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How to reference & change a PyQt5 window object from another window class or from an extra .py file such as init_events_ui.py

Is it possible to add another .py file (via import) and use it as an initialisation and event handler for a PyQt5 Multiwindow project other window & main .py files?
I have a project that consists of the following files:
main.py - the main app which imports the Ui...py files below & the ui_init_events.py file also
main.py - the main program
Ui_main_window_ui.py - a complied Qt UI to display the main window
Ui_frmConsoleLog_ui.py - a complied Qt UI to display a window with a textEdit & comboBox objects
ui_init_events.py - I want this file to have functions for setting each windows Ui object fields as well as contain the Ui windows object events such as btn.clicked.connect(self.SomeotherFunc)
I have found both these posts helpful but am stuck as I do not know how to reference objects other than the self object and can't find where this is explained. See: PyQt: Modifying Widget Object from another Function
Multiple Windows in PyQt4
In the 2nd post they are using multi-windows (via the QDialog) object also, however they are only using a single .py file. I am using Visual Studio Code & have built the Ui files then complied them. They are works in progress so I expect to make more changes meaning they wil be overwritten so I do not want to edit these files.
I cannot work out how to reference and change the properties in another window for initialisation purposes. The thread is:
Here is the main bits. Currently I call a function to return some data using self.combobox.additems (see #1) but I think calling this over and over again from main.py somewhat decreases code readability.
(#2) Therefore I would like advice how to move all the initialisation parts of an existing PyQt window (being an imported .py file used to generate the window + controls) into a separate .py file (eg named ui_init_events.py).
However in trying & researching this I do not know nor can find an example how to reference the objects using their full hierarchical naming convention. I have tried Application. QWindow., etc. I only know how to use self.... and it isn't working (of course as that would be the referring to the function itself I understand that its being called in, not the PyQt window I'm wanting to reference). See (#3) for what is not working.
Any ideas please on resources available to assist with understanding how PyQt labels its objects from the root of the object tree is appreciated as well as an example of how to set the comboBox_Selector in the Ui_frmConsoleLog window from app.py or another .py file other than from the Ui_frmConsoleLog_ui.py or within the class definition under --init--(self, parent=None): ?
The desired file structure is like this:
+-- main.py (or app.py)
|
+--- Ui_main_window_ui.py (has setupui & adds objects for main window)
|
+--- Ui_main_window_init.py (has init code for Ui_main_window_ui.py)
|
+--- Ui_main_window_events.py (has event code for Ui_main_window_ui.py)
|
+--- Ui_frmConsoleLog_ui.py (has setupui & adds objects for 2nd window)
|
+--- Ui_frmConsoleLog_init.py (has init code for Ui_frmConsoleLog_ui.py)
|
+--- Ui_frmConsoleLog_events.py (has event code for Ui_frmConsoleLog_ui.py)
main.py file contents
# Default imports
import sys, os, io, sched, time
import ui_resources_rc
from PyQt5.QtCore import QObject, QThread, pyqtSignal
from configparser import ConfigParser
...a portion of code here uses a ini config file for retrieving/saving some settings of the UI & I want to set the properties for each object accordingly...
from PyQt5.QtWidgets import (QApplication, QDialog, QMainWindow, QMessageBox, QWidget)
