Pyside: QNetworkAccessManager sends no Request - qt

I tried to establish a network connection with PySide (Ubuntu 15.04, Python3.4, PySide 1.2.4). I used the example code from the documentation.
The QNetworkAccessManager does not send the request and I recieve no answer. I checked the Network state with QNetworkSession(QNetworkConfigurationManager().defaultConfiguration()).State() but it says the State is invalid. This seems to make no sense since I am on a desktop pc with a network connection via ethernet cable.
My complete example for the test is the following code:
#!/usr/bin/python3
# -*- coding: utf-8 -*-
import sys
from PySide.QtGui import QApplication
from PySide.QtCore import QUrl
from PySide.QtNetwork import QNetworkAccessManager, QNetworkRequest, QNetworkSession, QNetworkConfigurationManager
def replyFinished(reply):
print(reply)
if __name__ == "__main__":
app = QApplication(sys.argv)
manager = QNetworkAccessManager()
manager.finished.connect(replyFinished)
print(QNetworkSession(QNetworkConfigurationManager().defaultConfiguration()).State())
print("Sending request")
print(manager.get(QNetworkRequest(QUrl("http://www.heise.de/ct/"))))
This prints
PySide.QtNetwork.QNetworkSession.State.Invalid
Sending request
<PySide.QtNetwork.QNetworkReply object at 0x7f4b59c9af08>
but it should display the PySide.QtNetwork.QNetworkReply object twice.

My example was too small. I realized this because of the comment of Pavel Strakhov. I extended it to display a window with a button. By clicking the button it connects successfully. QNetworkSession(QNetworkConfigurationManager().defaultConfiguration()).State() is still invalid but it works.
This is the working code:
#!/usr/bin/python3
# -*- coding: utf-8 -*-
import sys
from PySide.QtGui import QApplication, QWidget, QBoxLayout, QPushButton
from PySide.QtCore import QUrl
from PySide.QtNetwork import QNetworkAccessManager, QNetworkRequest, QNetworkSession, QNetworkConfigurationManager
class Window(QWidget):
def __init__(self):
super().__init__()
self.manager = QNetworkAccessManager()
self.manager.finished.connect(self.reply_finished)
layout = QBoxLayout(QBoxLayout.TopToBottom)
button = QPushButton("connect")
button.clicked.connect(self.network_connect)
layout.addWidget(button)
self.setLayout(layout)
self.setWindowTitle("Network test")
self.setGeometry(100, 100, 200, 150)
self.show()
def network_connect(self):
print(QNetworkSession(QNetworkConfigurationManager().defaultConfiguration()).State())
request = QNetworkRequest(QUrl("http://example.org"))
print("Sending request")
self.manager.get(request)
def reply_finished(self, reply):
print(reply)
print(reply.readData(500))
if __name__ == "__main__":
app = QApplication(sys.argv)
window = Window()
app.exec_()

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How to import external library in QT Python?

I have an issue when importing external python library in QT app.
The program is crashing when I'm trying to import the canlib.
However, no import error is caught, only application communicate appear like this:
program finished with code -1
When I comment out the canlib import, program runs fine.
import os
from pathlib import Path
import sys
import random
from Connection import Connection
from PySide6.QtGui import QGuiApplication
from PySide6.QtQml import QQmlApplicationEngine
from PySide6.QtCore import QTimer
from canlib import kvadblib #here is an error source
if __name__ == "__main__":
app = QGuiApplication(sys.argv)
engine = QQmlApplicationEngine()
# Connection QT <---> Python
connection = Connection()
engine.rootContext().setContextProperty("connection", connection)
# End
# Hardware Init
db = kvadblib.Dbc(filename='battery_monitoring_app.dbc')
ch = communication.open_virtual_channel(1)
# End
engine.load(os.fspath(Path(__file__).resolve().parent / "qml/main.qml"))
if not engine.rootObjects():
sys.exit(-1)
### DO WHILE TRUE STUFF
def doStuff():
connection.testSignalVariable.emit(random.uniform(0.00, 2.00))
### END
timer = QTimer()
timer.timeout.connect(doStuff)
timer.start(100)
sys.exit(app.exec_())

