PyQt UI shows in new window but widgets don't activate signals - user-interface

Question

I've looked through every thread here I could find, but I haven't seen a question like the one I have.
I have a GUI I created in Qt Designer called app_ui.py (after I pyuic5 it). This is the main application window. I created a new window so the user can adjust some settings. This window is called settings_ui.py. Here's the applicable code in the main application for both:
import os
import sys
import glob
from app_ui import Ui_MainWindow
from PyQt5 import QtCore, QtWidgets, QtGui
from PyQt5.QtCore import pyqtSlot
from settings_ui import Ui_Settings
class SettingsWindow(QtWidgets.QMainWindow):
def __init__(self):
# Bring in the ui elements
QtWidgets.QMainWindow.__init__(self)
self.ui = Ui_Settings()
self.ui.setupUi(self)
.
. (application logic here)
.
class ApplicationWindow(QtWidgets.QMainWindow):
def __init__(self):
# Bring in the ui elements
QtWidgets.QMainWindow.__init__(self)
self.ui = Ui_MainWindow()
self.ui.setupUi(self)
self.setWindowTitle(f"{self.windowTitle()} ** Version: {__version__} **")
self.ui.actionSettings.triggered.connect(self.showSettings)
.
. (application logic here)
.
def showSettings(self):
self.winset = QtWidgets.QMainWindow()
self.displaySettings = Ui_Settings()
self.displaySettings.setupUi(self.winset)
self.winset.show()
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
window = ApplicationWindow()
window.show()
sys.exit(app.exec())
Note: I did use super(Window_Name, self).__init__() to initialize my windows in the past, but read somewhere that it's more Pythonic to initialize as QtWidgets.QMainWindow.__init__(self). I don't know if that's true of not, but both ways work.
When I execute the main application and click on the Settings button, the settings window displays as it should, but none of the application logic works (e.g.: You can press buttons, but the connect events don't fire. The style-sheets don't get applied, etc.).
If I pull out the SettingsWindow class into it's own file with the same if __name__ == "__main__" it works as intended.
What am I doing wrong that prevents the Settings Window from working through the main application?
EDIT: Adding minimal reproducible code and making title more descriptive.
Here's the non-working application:
# -*- coding: utf-8 -*-
import os
import sys
import glob
from app_ui import Ui_MainWindow
from PyQt5 import QtCore, QtWidgets, QtGui
from PyQt5.QtCore import pyqtSlot
from settings_ui import Ui_Settings
class SettingsWindow(QtWidgets.QMainWindow):
def __init__(self):
# Bring in the ui elements
QtWidgets.QMainWindow.__init__(self)
self.ui = Ui_Settings()
self.ui.setupUi(self)
self.ui.btnChange.clicked.connect(self.changeColor)
self.colorArray = ['black','blue','red','green']
self.currIndex = 0
def changeColor(self):
style = f"color: {self.colorArray[self.currIndex]}"
if self.currIndex < 2:
self.currIndex += 1
else:
self.currIndex = 0
self.ui.lblChange.setStyleSheet(style)
class ApplicationWindow(QtWidgets.QMainWindow):
def __init__(self):
# Bring in the ui elements
QtWidgets.QMainWindow.__init__(self)
self.ui = Ui_MainWindow()
self.ui.setupUi(self)
self.ui.btnSettings.clicked.connect(self.showSettings)
def showSettings(self):
self.winset = QtWidgets.QMainWindow()
self.displaySettings = Ui_Settings()
self.displaySettings.setupUi(self.winset)
self.winset.show()
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
window = ApplicationWindow()
window.show()
sys.exit(app.exec())
Here's the working standalone SettingsWindow:
# -*- coding: utf-8 -*-
import os
import sys
import glob
from app_ui import Ui_MainWindow
from PyQt5 import QtCore, QtWidgets, QtGui
from PyQt5.QtCore import pyqtSlot
from settings_ui import Ui_Settings
class SettingsWindow(QtWidgets.QMainWindow):
def __init__(self):
# Bring in the ui elements
QtWidgets.QMainWindow.__init__(self)
self.ui = Ui_Settings()
self.ui.setupUi(self)
self.ui.btnChange.clicked.connect(self.changeColor)
self.colorArray = ['black','blue','red','green']
self.currIndex = 0
def changeColor(self):
style = f"color: {self.colorArray[self.currIndex]}"
if self.currIndex < 2:
self.currIndex += 1
else:
self.currIndex = 0
self.ui.lblChange.setStyleSheet(style)
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
window = SettingsWindow()
window.show()
sys.exit(app.exec())
