Reloading a PyQt5 App without Restarting it first - python-3.x

Question

I have created an app and on one of the Windows (CreateProjectWindow(QDialog)) I complete a form which I then submit using self.buttonBox.accepted.connect(self.getInfo).
On submission, I want the self.tableComboBox in UpdateProjecWindow(QDialog) automatically and immediately updated without me having to first restart the application. The last four lines of code in CreateProjectWindow(QDialog) is all I have tried but none of them works. Below is snippet of the code:
from __future__ import print_function
from datetime import date
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
from PyQt5.QtGui import *
import sys
import os
import subprocess
import pandas as pd
import time
Class CreateProjectWindow(QDialog):
def __init__(self):
super(CreateProjectWindow, self).__init__()
self.setWindowTitle("Create a new project")
self.setGeometry(100, 100, 300, 400)
self.timeStampLineEdit = QDateTime.currentDateTime().toString('MM-dd-yyyy hh:mm:ss')
self.surnameLineEdit = QLineEdit()
self.firstnameLineEdit = QLineEdit()
self.dateOfBirthLineEdit = QDateEdit(calendarPopup=True, displayFormat='MM-dd-yyyy')
self.createForm()
self.buttonBox = QDialogButtonBox(QDialogButtonBox.Ok | QDialogButtonBox.Cancel)
self.buttonBox.accepted.connect(self.getInfo)
self.buttonBox.rejected.connect(self.reject)
def getInfo():
output = {'timestamp': self.timeStampLineEdit,\
'surname' : self.surnameLineEdit,\
'firstname' : self.firstnameLineEdit,\
'dob' : self.dateOfBirthLineEdit}
df = pd.DataFrame(output, index=[0])
df.to_excel('to/some/local/path/profiles_data.xlsx')
return None
QApplication.processEvents() # attempt 1 but doesn't work
QApplication(sys.argv).reload() # attempt 2 but doesn't work
subprocess.Popen([sys.executable, FILEPATH]) # attempt 3 restarts the app which I don't want
os.execl(sys.executable, sys.executable, * sys.argv) # attempt 4 restarts the app which I don't want.
def creatForm(self):
layout = QFormLayout()
layout.addRow(QLabel("Surname"), self.surnameLineEdit)
layout.addRow(QLabel("First Name"), self.firstnameLineEdit)
layout.addRow(QLabel("D.O.B"), self.dateOfBirthLineEdit)
self.formGroupBox.setLayout(layout)
mainLayout = QVBoxLayout()
mainLayout.addWidget(self.formGroupBox)
mainLayout.addWidget(self.buttonBox)
self.setLayout(mainLayout)
class UpdateProjectWindow(QDialog):
def __init__(self):
super(UpdateProjectWindow, self).__init__()
self.setWindowTitle("Parameter Inputs")
self.setGeometry(100, 100, 300, 400)
self.formGroupBox = QGroupBox("Some Window")
self.tableComboBox = QComboBox()
df = pd.read_excel('to/some/local/path/profiles_data.xlsx')
names = df['surname']
self.tableComboBox.addItems(names)
createForm()
self.buttonBox = QDialogButtonBox(QDialogButtonBox.Ok | QDialogButtonBox.Cancel)
self.buttonBox.accepted.connect(self.processInfo)
self.buttonBox.rejected.connect(self.reject)
mainLayout = QVBoxLayout()
mainLayout.addWidget(self.formGroupBox)
mainLayout.addWidget(self.buttonBox)
self.setLayout(mainLayout)
def processInfo(self):
get_name = self.tableComboBox.currentText()
print(get_name)
def createForm(self):
layout = QFormLayout()
layout.addRow(QLabel("Select Surname"), self.tableComboBox)
self.formGroupBox.setLayout(layout)
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
# setting window title
self.setWindowTitle("MyApp")
# setting geometry to the window
self.setGeometry(200, 200, 400, 10)
self.window1 = CreateProjectWindow()
self.window2 = UpdateProjectWindow()
l = QVBoxLayout()
button1 = QPushButton("Create a Project")
button1.clicked.connect(
lambda checked: self.toggle_window(self.window1)
)
l.addWidget(button1)
button2 = QPushButton("Update a Project")
button2.clicked.connect(
lambda checked: self.toggle_window(self.window2)
)
l.addWidget(button2)
w = QWidget()
w.setLayout(l)
self.setCentralWidget(w)
def toggle_window(self, window):
if window.isVisible():
window.hide()
else:
window.show()
if __name__=="__main__":
app = QApplication(sys.argv)
w = MainWindow()
w.show()
app.exec_()

Answer 1

There is normally no need to restart a Qt application, and certainly this is not required for your case: restarting the QApplication is almost like closing the program and opening it again, doing that just to update some data doesn't make any sense at all.
A possible solution is to create a custom signal for the first window class, which will be emitted when the database is updated, then connect that signal to a function in the other window that loads the data (which means that that function will also be called at the beginning).
class CreateProjectWindow(QDialog):
dataChanged = pyqtSignal()
# ...
def getInfo(self):
# note that your original data was completely wrong, as you tried to add
# the *widgets* to the frame, while you need to add their *values*
output = {'timestamp': self.timeStampLineEdit,
'surname' : self.surnameLineEdit.text(),
'firstname' : self.firstnameLineEdit.text(),
'dob' : self.dateOfBirthLineEdit.date().toString()}
df = pd.DataFrame(output, index=[0])
df.to_excel('to/some/local/path/profiles_data.xlsx')
self.dataChanged.emit()
self.accept()
class UpdateProjectWindow(QDialog):
def __init__(self):
# ...
self.tableComboBox = QComboBox()
self.updateData()
self.createForm()
# ...
def updateData(self):
self.tableComboBox.clear()
df = pd.read_excel('to/some/local/path/profiles_data.xlsx')
names = df['surname']
self.tableComboBox.addItems(names)
class MainWindow(QMainWindow):
def __init__(self):
# ...
self.window1.dataChanged.connect(self.window2.updateData)
Besides that, you must be much more careful with your code: I spent more time to correct your syntax and bugs than to actually give you this answer. Note that there are various other problems with your example, but I will not address them here as it's off topic. In essence, you must put more attention when writing programs.