Empty image in QClipboard [duplicate]

I'm trying to run a simple PyQt5 application on Linux, the code is as follows:
#!/usr/bin/python
import sys
from PyQt5.QtWidgets import QApplication, QWidget
def main():
app = QApplication(sys.argv)
w = QWidget()
w.resize(250, 150)
w.move(300, 300)
w.setWindowTitle('Simple')
w.show()
mime = app.clipboard().mimeData()
print(mime.hasImage()) # True
print(mime.imageData()) # None
sys.exit(app.exec_())
if __name__ == '__main__':
main()
Before running it, I copied an image into the clipboard, so mime.hasImage() should return True. No problem, that's also the case. But what's weird is, mime.imageData() sometimes returns None. that shouldn't happen. mime.imageData() should contain the image that I copied instead of None. Is there anything wrong with the code?
By the way, this seems to only happen on Linux, mime.imageData() never returns None on Windows. I'm using python3
That hasImage() returns True does not imply that imageData() returns a QImage since it only indicates that the user copied an image to the clipboard, and in what format do I copy the image? Well, it could be png, jpg, etc or it could provide the url for the client application to download or html to insert it into the client application and then obtain the image by rendering the HTML.
So in general the application from which the image was copied is responsible for the sending format and that there is no restrictive standard for that format but there are common formats.
The following example shows the logic to handle the images that come from urls and HTML:
#!/usr/bin/python
import sys
from functools import cached_property
from PyQt5.QtCore import pyqtSignal, QObject, QUrl
from PyQt5.QtNetwork import QNetworkAccessManager, QNetworkRequest, QNetworkReply
from PyQt5.QtGui import QGuiApplication, QImage, QPixmap
from PyQt5.QtWidgets import QApplication, QWidget, QLabel
from bs4 import BeautifulSoup
class ImageDownloader(QObject):
finished = pyqtSignal(QImage)
def __init__(self, parent=None):
super().__init__(parent)
self.manager.finished.connect(self.handle_finished)
#cached_property
def manager(self):
return QNetworkAccessManager()
def start_download(self, url):
self.manager.get(QNetworkRequest(url))
def handle_finished(self, reply):
if reply.error() != QNetworkReply.NoError:
print("error: ", reply.errorString())
return
image = QImage()
image.loadFromData(reply.readAll())
self.finished.emit(image)
class ClipboardManager(QObject):
imageChanged = pyqtSignal(QImage)
def __init__(self, parent=None):
super().__init__(parent)
QGuiApplication.clipboard().dataChanged.connect(
self.handle_clipboard_datachanged
)
self.downloader.finished.connect(self.imageChanged)
#cached_property
def downloader(self):
return ImageDownloader()
def handle_clipboard_datachanged(self):
mime = QGuiApplication.clipboard().mimeData()
if mime.hasImage():
image = mime.imageData()
if image is not None:
self.imageChanged.emit(image)
elif mime.hasUrls():
url = mime.urls()[0]
self.downloader.start_download(urls[0])
elif mime.hasHtml():
html = mime.html()
soup = BeautifulSoup(html, features="lxml")
imgs = soup.findAll("img")
if imgs:
url = QUrl.fromUserInput(imgs[0]["src"])
self.downloader.start_download(url)
else:
for fmt in mime.formats():
print(fmt, mime.data(fmt))
def main():
app = QApplication(sys.argv)
label = QLabel(scaledContents=True)
label.resize(250, 150)
label.move(300, 300)
label.setWindowTitle("Simple")
label.show()
manager = ClipboardManager()
manager.imageChanged.connect(
lambda image: label.setPixmap(QPixmap.fromImage(image))
)
sys.exit(app.exec_())
if __name__ == "__main__":
main()

Qt Designer Storing and Parsing User Input from Line Edit using Python to Robot Operating System (ROS)

