Python: Access class method variable from another file - python-3.x

Question

I have a PyQt5 GUI code and it has a Ui_MainWindow class and this class has a setupUI method. Here is my gui.py:
import io
import sys
import os
import core as c
from PyQt5 import QtCore, QtGui, QtWidgets, QtWebEngineWidgets
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(1022, 637)
MainWindow.setMinimumSize(QtCore.QSize(1022, 637))
MainWindow.setMaximumSize(QtCore.QSize(1022, 637))
font = QtGui.QFont()
font.setKerning(False)
MainWindow.setFont(font)
MainWindow.setMouseTracking(True)
MainWindow.setFocusPolicy(QtCore.Qt.NoFocus)
.
.
.
self.lineEditSiteX = QtWidgets.QLineEdit(self.centralwidget)
self.actionCalculate.triggered.connect(c.cal) # Here is where I'm stuck!!!!!!!!!!!!!!!!!!!!
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication.instance()
if app is None:
app = QtWidgets.QApplication(sys.argv)
MainWindow = QtWidgets.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())
In the comment above I'm trying to call a function from another file named core.py as as follows:
import gui
def cal():
val = gui.Ui_MainWindow().lineEditSiteX.value()
return val ** (1/val*2)
I simply want when someone clicks on Calculte the lineEdit value will be accessed through the core.py file. But it gives me an attributeError. How can I do it?

Answer 1

You have 2 errors:
Business logic should not depend on the GUI but the GUI should only use business logic.
PyQt recommends creating a class that inherits from the appropriate widget and using the class generated by Qt Designer (for more information read here).
Considering the above, the solution is:
core.py
def cal(val):
return val ** (1/val*2)
gui.py
import io
import sys
import os
import core as c
from PyQt5 import QtCore, QtGui, QtWidgets, QtWebEngineWidgets
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
# ...
self.lineEditSiteX = QtWidgets.QLineEdit(self.centralwidget)
class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
def __init__(self, parent=None):
super().__init__(self, parent)
self.setupUi(self)
self.actionCalculate.triggered.connect(self.on_actionCalculate)
#QtCore.pyqtSlot()
def on_actionCalculate(self):
try:
val = float(self.lineEditSiteX.text())
except ValueError:
print("error")
finally:
res = c.cal(val)
print(res)
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication.instance()
if app is None:
app = QtWidgets.QApplication(sys.argv)
w = MainWindow()
w.show()
sys.exit(app.exec_())