Here's the ui.py files
# -*- coding: utf-8 -*-
# Form implementation generated from reading ui file 'settings.ui'
#
# Created by: PyQt5 UI code generator 5.12.3
#
# WARNING! All changes made in this file will be lost!
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_Settings(object):
def setupUi(self, Settings):
Settings.setObjectName("Settings")
Settings.resize(307, 252)
self.centralwidget = QtWidgets.QWidget(Settings)
self.centralwidget.setObjectName("centralwidget")
self.lblChange = QtWidgets.QLabel(self.centralwidget)
self.lblChange.setGeometry(QtCore.QRect(30, 30, 251, 61))
font = QtGui.QFont()
font.setPointSize(16)
self.lblChange.setFont(font)
self.lblChange.setObjectName("lblChange")
self.btnChange = QtWidgets.QPushButton(self.centralwidget)
self.btnChange.setGeometry(QtCore.QRect(100, 120, 121, 24))
self.btnChange.setObjectName("btnChange")
Settings.setCentralWidget(self.centralwidget)
self.retranslateUi(Settings)
QtCore.QMetaObject.connectSlotsByName(Settings)
def retranslateUi(self, Settings):
_translate = QtCore.QCoreApplication.translate
Settings.setWindowTitle(_translate("Settings", "MainWindow"))
self.lblChange.setText(_translate("Settings", "This should change colors"))
self.btnChange.setText(_translate("Settings", "Change Color"))
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
Settings = QtWidgets.QMainWindow()
ui = Ui_Settings()
ui.setupUi(Settings)
Settings.show()
sys.exit(app.exec_())
# -*- coding: utf-8 -*-
# Form implementation generated from reading ui file 'app.ui'
#
# Created by: PyQt5 UI code generator 5.12.3
#
# 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(800, 600)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.btnSettings = QtWidgets.QPushButton(self.centralwidget)
self.btnSettings.setGeometry(QtCore.QRect(70, 40, 75, 24))
self.btnSettings.setObjectName("btnSettings")
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtWidgets.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 21))
self.menubar.setObjectName("menubar")
MainWindow.setMenuBar(self.menubar)
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", "MainWindow"))
self.btnSettings.setText(_translate("MainWindow", "Settings"))
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_())
Although it's not actually changing any settings, the above code shows the issue I'm having.