I am currently trying to create a GUI that allows users to type in whatever words they want to be translated into R2-D2's voice.
I have used Qt 5 Designer to create a user input using Line Edit and a button that will publish the user input to a specified topic in ROS. I have also converted it into a python file using pyuic5 -o as r2d2_sound_control.py and I have a main file called main_r2d2_sound_control.py that I will run to initialise the GUI.
How do you store and parse a string from Line Edit using python? I do not know how to declare the string from the user input and parse it when the button is clicked. I'm using pyqt 4
Thank you in advance.
Link to R2-D2 voice package in GitHub https://github.com/koide3/ros2d2
Contents of r2d2_sound_control.py:
# -*- coding: utf-8 -*-
# Form implementation generated from reading ui file 'r2d2_sound_control.ui'
#
# Created by: PyQt5 UI code generator 5.10.1
#
# WARNING! All changes made in this file will be lost!
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_Dialog(object):
def setupUi(self, Dialog):
Dialog.setObjectName("Dialog")
Dialog.resize(505, 114)
self.pushButton_speak = QtWidgets.QPushButton(Dialog)
self.pushButton_speak.setGeometry(QtCore.QRect(300, 40, 89, 25))
self.pushButton_speak.setObjectName("pushButton_speak")
self.lineEdit_speak = QtWidgets.QLineEdit(Dialog)
self.lineEdit_speak.setGeometry(QtCore.QRect(60, 40, 201, 25))
self.lineEdit_speak.setObjectName("lineEdit_speak")
self.retranslateUi(Dialog)
self.pushButton_speak.clicked.connect(Dialog.clicked_speak)
self.lineEdit_speak.returnPressed.connect(Dialog.clicked_speak)
QtCore.QMetaObject.connectSlotsByName(Dialog)
def retranslateUi(self, Dialog):
_translate = QtCore.QCoreApplication.translate
Dialog.setWindowTitle(_translate("Dialog", "Dialog"))
self.pushButton_speak.setText(_translate("Dialog", "Say Out"))
Contents of main_r2d2_sound_control.py
#! /usr/bin/python3
# -*- coding: utf-8 -*-
# GUI
import sys
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
#Import the automatically generated file
from r2d2_sound_control import Ui_Dialog
# ROS
import rospy
from std_msgs.msg import String
class Test(QDialog):
def __init__(self,parent=None):
# GUI
super(Test, self).__init__(parent)
self.ui = Ui_Dialog()
self.ui.setupUi(self)
# ROS pub settings
self.r2d2_sound_controller_String = String()
self.pub_r2d2_sound_controller_speak = rospy.Publisher('/ros2d2_node/speak',String,queue_size=10)
def speak_content(self):
self.input = string(lineEdit_speak)
self.lineEdit_speak.setText(self.text())
def clicked_speak(self):
"""
The slot name specified in Qt Designer.
Write the process you want to execute with the "Say Out" button.
"""
self.r2d2_sound_controller_String.data = text()
self.pub_r2d2_sound_controller_speak.publish(self.r2d2_sound_controller_String)
self.r2d2_sound_controller_String.data = ''
if __name__ == '__main__':
rospy.init_node('r2d2_sound_talker')
app = QApplication(sys.argv)
window = Test()
window.show()
sys.exit(app.exec_())
I have managed to fix it thanks to my friend. I have made the following changes to main_r2d2_sound_control.py
#! /usr/bin/python3
# -*- coding: utf-8 -*-
# GUI
import sys
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
#Import the automatically generated file
from r2d2_head_gripper_sound import Ui_Dialog
# ROS
import rospy
from std_msgs.msg import String
class Test(QDialog):
def __init__(self,parent=None):
# GUI
super(Test, self).__init__(parent)
self.ui = Ui_Dialog()
self.ui.setupUi(self)
# ROS pub settings
self.r2d2_sound_controller_String = String()
self.pub_r2d2_sound_controller_speak = rospy.Publisher('/ros2d2_node/speak',String,queue_size=10)
self.r2d2_sound_controller_String.data = ''
def clicked_speak(self):
"""
The slot name specified in Qt Designer.
Write the process you want to execute with the "Say Out" button.
"""
text = self.ui.lineEdit_speak.text()
self.r2d2_sound_controller_String.data = text
self.pub_r2d2_sound_controller_speak.publish(self.r2d2_sound_controller_String)
if __name__ == '__main__':
rospy.init_node('r2d2_head_and_gripper_talker')
app = QApplication(sys.argv)
window = Test()
window.show()
sys.exit(app.exec_())

How to close Pyqt5 program from QML?

