installEventFilter in PyQt5

Question

I'm trying to implement an event in PyQT5, but i get this error:

TypeError: installEventFilter(self, QObject): argument 1 has unexpected type 'MainWindow_EXEC'

This is my code

import sys
from time import sleep
from PyQt5 import QtCore, QtWidgets
from view_cortes2 import Ui_cortes2enter

class MainWindow_EXEC():
def __init__(self):
    app = QtWidgets.QApplication(sys.argv)
    cortes2 = QtWidgets.QMainWindow()
    self.ui = Ui_cortes2()
    self.ui.setupUi(cortes2)
    self.flag = 0
    self.ui.ledit_corteA.installEventFilter(self)
    self.ui.ledit_corteB.installEventFilter(self)
    self.ui.buttonGroup.buttonClicked.connect(self.handleButtons)
    cortes2.show()
    sys.exit(app.exec_())

def eventFilter(self, source, event):
    if (event.type() == QtCore.QEvent.FocusIn and source is self.ui.ledit_corteA):
        print("A")
        self.flag = 0
    if (event.type() == QtCore.QEvent.FocusIn and source is self.ui.ledit_corteA):
        print("B")
        self.flag = 1
    return super(cortes2, self).eventFilter(source, event)

if __name__ == "__main__":
    MainWindow_EXEC()

The event that I'm trying to add is when I focus in a TextEdit it changes the value of a flag. If i change

self.ui.ledit_corteA.installEventFilter(self)

by

self.ui.ledit_corteA.installEventFilter(cortes2)

I works, but never changes the value of my flag.

Please help.

Answer 1

installEventFilter expects a QObject, and in your case MainWindow_EXEC is not.

If you are using the Qt Designer design it is recommended to create a new class that inherits from the appropriate widget and use the class provided by Qt Designer to fill it as shown below:

import sys
from PyQt5 import QtCore, QtWidgets
from view_cortes2 import Ui_cortes2

class MainWindow(QtWidgets.QMainWindow, Ui_cortes2):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        self.setupUi(self)
        self.flag = 0
        self.ledit_corteA.installEventFilter(self)
        self.ledit_corteB.installEventFilter(self)
        #self.buttonGroup.buttonClicked.connect(self.handleButtons)

    def eventFilter(self, source, event):
        if event.type() == QtCore.QEvent.FocusIn and source is self.ledit_corteA:
            print("A")
            self.flag = 0
        if event.type() == QtCore.QEvent.FocusIn and source is self.ledit_corteB:
            print("B")
            self.flag = 1
        return super(MainWindow, self).eventFilter(source, event)

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    w = MainWindow()
    w.show()
    sys.exit(app.exec_())

References:

• http://pyqt.sourceforge.net/Docs/PyQt5/designer.html