Answer 1

Try it:
#import os
import sys
#import glob
from PyQt5 import QtCore, QtWidgets, QtGui
#from PyQt5.QtCore import pyqtSlot
#from settings_ui import Ui_Settings
class Ui_Settings(object):
def setupUi(self, Settings):
Settings.setObjectName("Settings")
Settings.resize(307, 252)
self.centralwidget = QtWidgets.QWidget(Settings)
self.centralwidget.setObjectName("centralwidget")
self.lblChange = QtWidgets.QLabel(self.centralwidget)
self.lblChange.setGeometry(QtCore.QRect(30, 30, 251, 61))
font = QtGui.QFont()
font.setPointSize(16)
self.lblChange.setFont(font)
self.lblChange.setObjectName("lblChange")
self.btnChange = QtWidgets.QPushButton(self.centralwidget)
self.btnChange.setGeometry(QtCore.QRect(100, 120, 121, 24))
self.btnChange.setObjectName("btnChange")
Settings.setCentralWidget(self.centralwidget)
self.retranslateUi(Settings)
QtCore.QMetaObject.connectSlotsByName(Settings)
def retranslateUi(self, Settings):
_translate = QtCore.QCoreApplication.translate
Settings.setWindowTitle(_translate("Settings", "MainWindow"))
self.lblChange.setText(_translate("Settings", "This should change colors"))
self.btnChange.setText(_translate("Settings", "Change Color"))
#from app_ui import Ui_MainWindow
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.btnSettings = QtWidgets.QPushButton(self.centralwidget)
self.btnSettings.setGeometry(QtCore.QRect(70, 40, 75, 24))
self.btnSettings.setObjectName("btnSettings")
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtWidgets.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 21))
self.menubar.setObjectName("menubar")
MainWindow.setMenuBar(self.menubar)
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", "MainWindow"))
self.btnSettings.setText(_translate("MainWindow", "Settings"))
class SettingsWindow(QtWidgets.QMainWindow):
def __init__(self):
QtWidgets.QMainWindow.__init__(self)
self.ui = Ui_Settings()
self.ui.setupUi(self)
self.ui.btnChange.clicked.connect(self.changeColor)
self.colorArray = ['black', 'blue', 'red', 'green']
self.currIndex = 0
def changeColor(self):
style = f"color: {self.colorArray[self.currIndex]}"
if self.currIndex < 2:
self.currIndex += 1
else:
self.currIndex = 0
self.ui.lblChange.setStyleSheet(style)
class ApplicationWindow(QtWidgets.QMainWindow):
def __init__(self):
QtWidgets.QMainWindow.__init__(self)
self.ui = Ui_MainWindow()
self.ui.setupUi(self)
self.ui.btnSettings.clicked.connect(self.showSettings)
def showSettings(self):
# self.winset = QtWidgets.QMainWindow() # ---
# self.displaySettings = Ui_Settings() # ---
# self.displaySettings.setupUi(self.winset) # ---
self.winset = SettingsWindow() # +++
self.winset.show()
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
window = ApplicationWindow()
window.show()
sys.exit(app.exec())
Update
This works, but it doesn't even try to answer my question. What am I doing wrong that prevents the Settings Window from working through the main application?
The UI elements have to stay in their own file, I can't combine everything into a single file.
Nothing prevents the settings window from working through the main application.
You have written the logic in the SettingsWindow cadass, but nowhere do you instantiate this class to use this logic.
I noted in the code what needs to be removed and what needs to be added. You do not need to create an instance of self.displaySettings, since you have already created self.ui in the SettingsWindow class. You just need to create self.winset = SettingsWindow () and that's it.
You can combine everything into one file or use separate files - this does not change the essence.
main.py
#import os
import sys
#import glob
from PyQt5 import QtCore, QtWidgets, QtGui
from PyQt5.QtCore import pyqtSlot
from settings_ui import Ui_Settings
from app_ui import Ui_MainWindow
class SettingsWindow(QtWidgets.QMainWindow):
def __init__(self):
QtWidgets.QMainWindow.__init__(self)
self.ui = Ui_Settings()
self.ui.setupUi(self)
self.ui.btnChange.clicked.connect(self.changeColor)
self.colorArray = ['black', 'blue', 'red', 'green']
self.currIndex = 0
def changeColor(self):
style = f"color: {self.colorArray[self.currIndex]}"
if self.currIndex < 2:
self.currIndex += 1
else:
self.currIndex = 0
self.ui.lblChange.setStyleSheet(style)
class ApplicationWindow(QtWidgets.QMainWindow):
def __init__(self):
QtWidgets.QMainWindow.__init__(self)
self.ui = Ui_MainWindow()
self.ui.setupUi(self)
self.ui.btnSettings.clicked.connect(self.showSettings)
def showSettings(self):
# self.winset = QtWidgets.QMainWindow() # ---
# self.displaySettings = Ui_Settings() # ---
# self.displaySettings.setupUi(self.winset) # ---
self.winset = SettingsWindow() # +++
self.winset.show()
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
window = ApplicationWindow()
window.show()
sys.exit(app.exec())