I started a project in Qt Creator initially with a C++ backend, but then switched it to use PyQt5. I have a main.qml, where when I press a button called Exit, I call Qt.quit().
However, I get a General Message stating: Signal QQmlEngine::quit() emitted, but no receivers connected to handle it.
My question is, how do I receive this signal and handle it?
Code:
main.py:
import sys
import PyQt5
from PyQt5 import QtCore
from PyQt5 import QtGui
from PyQt5 import QtQml
from PyQt5.QtCore import QObject pyqtSignal
class DestinyManager,(QtGui.QGuiApplication):
"""the app self"""
def __init__(self, argv):
super(DestinyManager, self).__init__(argv)
# Define a new signal called 'trigger' that has no arguments.
trigger = pyqtSignal()
def connect_and_emit_trigger(self):
# Connect the trigger signal to a slot.
self.trigger.connect(self.handle_trigger)
self.menuItem_Exit.clicked.connect(self.close)
# Emit the signal.
self.trigger.emit()
def handle_trigger(self):
# Show that the slot has been called.
print("trigger signal received")
def main(argv):
app = DestinyManager(sys.argv)
engine = QtQml.QQmlEngine(app)
component = QtQml.QQmlComponent(engine)
component.loadUrl(QtCore.QUrl("exit.qml"))
topLevel = component.create()
if topLevel is not None:
topLevel.show()
else:
for err in component.errors():
print(err.toString())
app.exec()
if __name__ == '__main__':
QObject,main(sys.argv)
Exit.qml:
import QtQuick 2.4
import QtQuick.Controls 1.3
import QtQuick.Window 2.2
Window {
Button {
id: btn_Exit
text: "Exit"
onClicked: Qt.quit();
}
}
There are a few syntax errors in the python script, but ignoring those, the code can be made to work like this:
def main(argv):
app = DestinyManager(sys.argv)
engine = QtQml.QQmlEngine(app)
engine.quit.connect(app.quit)
...
Which is to say, you simply need to connect the qml quit signal to an appropriate slot in your python script.

PyQt5 file dialog not showing up

I have connected a QPushButton to a method that call file dialog. The simplified code look like this:
def init_buttons(self):
self.browse_button = QPushButton('&Browse')
self.browse_button.clicked.connect(self.browse_file)
def browse_file(self):
file_name = QFileDialog.getExistingDirectory()
# Just for checking
print(file_name)
Sometimes QFileDialog won't showing up. The process is indeed running, since the main class/widget doesn't response to my clicking. Sometimes it's showing up.
If QFileDialog doesn't show up, with pycharm, I have to stop and kill process to end the program. If I run the program directly from terminal, I have to manually end the running process to end the program. I can't figure out what causing this, since terminal not showing any exception or warning.
So, what is this?
The parameters for the getExistingDirectory were wrong. Please try this. Also, I have added further information in my pull request.
import os
def browse_file(self):
self.save_dir = QFileDialog.getExistingDirectory(self,
"Open Save Directory", os.path.expanduser('~'))
print(self.save_dir)
#!/usr/bin/python3
# -*- coding: utf-8 -*-
import sys
from PyQt5.QtWidgets import (QMainWindow, QTextEdit,
QAction,QMessageBox, QFileDialog, QApplication,QPushButton,QInputDialog,QLineEdit)
from PyQt5.QtGui import QIcon
class Example(QMainWindow):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.fileName=""
self.text=""
btn1 = QPushButton("Encrypt", self)
btn1.clicked.connect(self.onBtn1)
self.show()
def onBtn1(self):
self.fileName, _ = QFileDialog.getOpenFileName(self, 'Open file', '/Users/Jarvis/Desktop/')
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())

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