from PyQt5.uic import loadUi
from Ui_main_window_ui import Ui_MainWindow
from Ui_frmConsoleLog_ui import Ui_frmConsoleLog
from ui_init_events import (funcUpdateFormCombos)
...todo... open a network connection to the system (its an inverter)
# This window will be used for filtering network poll event types
class ConsoleLogWindow(QWidget, Ui_frmConsoleLog):
def __init__(self):
super().__init__()
self.setWindowTitle('Console Log')
class AppWindow(QMainWindow, Ui_MainWindow):
def __init__(self, parent=None):
super().__init__(parent)
self.win = None # No Console Log window visible yet.
self.setupUi(self)
#(1) Here is where I will have to call this a lot of times to
# populate the vaious window objects which I dont want to do
self.comboBox_Selector.addItems(funcUpdateFormCombos())
self.action_Console.triggered.connect(self.OpenConsoleLogWindow)
self.action_About.triggered.connect(self.about)
# Populate the controls as per the config file
#initialise() <-- (2) Here is where I want to call a
# function in ui_init_events.py to setup
# the form's objects as created in QtDesigner
# & exported as a .py file. I want to continue
# to edit each PyQt window later so I dont want
# to add to the Ui_... files themselves but in
# main.py call a function that has the code to
# set the object fields like checked, combobox
# list contents, etc.
def OpenConsoleLogWindow(self, checked):
if self.win is None:
self.win = ConsoleLogWindow()
self.win.show()
else:
self.win.close() # Close window.
self.win = None # Discard reference.
if __name__ == "__main__":
app = QApplication(sys.argv)
win = AppWindow()
win.show()
print('HERE')
sys.exit(app.exec())
ui_init_events.py file contents (this is the file I want to house all window object setup without editing the PyQt UI converted .ui to .py files such as Ui_main_window_u.py & Ui_frmConsoleLog_ui.py which I don't want to edit at all.
# Contains the initialisation of widgets fields
def funcUpdateFormCombos():
LIST = ['Amps', 'Volts', 'Watts']
LIST.sort()
return tuple(LIST)
# Would prefer to have a single file per Ui_...py file that houses
# all the events that get triggered for each Ui windows.
# How is this done? eg: <not working> (3)
def initialise()
frmConsoleLog.self.comboBox_Selector.addItems('Watts','Amps','Volts')
Contents of Ui_frmConsoleLog_ui.py (has the combobox I want to populate)
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_frmConsoleLog(object):
def setupUi(self, frmConsoleLog):
frmConsoleLog.setObjectName("frmConsoleLog")
frmConsoleLog.resize(640, 468)
frmConsoleLog.setToolTip("")
frmConsoleLog.setStatusTip("")
frmConsoleLog.setAccessibleName("")
self.horizontalLayout = QtWidgets.QHBoxLayout(frmConsoleLog)
self.horizontalLayout.setContentsMargins(0, 1, 0, 0)
self.horizontalLayout.setObjectName("horizontalLayout")
self.comboBox_Selector = QtWidgets.QComboBox(frmConsoleLog)
self.comboBox_Selector.setObjectName("comboBox_Selector")
self.horizontalLayout.addWidget(self.comboBox_Selector)
self.textEdit_ConsoleLog = QtWidgets.QTextEdit(frmConsoleLog)
self.textEdit_ConsoleLog.setEnabled(True)
sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Fixed, QtWidgets.QSizePolicy.Fixed)
sizePolicy.setHorizontalStretch(0)
sizePolicy.setVerticalStretch(0)
sizePolicy.setHeightForWidth(self.textEdit_ConsoleLog.sizePolicy().hasHeightForWidth())
self.textEdit_ConsoleLog.setSizePolicy(sizePolicy)
self.textEdit_ConsoleLog.setObjectName("textEdit_ConsoleLog")
self.horizontalLayout.addWidget(self.textEdit_ConsoleLog)
self.retranslateUi(frmConsoleLog)
QtCore.QMetaObject.connectSlotsByName(frmConsoleLog)
def retranslateUi(self, frmConsoleLog):
_translate = QtCore.QCoreApplication.translate
frmConsoleLog.setWindowTitle(_translate("frmConsoleLog", "Console Log"))

