
# terminate method that all QThread instances have
self.btn_stop.clicked.connect(self.get_thread.terminate)
# We don't want to enable user to start another thread while this one is
# running so we disable the start button.
self.btn_start.setEnabled(False)
def add_post(self, post_text):
"""
Add the text that's given to this function to the
list_submissions QListWidget we have in our GUI and
increase the current value of progress bar by 1
:param post_text: text of the item to add to the list
:type post_text: str
"""
self.list_submissions.addItem(post_text)
self.progress_bar.setValue(self.progress_bar.value()+1)
def done(self):
"""
Show the message that fetching posts is done.
Disable Stop button, enable the Start one and reset progress bar to 0
"""
self.btn_stop.setEnabled(False)
self.btn_start.setEnabled(True)
self.progress_bar.setValue(0)
QtWidgets.QMessageBox.information(self, "Done!", "Done fetching posts!")
def main():
app = QtWidgets.QApplication(sys.argv)
form = ThreadingTutorial()
form.show()
app.exec_()
if __name__ == '__main__':
main()
Now I'm getting the following error:
AttributeError: 'ThreadingTutorial' object has no attribute 'connect'
Can anyone please tell me how to fix this? Any help would be, as always, very much appreciated.
Using QObject.connect() and similar in PyQt4 is known as "Old style signals", and is not supported in PyQt5 anymore, it supports only "New style signals", which already in PyQt4 was the recommended way to connect signals.
In PyQt5 you need to use the connect() and emit() methods of the bound signal directly, e.g. instead of:
self.emit(pyqtSignal('add_post(QString)'), top_post)
...
self.connect(self.get_thread, pyqtSignal("add_post(QString)"), self.add_post)
self.connect(self.get_thread, pyqtSignal("finished()"), self.done)
use:
self.add_post.emit(top_post)
...
self.get_thread.add_post.connect(self.add_post)
self.get_thread.finished.connect(self.done)
However for this to work you need to explicitly define the add_post signal on your getPostsThread first, otherwise you'll get an attribute error.
class getPostsThread(QThread):
add_post = pyqtSignal(str)
...
In PyQt4 with old style signals when a signal was used it was automatically defined, this now needs to be done explicitly.
I try to create a PyQt application. In order to run process in background and keep the PyQt5 application available for new instruction, I want to use multiprocessing.
On the Windows OS, when I call a function from the Qt MainWindow class with multiprocessing.process, I have an error about pickling this class. But it is running find on Linux.
Here is an example:
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import sys
import multiprocessing
#
from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *
class Frame_main(QMainWindow):
def __init__(self, parent = None):
super(Frame_main, self).__init__(parent)
self.thrd_list=[]
self.initUI()
def initUI(self):
# Button
btn_run = QPushButton('Run', self)
btn_run.clicked.connect(lambda: self.ThdSomething(self.DoRun) ) #
btn_stop = QPushButton('Stop', self)
btn_stop.clicked.connect(self.DoStop)
### TEXT Edit
self.textEdit_term = QTextEdit("terminal: \n ")
self.textEdit_term.append("")
self.textEdit_term.setStyleSheet("color: rgb(255, 255, 255); background-color: black;")
self.textEdit_term.setLineWrapMode(QTextEdit.NoWrap)
self.textEdit_term.setToolTip(' terminal message ')
self.textEdit_term.setStatusTip('textEdit1')
### LAYOUT
Wid_main = QWidget() #
grid_major = QGridLayout() #
grid_major.addWidget( btn_run, 1, 5)
grid_major.addWidget( btn_stop, 2, 5)
Wid_main.setLayout(grid_major)
self.setCentralWidget(Wid_main)
### Affichage
self.show() #
#
def DoRun(self):
print('g starts')
time_start=time.time()
time_stop=time.time()
name='bob'
n=0
while time_stop-time_start <2 :
n+=1
time_stop=time.time()
time.sleep(0.8)
print ('hola', name,n, flush=True)
print('g stops')
def DoStop(self):
''' subourtine kill all the thread '''
print('stop action detected')
while len(self.thrd_list) > 0 :
print("Terminating the job: {}".format(self.thrd[-1].pid) )
os.kill(self.thrd[-1].pid, signal.SIGTERM)
self.thrd_list[-1].terminate()
self.thrd_list.pop()
def ThdSomething(self, job):
''' subourtine to create a new thread to do the job subroutine '''
arg=''
p=multiprocessing.Process(target=job, args=(arg))
self.thrd_list.append( p )
p.start()
print("Start the job GUI: {} with PID: {}".format(str(job) ,self.thrd[-1].pid), file=sys.stdout )
def closeEvent(self, event):
''' subroutine to define what happen when closing the main frame'''
self.statusBar().showMessage('waiting for a respond')
reply = QMessageBox.question(self, 'Message',
"Are you sure to quit?", QMessageBox.Yes |
QMessageBox.No, QMessageBox.No)
if reply == QMessageBox.Yes:
event.accept()
else:
event.ignore()
# Main
if __name__ == '__main__':
# Create QApplication and Main Frame
Qapp = QApplication(sys.argv) # creation de lappli Qt
Qapp.setStyle("fusion") #
frame1 = Frame_main() #
sys.exit(Qapp.exec_()) #
EDIT:
I found several similar case, like :
Python: multiprocessing in pyqt application
but none of them helped. I think this might be linked to fact that my case is using function and attributes of the MainWindow class.
You are correct that this is due to the attempt to fork on a method within the GUI class. Unfortunately windows doesn't really have the ability to fork processes the way linux does, which is why your code works on linux and not on windows. The Python 3 documentation for the multiprocessing library has some useful information on the differences and what the default method for starting a new process is under different platforms.
To answer your question: because your target is a method associated with a GUI object, it has to send the object state to the new process but fails to pickle it because a PyQt GUI object is far too complex to pickle.
If you rewrite your code so that the target function (and args specified) are picklable, your code will work.