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How to properly connect QPushButton clicked signal to pyqtSlot

I'm writing a tool with GUI, where I inevitably need to use pyqtSlot. I had errors in this tool, related to its usage and decided to try a minimal example. However, I still fail to figure out the problem.
I've read instructions here. My findings for creation of a custom slot for a pushbutton were the following:
In a class, defining my GUI, I need to create a method, decorated as #pyqtSlot();
I need to write something like self.mybtn.connect(self.<method name>) after button creation.
So, I created a UI in QtDesigner, compiled it and came up with the following code:
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.verticalLayout = QtWidgets.QVBoxLayout(self.centralwidget)
self.verticalLayout.setObjectName("verticalLayout")
self.pushButton = QtWidgets.QPushButton(self.centralwidget)
self.pushButton.setObjectName("pushButton")
self.pushButton.clicked.connect(self.react_to_signal)
self.verticalLayout.addWidget(self.pushButton)
MainWindow.setCentralWidget(self.centralwidget)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
self.pushButton.setText(_translate("MainWindow", "PushButton"))
#QtCore.pyqtSlot()
def react_to_signal(self):
print("Button press signal emitted")
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
MainWindow = QtWidgets.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())
However, when this code is run, it fails for me with the following error:
QObject::connect: Cannot connect QPushButton::clicked(bool) to (nullptr)::react_to_signal()
Traceback (most recent call last):
File "<mypath>/ui_test_slots.py", line 36, in <module>
ui.setupUi(MainWindow)
File "<mypath>/ui_test_slots.py", line 15, in setupUi
self.pushButton.clicked.connect(self.react_to_signal)
TypeError: connect() failed between clicked(bool) and react_to_signal()
Other questions I saw on SO for this problem were caused by usage of the decorated method as a class method, no an instance method. But this doesn't seem to be my case.
What am I missing? What are the real differences between the example I referred to and my code?

PyQt5: Textbox's Not working in windows 11

I recently switched to windows 11 and decided to start a QyQt5 Project, I started to add buttons, which worked. But when I try to type in the textbox it will not display text and not type anything. The only thing it showed was that I had highlighted the textbox. Sadly there is no error or logs showing why it is behaving like this.
This is what happens:
And this is the code that I have used:
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(332, 121)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.Download = QtWidgets.QPushButton(self.centralwidget)
self.Download.setGeometry(QtCore.QRect(240, 70, 75, 23))
self.Download.setObjectName("Download")
self.pushButton = QtWidgets.QPushButton(self.centralwidget)
self.pushButton.setGeometry(QtCore.QRect(20, 70, 75, 23))
self.pushButton.setObjectName("pushButton")
self.linkbox = QtWidgets.QPlainTextEdit(self.centralwidget)
self.linkbox.setGeometry(QtCore.QRect(23, 30, 291, 21))
self.linkbox.setToolTipDuration(-5)
self.linkbox.setLayoutDirection(QtCore.Qt.LeftToRight)
self.linkbox.setInputMethodHints(QtCore.Qt.ImhMultiLine|QtCore.Qt.ImhNoEditMenu)
self.linkbox.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOff)
self.linkbox.setHorizontalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOn)
self.linkbox.setSizeAdjustPolicy(QtWidgets.QAbstractScrollArea.AdjustToContents)
self.linkbox.setTabChangesFocus(True)
self.linkbox.setPlainText("")
self.linkbox.setObjectName("linkbox")
MainWindow.setCentralWidget(self.centralwidget)
self.statusbar = QtWidgets.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "ChaosCapture"))
self.Download.setText(_translate("MainWindow", "Download"))
self.pushButton.setText(_translate("MainWindow", "Options"))
self.linkbox.setPlaceholderText(_translate("MainWindow", "Enter the download link here"))
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
MainWindow = QtWidgets.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())

