How to pass variables from one QWizardPage to main QWizard

Question

I am trying to figure out how to pass variables from (e.g.: an openFile function) inside a QWizardPage class to the main QWizard class. I have also read about signals and slots but can't understand how and if this is the ideal way to do it when using PyQt5. Here follows a simplified example of the code:

class ImportWizard(QtWidgets.QWizard):
  def __init__(self, parent=None):
    super(ImportWizard, self).__init__(parent)
    self.addPage(Page1(self))
    self.setWindowTitle("Import Wizard")
    # Trigger close event when pressing Finish button to redirect variables to backend
    self.finished.connect(self.closeEvent)

  def closeEvent(self):
    print("Finish")
    # Return variables to use in main
    print(self.variable)


class Page1(QtWidgets.QWizardPage):

  def __init__(self, parent=None):
    super(Page1, self).__init__(parent)
    self.openFileBtn = QPushButton("Import Edge List")
    layout = QtWidgets.QVBoxLayout()
    layout.addWidget(self.comboBox)
    layout.addWidget(self.openFileBtn)
    self.setLayout(layout)
    self.openFileBtn.clicked.connect(self.openFileNameDialog)

  def openFileNameDialog(self, parent):
    options = QFileDialog.Options()
    options |= QFileDialog.DontUseNativeDialog
    fileName, _ = QFileDialog.getOpenFileName(
        self, "QFileDialog.getOpenFileName()", "",
        "All Files (*);;Python Files (*.py)", options=options)
    # if user selected a file store its path to a variable
    if fileName:
        self.parent.variable = fileName

Answer 1

if you want to access QWizard from QWizardPage you must use the wizard() method, on the other hand closeEvent() is an event that is triggered when the window is closed that should not be invoked by an additional signal that is not necessary, the correct thing is to create a slot that connects to the finished signal.

from PyQt5 import QtCore, QtWidgets

class ImportWizard(QtWidgets.QWizard):
    def __init__(self, parent=None):
        super(ImportWizard, self).__init__(parent)
        self.addPage(Page1(self))
        self.setWindowTitle("Import Wizard")
        # Trigger close event when pressing Finish button to redirect variables to backend
        self.finished.connect(self.onFinished)

    @QtCore.pyqtSlot()
    def onFinished(self):
        print("Finish")
        # Return variables to use in main
        print(self.variable)

class Page1(QtWidgets.QWizardPage):

    def __init__(self, parent=None):
        super(Page1, self).__init__(parent)
        self.openFileBtn = QtWidgets.QPushButton("Import Edge List")
        self.comboBox = QtWidgets.QComboBox()
        layout = QtWidgets.QVBoxLayout()
        layout.addWidget(self.comboBox)
        layout.addWidget(self.openFileBtn)
        self.setLayout(layout)
        self.openFileBtn.clicked.connect(self.openFileNameDialog)


    @QtCore.pyqtSlot()
    def openFileNameDialog(self):
        options = QtWidgets.QFileDialog.Options()
        options |= QtWidgets.QFileDialog.DontUseNativeDialog
        fileName, _ = QtWidgets.QFileDialog.getOpenFileName(
            self, "QFileDialog.getOpenFileName()", "",
            "All Files (*);;Python Files (*.py)", options=options)
        # if user selected a file store its path to a variable
        if fileName:
            self.wizard().variable = fileName


if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = ImportWizard()
    w.show()
    sys.exit(app.exec_())