How to send a signal from a QDialog to a QMainWindow class - multithreading

Question

I have made a UI which includes a mainwindow and a button that opens a dialog window. I want to send the current text changed signal from a line edit in the dialog window to the Mainwindow class as a variable. An example of the code I am making is below:
from PyQt5 import QtCore, QtGui, QtWidgets
from selenium import webdriver
import time
import threading
from bs4 import BeautifulSoup as soup
import requests
class Ui_Dialog(object):
def setupUi(self, Dialog):
Dialog.setObjectName("Dialog")
Dialog.resize(388, 179)
self.lineEdit_2 = QtWidgets.QLineEdit(Dialog)
self.lineEdit_2.setGeometry(QtCore.QRect(100, 100, 271, 21))
font = QtGui.QFont()
font.setFamily("Yu Gothic")
self.lineEdit_2.setFont(font)
self.lineEdit_2.setStyleSheet("background-color: transparent;\n"
"color: rgb(255, 255, 255);")
self.lineEdit_2.setObjectName("lineEdit_2")
class Dialog(QtWidgets.QDialog, Ui_Dialog):
def __init__(self, parent=None):
QtWidgets.QDialog.__init__(self, parent)
self.setupUi(self)
# self.pushButton.pressed.connect(self.textEdit.clear)
# self.pushButton.pressed.connect(self.sejd)
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
self.keyworddict = {}
self.count = {}
MainWindow.setObjectName("MainWindow")
MainWindow.resize(803, 538)
MainWindow.setMinimumSize(QtCore.QSize(0, 0))
MainWindow.setMaximumSize(QtCore.QSize(10000, 10000))
self.centralWidget = QtWidgets.QWidget(MainWindow)
self.centralWidget.setObjectName("centralWidget")
self.pushButton = QtWidgets.QPushButton(self.centralWidget)
self.pushButton.setGeometry(QtCore.QRect(180, 210, 75, 23))
font = QtGui.QFont()
font.setFamily("Yu Gothic")
font.setBold(True)
font.setWeight(75)
self.pushButton.setFont(font)
self.pushButton.setObjectName("pushButton")
MainWindow.setCentralWidget(self.centralWidget)
class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
def __init__(self, parent=None):
QtWidgets.QMainWindow.__init__(self, parent)
self.setupUi(self)
self.pushButton.pressed.connect(self.on_Button_clicked)
def on_Button_clicked(self):
dialog = QtWidgets.QDialog()
dialog.ui = Ui_Dialog()
dialog.ui.setupUi(dialog)
dialog.setWindowTitle("Login")
dialog.setAttribute(QtCore.Qt.WA_DeleteOnClose)
dialog.exec_()
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
w = MainWindow()
w.setWindowTitle("ui")
w.show()
sys.exit(app.exec_())
All help appreciated. I would preferably like an example using the code above.

Answer 1

There are at least two simple ways to do this. You can either connect a signal when the dialog is created, or just retrieve the text after the dialog closes:
class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
...
def dialogTextChanged(self, text):
print(text)
def on_Button_clicked(self):
dialog = QtWidgets.QDialog()
dialog.ui = Ui_Dialog()
dialog.ui.setupUi(dialog)
# connect signal to slot
dialog.ui.lineEdit_2.textChanged.connect(self.dialogTextChanged)
dialog.setWindowTitle("Login")
# this is not needed
# dialog.setAttribute(QtCore.Qt.WA_DeleteOnClose)
dialog.exec_()
# or retrieve text after dialog closes
print(dialog.ui.lineEdit_2.text())
dialog.deleteLater()
If this is a login dialog, you should probably have an accept button which is connected to the dialog's accept() slot. Then you can check the exit status of the dialog like this:
if dialog.exec_() == QtWidgets.QDialog.Accepted:
text = dialog.ui.lineEdit_2.text()
# do sothing with text ...
dialog.deleteLater()