You're using a very small height for the QPlainTextEdit, and it's completely covered by the horizontal scroll bar (which you've set as always on).
You are also not using layout managers, which is highly discouraged. For instance, the user can resize the window and make it smaller, so the widgets can become partially visible or completely hidden. Layout managers should be always preferred against predetermined geometries.
There are three things that should be done:
set a layout in Designer, in your case a grid layout would be fine: right click on an empty area of the window, open the "Lay out" menu and select "Lay Out in a Grid";
set an arbitrary minimum height for the plain text edit (so that you can resize the window in designer);
in the program script, set a minimum height for the widget based on the font metrics;
Note that the program script must be a separate file, not the one you're showing us (the pyuic file), which must never be manually edited for any reason (read more about using Designer).
The following code assumes that the pyuic file is named ui_mainwindow.py.
from PyQt5 import QtWidgets
from ui_mainwindow import Ui_MainWindow
class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
def __init__(self):
super().__init__()
self.setupUi(self)
self.linkbox.setMinimumHeight(
self.fontMetrics().height() +
self.linkbox.frameWidth() * 2 +
self.linkbox.document().documentMargin() * 2 +
self.linkbox.horizontalScrollBar().sizeHint().height()
)
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
mainWindow = MainWindow()
mainWindow.show()
sys.exit(app.exec_())
Note: hiding the vertical scroll bar is not a very good idea. You either use a QLineEdit, or you should at least make the QPlainTextEdit a bit higher (self.fontMetrics().height() * 2 + ...), otherwise it would be very confusing if the user presses the Enter key by mistake or pastes text with new lines.

Python error with QFileDialog using pyqt5 library

I am trying to create a path browser in pyqt5 using python3 but I have some doubts. My code is this:
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(800, 600)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.horizontalLayoutWidget = QtWidgets.QWidget(self.centralwidget)
self.horizontalLayoutWidget.setGeometry(QtCore.QRect(300, 150, 160, 80))
self.horizontalLayoutWidget.setObjectName("horizontalLayoutWidget")
self.horizontalLayout = QtWidgets.QHBoxLayout(self.horizontalLayoutWidget)
self.horizontalLayout.setObjectName("horizontalLayout")
self.label = QtWidgets.QLabel(self.horizontalLayoutWidget)
self.label.setObjectName("label")
self.horizontalLayout.addWidget(self.label)
self.lineEdit = QtWidgets.QLineEdit(self.horizontalLayoutWidget)
self.lineEdit.setObjectName("lineEdit")
self.horizontalLayout.addWidget(self.lineEdit)
self.toolButton = QtWidgets.QToolButton(self.horizontalLayoutWidget)
self.toolButton.setObjectName("toolButton")
self.horizontalLayout.addWidget(self.toolButton)
MainWindow.setCentralWidget(self.centralwidget)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
# Button action
self.toolButton.pressed.connect(self.selectDirectory(MainWindow, self.lineEdit))
def selectDirectory(self, MainWindow, editText):
editText.setText(str(QtWidgets.QFileDialog.getExistingDirectory(MainWindow, "Select Directory", str(editText.text()))))
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
self.label.setText(_translate("MainWindow", "Path"))
self.toolButton.setText(_translate("MainWindow", "..."))
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
MainWindow = QtWidgets.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())
The idea was using a edittext to write the path to the folder but as helper I want to introduce a button to open a file browser in order to select the directory. To achive this I am trying to use QFileDialog without success. My problem at this moment is when I run my application the QFileDialog is displayed and when I choose a folder the application crash. The first thing I do not want to display the QFileDialog without press the button and the second thing I do not understand why the application is crashing with this error:
Traceback (most recent call last):
File "test.py", line 48, in <module>
ui.setupUi(MainWindow)
File "test.py", line 31, in setupUi
self.toolButton.pressed.connect(self.selectDirectory(MainWindow, self.lineEdit))
TypeError: argument 1 has unexpected type 'NoneType'
Thanks for your help

The signal pressed hopes to connect to a slot that does not expect arguments, so you can not do the direct connection with the selectDirectory() function, you must make the connection using a lambda function.
You must change
self.toolButton.pressed.connect(self.selectDirectory(MainWindow, self.lineEdit))
to
self.toolButton.pressed.connect(lambda m=MainWindow, l=self.lineEdit: self.selectDirectory(m, l))

