How can I return my session variable to my main code with PyQt5?

Question

I don't know how to express my problem in a question because I am a very PyQt5 learner and I don't know the vocabularies, but come on.

I need to return the session_user variable (in the login () function) to my main code. This variable needs to be passed to the main screen after the login is completed, but I don't know of a function in PyQt5 that returns a variable that is not of type int like: accept (), reject (), done ().

Is it possible to return my session_user variable to my main code with some PyQt5 function like the ones I mentioned?

my code:

from PyQt5 import uic, QtWidgets
from PyQt5.QtWidgets import QDialog
from views.ui.login.telaLogin import Ui_Dialog
import sys
from control.exception_login import verification_login_user

class ViewLogin(QDialog):
    def __init__(self):
        super().__init__()
        self.viewlogin = Ui_Dialog()
        self.viewlogin.setupUi(self)

        self.viewlogin.button_login.clicked.connect(self.login)

    def login(self):

        self.login = self.viewlogin.login_login.text() 
        self.password = self.viewlogin.login_password.text()

        erro =  verification_login_user(self.login, self.password)
    
        if (erro == False):
            self.close()
            session_user = (self.login, self.senha) 
            #self.done(r) # I understand its functionality # PROBLEM
            #return (session_user) # PROBLEM
            self.accept() # The problem would end here if I didn't need the variable sessao_user
             
        elif(erro == True):
            self.viewlogin.login_login.setText('')
            self.viewlogin.login_password.setText('')
            

app = QtWidgets.QApplication([])

w = ViewLogin()
result = w.exec_()

print(result)  # desired result = (' login', 'password') 
# real result = 1 

sys.exit(app.exec_())

Answer 1

One of the approaches you could implement is via threading module.

1. Create a class Controller and Daemon to True (this ensures the thread will be killed after the app closes).

class Controller(threading.Thread):

    def __init__(self):
        super(Controller, self).__init__(daemon = True)

        self.my_variable = 0
        self.variables_from_gui = None

2. Overwrite the run method:

    def run(self):
        print("My main loop is here!")

        while True: 
            print("Button presses: {}, Variables from gui: {}".format(self.button_presses, self.variables_from_gui))
            time.sleep(1) #This wont freeze the gui

3. Add a function that will register the button login click:

    def login(self, variables_from_gui = None):
        #Do you login stuff
        self.variables_from_gui = variables_from_gui
        self.button_presses += 1

4. In the App class (in your case that would be the main GUI class) from the login function start a new thread and pass variables to it.

def login(self):
    #Stuff to do in your GUI
    variables_to_send = 0, "Text", {"key" : 10}

    threading.Thread(target = lambda: self.controller.login(variables_from_gui = variables_to_send)).start()

5. Also in your GUI class create a Controller object and start it:

        self.controller = Controller()
        self.controller.start() #Start the run method in the Controller()

---

There are plenty of things that can be done better and make it more Threading safe. But that is outside of this question topic.

---

Whole code:

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton
from PyQt5.QtGui import QIcon
from PyQt5.QtCore import pyqtSlot

import threading
import time

class App(QWidget):

    def __init__(self):
        super().__init__()
        self.left = 10
        self.top = 10
        self.width = 320
        self.height = 200
        self.initUI()
    
    def initUI(self):
        self.controller = Controller()
        self.controller.start() #Start the run method in the Controller()

        self.setGeometry(self.left, self.top, self.width, self.height)
        
        button = QPushButton("My login", self)
        button.move(100,70)
        button.clicked.connect(self.login)
        
        self.show()

    def login(self):
        #Stuff to do in your GUI
        variables_to_send = 0, "Text", {"key" : 10}

        threading.Thread(target = lambda: self.controller.login(variables_from_gui = variables_to_send)).start()

class Controller(threading.Thread):

    def __init__(self):
        super(Controller, self).__init__(daemon = True)

        self.button_presses = 0
        self.variables_from_gui = None

    def run(self):
        print("My main loop is here!")

        while True: 
            print("Button presses: {}, Variables from gui: {}".format(self.button_presses, self.variables_from_gui))
            time.sleep(1) #This wont freeze the gui

    def login(self, variables_from_gui = None):
        #Do you login stuff
        self.variables_from_gui = variables_from_gui
        self.button_presses += 1


if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = App()
    sys.exit(app.exec_())