Worked it out, thanks to an answer in my previous post (that the poster removed?), here's the snippet that works and allows your functions in another .py file to set MainWindow pyQt object control properties in the parent main.py file for a much tidier project. I honestly don't care that professional devs think that is not good practice (if they do they are very closed minded).
In app.py (or main.py - I had two files and was playing with names)
class AppWindow(QMainWindow, Ui_MainWindow):
def __init__(self, parent=None):
super().__init__(parent)
self.win = None # No Console Log window visible yet.
self.setupUi(self)
from init_Ui_main_window import (initMainWindow)
initMainWindow(self)
...
In init_Ui_main_window.py:
def initMainWindow(window):
funcLoadConfig()
# Populate the controls in the main window
window.line_Settings_Simple_Default_Selection.setText(str(SETTINGS_SIMPLE_DEFAULT_SELECTOR))
Note: SETTINGS_SIMPLE_DEFAULT_SELECTOR is a globally defined static variable that wont ever be changed as its read from a config ini file. The user will be able to change the line value if they want to override the default, but it's nice to have a default value populated.
Was that easy as when initMainWindow(self) is called self from the previous object context is passed across to the function and set in function variable window, so to reference the main windows objects its just a case of referencing window.[object name as one would in main.py]

How can I make my PyQt5 app oney one instance?

What I want to achieve:
when I run application from start menu, app starts (if app not running).
If an app is already running, then don't create another instance, just show the previous running app window.
What I've tried:
created a .txt file in a directory, write 'running' & 'not running' into the file while opening & exiting the window. And checking the file contents at very start. For ex:
When starting app: 1.) Check the file content, 2.) If file content is 'running', show warning & exit the app 3.) If file content is 'not running', write 'running' into the file & start app 4.) Write 'not running' into the file on exit.
Issues I'm facing:
This method doesn't feel like the right way to achieve this.
If file item says 'not running', app shows warning and exits. While I want it to show already running instance.
File items not updated to 'not running' when app exits because of some error in code (because that part is never reached due to error)
Can anybody please help me out regarding this?

You can achieve something similar with the win32gui module. To install it type into CMD pip install pywin32. Now this is the code:
from win32 import win32gui
import sys
def windowEnumerationHandler(hwnd, top_windows):
top_windows.append((hwnd, win32gui.GetWindowText(hwnd)))
top_windows = []
win32gui.EnumWindows(windowEnumerationHandler, top_windows)
for i in top_windows:
if "Program" in i[1]: #CHANGE PROGRAM TO THE NAME OF YOUR WINDOW
win32gui.ShowWindow(i[0],5)
win32gui.SetForegroundWindow(i[0])
sys.exit()
from PyQt5.QtWidgets import QApplication, QWidget
def main():
#YOUR PROGRAM GOES HERE
app = QApplication(sys.argv)
w = QWidget()
w.setGeometry(500, 500, 500, 500)
w.setWindowTitle('Simple')
w.show()
sys.exit(app.exec_())
if __name__ == '__main__':
main()
Basically, at the beginning, the program gets the name of every open window. If the window name is equal to the name of the program, then it brings the program to the front and closes the program. If not, then it opens a new program.
PyWin32 link
Stack Overflow get a list of every open window

This solution doesn't require you to install win32 or any other module, works with PyQt5 package itself.
import sys
from PyQt5 import QtWidgets
from PyQt5.QtCore import QSystemSemaphore, QSharedMemory
from ui import window_ui # .py file compiled from .ui file
class LoginWindow(QtWidgets.QMainWindow):
def __init__(self):
super().__init__()
self.ui = window_ui.Ui_MainWindow() # call to init ui
self.ui.setupUi(self)
def launch():
app = QtWidgets.QApplication(sys.argv) # create app instance at top, to able to show QMessageBox is required
window_id = 'pingidapplication'
shared_mem_id = 'pingidsharedmem'
semaphore = QSystemSemaphore(window_id, 1)
semaphore.acquire() # Raise the semaphore, barring other instances to work with shared memory
if sys.platform != 'win32':
# in linux / unix shared memory is not freed when the application terminates abnormally,
# so you need to get rid of the garbage
nix_fix_shared_mem = QSharedMemory(shared_mem_id)
if nix_fix_shared_mem.attach():
nix_fix_shared_mem.detach()
shared_memory = QSharedMemory(shared_mem_id)
if shared_memory.attach(): # attach a copy of the shared memory, if successful, the application is already running
is_running = True
else:
shared_memory.create(1) # allocate a shared memory block of 1 byte
is_running = False
semaphore.release()
if is_running: # if the application is already running, show the warning message
QtWidgets.QMessageBox.warning(None, 'Application already running',
'One instance of the application is already running.')
return
# normal process of creating & launching MainWindow
window = LoginWindow()
window.show()
sys.exit(app.exec_())
if __name__ == '__main__':
launch()
This solution I converted from a C++ code posted on this website originally.