Qt Python GUI Crashes on Button Click

The code is smaller version I put together to demonstrate what I am trying to do. I just need to get information from a QButtonGroup of radio buttons. Specifically the text of which one has been clicked. However, when I run click the button in the GUI python crashes. There is no error message so I can't pinpoint the cause. Below is the example code, below that is the image show upon clicking a radio button:
Working earlier with a more inefficient method I got to sending commands to the server however the same error occurred when I tried to save the changes to the couchDB document specifically using db.save(doc) command.
# -*- coding: utf-8 -*-
# Form implementation generated from reading ui file 'test.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_Dialog(object):
def setupUi(self, Dialog):
Dialog.setObjectName("Dialog")
Dialog.resize(400, 300)
self.verticalLayoutWidget = QtWidgets.QWidget(Dialog)
self.verticalLayoutWidget.setGeometry(QtCore.QRect(130, 80, 101, 80))
self.verticalLayoutWidget.setObjectName("verticalLayoutWidget")
self.verticalLayout = QtWidgets.QVBoxLayout(self.verticalLayoutWidget)
self.verticalLayout.setContentsMargins(0, 0, 0, 0)
self.verticalLayout.setObjectName("verticalLayout")
self.rad2 = QtWidgets.QRadioButton(self.verticalLayoutWidget)
self.rad2.setObjectName("rad2")
self.group1 = QtWidgets.QButtonGroup(Dialog)
self.group1.setObjectName("group1")
self.group1.addButton(self.rad2)
self.verticalLayout.addWidget(self.rad2)
self.rad3 = QtWidgets.QRadioButton(self.verticalLayoutWidget)
self.rad3.setObjectName("rad3")
self.group1.addButton(self.rad3)
self.verticalLayout.addWidget(self.rad3)
self.rad1 = QtWidgets.QRadioButton(self.verticalLayoutWidget)
self.rad1.setObjectName("rad1")
self.group1.addButton(self.rad1)
self.verticalLayout.addWidget(self.rad1)
self.retranslateUi(Dialog)
QtCore.QMetaObject.connectSlotsByName(Dialog)
def printText(button):
print(button.text())
def retranslateUi(self, Dialog):
_translate = QtCore.QCoreApplication.translate
Dialog.setWindowTitle(_translate("Dialog", "Dialog"))
self.rad2.setText(_translate("Dialog", "RadioButton"))
self.rad3.setText(_translate("Dialog", "RadioButton"))
self.rad1.setText(_translate("Dialog", "RadioButton"))
ui.group1.buttonClicked.connect(self.printText)
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
Dialog = QtWidgets.QDialog()
ui = Ui_Dialog()
ui.setupUi(Dialog)
Dialog.show()
sys.exit(app.exec_())

You need to define the slot with a self argument:
def printText(self, button):
print(button.text())

Qt Framework, PyQt5 and AttributeError: 'MyApp' object has no attribute 'myAttribute'