PyQt WebEngineView interferes with MainMenu

I'm trying to create an application that contains a web browser within it, but when I add the web browser my menu bar visually disappears but functionally remains in place. The following are two images, one showing the "self.centralWidget(self.web_widget)" commented out, and the other allows that line to run. If you run the example code, you will also see that while visually the entire web page appears as if the menu bar wasn't present, you have to click slightly below each entry field and button in order to activate it, behaving as if the menu bar was in fact present.
Web Widget Commented Out
Web Widget Active
Example Code
import os
import sys
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
from PyQt5.QtWebEngineWidgets import *
class WebPage(QWebEngineView):
def __init__(self, parent=None):
QWebEngineView.__init__(self)
self.current_url = ''
self.load(QUrl("https://facebook.com"))
self.loadFinished.connect(self._on_load_finished)
def _on_load_finished(self):
print("Url Loaded")
class MainWindow(QMainWindow):
def __init__(self, parent=None):
# Initialize the Main Window
super(MainWindow, self).__init__(parent)
self.create_menu()
self.add_web_widet()
self.show()
def create_menu(self):
''' Creates the Main Menu '''
self.main_menu = self.menuBar()
self.main_menu_actions = {}
self.file_menu = self.main_menu.addMenu("Example File Menu")
self.file_menu.addAction(QAction("Testing Testing", self))
def add_web_widet(self):
self.web_widget = WebPage(self)
self.setCentralWidget(self.web_widget)
if __name__ == "__main__":
app = QApplication(sys.argv)
main_window = MainWindow()
main_window.showMaximized()
sys.exit(app.exec_()) # only need one app, one running event loop
Development Environment
Windows 10, PyQt5, pyqt5-5.9
EDIT
The problem doesn't seem to be directly related to the menu bar. Even removing the menu bar the issue still occurs. That said, changing from showMaximized() to showFullScreen() does seem to solve the problem.

I no longer believe this is an issue with PyQt5 specifically but rather a problem with the graphics driver. Specifically, if you look at Atlassian's HipChat application it has a similar problem which is documented here:
https://jira.atlassian.com/browse/HCPUB-3177
Some individuals were able to solve the problem by running the application from the command prompt with the addendum "--disable-gpu" but that didn't work for my python application. On the other hand, rolling back the Intel(R) HD Graphics Driver did solve my problem. Version 21.20.16.4627 is the one that seems to be causing problems.

Pressing button in QFileDialog popup exits application

I made the transition from PyQt4to PyQt5. My app (created with QtDesigner) has a checkbox which enables a "Save" button, in case you want to save your file. In PyQt4 the dialog would open, I'd choose my file, press OK, done. I implemented a check on the OK button of the main application that would prompt an error if the path was invalid, e.g. if you pressed cancel in the QFileDialog.
With PyQt5 my application exits completely if I close the QFileDialog in any way (OK, cancel, X). I want just the QFileDialog to close and not my main window. How do I do this? Thanks for your time and help.
Here's the relevant part of my code:
self.path = self.ui.savepathButton.pressed.connect(lambda: self.file_save())
def file_save(self):
path = QFileDialog.getSaveFileName(self, "Choose a path and filename", os.getcwd().replace("\\", "/") +
"/test.stl", filter="Stereolithography Files (*.stl)")
self.ui.savepath_label.setText(path) <------ NO ERROR WITHOUT THIS LINE
def OKButton_click(self):
if os.path.isdir(os.path.split(self.ui.savepath_label.text())[0]) is False:
# Warning if the filename is invalid.
file_error = QMessageBox()
file_error.setIcon(QMessageBox.Warning)
file_error.setText("Invalid path or filename.")
file_error.setInformativeText("Please choose a working path and filename.") file_error.setWindowTitle("File name error")
file_error.setStandardButtons(QMessageBox.Ok)
file_error.exec_()
else:
self.accept()
Edit:
I know where my error is located, but I still cannot fix it. I marked the line in the code. Why does self.ui.savepath_label.setText(path) terminate my application?

The PyQt4 provides two different APIs:
API v1 uses the Qt types for objects, so you have to pass things like QString to the setText method
API v2 instead uses python types and the methods of the Qt objects automatically convert those python types into their Qt variants, so you have to pass a python str to them.
This is mentioned in this page about PyQt4. PyQt5 only supports version 2 of the API (that page also mentions other differences).
Also note that according to the question pyqt5 - finding documentation the PyQt5 method getSaveFileName actually returns a pair of (filename, filter) so it's effectively equivalent to PyQt4's getSaveFileNameAndFilter method, which means that you could simply use:
self.ui.savepath_label.setText(path[0])
To set the text. Minimal complete example:
from PyQt5.QtWidgets import QFileDialog, QWidget, QApplication, QHBoxLayout, QPushButton
class Window(QWidget):
def __init__(self):
super(Window, self).__init__(None)
layout = QHBoxLayout()
self.button = QPushButton('click')
layout.addWidget(self.button)
self.setLayout(layout)
self.button.clicked.connect(self.ask_filename)
def ask_filename(self):
fname = QFileDialog.getSaveFileName(self, 'title')
print(fname)
self.button.setText(fname[0])
app = QApplication([])
window = Window()
window.show()
app.exec_()
By the way, if you change fname[0] to fname and try to launch this application from the terminal you get the following helpful error message:
Traceback (most recent call last):
File "test_qt.py", line 15, in ask_filename
self.button.setText(fname)
TypeError: QAbstractButton.setText(str): argument 1 has unexpected type 'tuple'
which tells you that the return type of getSaveFileName is a tuple and not a str.

I finally found the (very small) error:
While PyQt4 apparently writes the path automatically as string, PyQt5 does not.
I changed
self.ui.savepath_label.setText(path)
into
self.ui.savepath_label.setText(str(path))
and all is good now.

Can't get my QT Designer UI to run from script

Ok I hope I can make this understandable...
So I created an UI in QT designer - named heatwindow.ui
Next I wrote this following script in a file named heatwindow.py:
from PySide import QtGui, QtCore, QtUiTools
from HeatModel import *
from vsmutils import *
class HeatWindow:
"""Main window class for the Flow application"""
def __init__(self, app):
"""Class constructor"""
# Assign our application instance as a member variable
self.app = app
# Create an instance of our HeatModel class
#self.heatModel = HeatModel()
# Load and show our user interface
self.ui = loadUiWidget('heatwindow.ui')
self.ui.show()
self.ui.raise_()
if __name__ == '__main__':
app = appInstance()
app.Create()
HeatWindow(app)
window = HeatWindow(app)
app.Run()
Ok, so vsmutils is a script that we got from our teacher...
Anyways - my problem is that nothing happens when running the script. Actually it seems the process in Python gets killed entirely, I have to press "Run again this program" (Spyder) in the Console. When debugging it seems this happens after the line
window = HeatWindow(app)
I hope this is enough info to help me, if not please tell what I should add!
Regards

Ok, solved it finally.
So I am going to post how I did it for others to see if they had the same problem... Cause this was just frustrating.
So- I use Windows 7, Python 2.7.6, Spyder... The script crashed all the time when using QT/Pyside. The solution was to delete a file qt.conf that is inside a Python 2.7.6 folder... And now it works... Don't know why though, but it took me 16 hours to find out.