Last week I started to learn Python and I developed some command line apps. Now I would like to develop apps with GUI. I searched in internet and I found a project that fits my needs: Qt Project (http://qt-project.org) and PyQt (http://www.riverbankcomputing.com/software/pyqt/intro). I installed Qt 5.3.2 Open Source, SIP 4.16.4, PyQt5 5.3.2 on Mac OS X 10.10 and python 2.7.6. After some troubles on installing Qt and PyQt, finally I managed to make them work. If I open example projects from PyQt example folder the gui appears without any problems. So I created my GUI with Qt Creator and then I used pyuic5 to generate python code. This is what pyuic5 created (file name "myapp_auto.py"):
# -*- coding: utf-8 -*-
# Form implementation generated from reading ui file '/Users/andrea/Developer/Qt/mainwindow.ui'
#
# Created: Mon Nov 17 14:20:14 2014
# by: PyQt5 UI code generator 5.3.2
#
# 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(400, 300)
self.centralWidget = QtWidgets.QWidget(MainWindow)
self.centralWidget.setObjectName("centralWidget")
self.ok = QtWidgets.QPushButton(self.centralWidget)
self.ok.setGeometry(QtCore.QRect(140, 120, 115, 32))
self.ok.setAccessibleName("")
self.ok.setObjectName("ok")
self.text = QtWidgets.QLabel(self.centralWidget)
self.text.setGeometry(QtCore.QRect(100, 70, 181, 16))
self.text.setAccessibleName("")
self.text.setAlignment(QtCore.Qt.AlignCenter)
self.text.setObjectName("text")
self.time = QtWidgets.QDateTimeEdit(self.centralWidget)
self.time.setGeometry(QtCore.QRect(100, 180, 194, 24))
self.time.setAccessibleName("")
self.time.setObjectName("time")
MainWindow.setCentralWidget(self.centralWidget)
self.menuBar = QtWidgets.QMenuBar(MainWindow)
self.menuBar.setGeometry(QtCore.QRect(0, 0, 400, 22))
self.menuBar.setObjectName("menuBar")
self.menuMyApp = QtWidgets.QMenu(self.menuBar)
self.menuMyApp.setObjectName("menuMyApp")
self.menuEdit = QtWidgets.QMenu(self.menuBar)
self.menuEdit.setObjectName("menuEdit")
MainWindow.setMenuBar(self.menuBar)
self.mainToolBar = QtWidgets.QToolBar(MainWindow)
self.mainToolBar.setObjectName("mainToolBar")
MainWindow.addToolBar(QtCore.Qt.TopToolBarArea, self.mainToolBar)
self.statusBar = QtWidgets.QStatusBar(MainWindow)
self.statusBar.setObjectName("statusBar")
MainWindow.setStatusBar(self.statusBar)
self.menuBar.addAction(self.menuMyApp.menuAction())
self.menuBar.addAction(self.menuEdit.menuAction())
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
self.ok.setText(_translate("MainWindow", "Ok"))
self.text.setText(_translate("MainWindow", "I\'m a GUI"))
self.menuMyApp.setTitle(_translate("MainWindow", "MyApp"))
self.menuEdit.setTitle(_translate("MainWindow", "Edit"))
After that I added a new python file where I put my code; this is what i wrote (file name "myapp.py"):
#!/usr/bin/env python
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from myapp_auto import Ui_MainWindow
import sys
import time
class MyApp(Ui_MainWindow):
parse_triggered = pyqtSignal()
def __init__(self, parent=None, name=None):
Ui_MainWindow.__init__(self)
if __name__ == "__main__":
app = QApplication(sys.argv)
MainWindow = QMainWindow()
ui = MyApp()
ui.setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())
Then, I run myapp.py and I verified that all GUI elements appeared to be where they should be. Well...now arrive my issue: I tried to access with code the "time" element in MainWindow modifying init def thus:
def __init__(self, parent=None, name=None):
Ui_MainWindow.__init__(self)
# Set the date to now
now = QDateTime()
now.setTime_t(int(time.time()))
self.time.setDateTime(now)
But the compiler shows alway this error:
AttributeError: 'MyApp' object has no attribute 'time'
This happen even if I try to access any other element ("ok", "text").
Will surely be a stupid mistake but I just can not figure out where I went wrong.
Thank you all guys!
Have a good day,
Andrea

You're not far off.
The MyApp class needs to inherit QMainWindow, and you don't need to use the time module. Try something like this:
class MyApp(QMainWindow, Ui_MainWindow):
parse_triggered = pyqtSignal()
def __init__(self, parent=None, name=None):
super(MyApp, self).__init__(parent)
self.setupUi(self)
# Set the date to now
self.time.setDateTime(QDateTime.currentDateTime())
if __name__ == "__main__":
app = QApplication(sys.argv)
window = MyApp()
window.show()
sys.exit(app.exec_())