Qt.CheckState.Checked != 2 and Qt.CheckState.Checked != 0

The PyQt6 documentation says that Qt.CheckState.Unchecked == 0 and Qt.CheckState.Checked == 2.

I wrote a little program to test this, but the result is completely different.

Here is the program code:

from PyQt6.QtCore import Qt
from PyQt6.QtWidgets import QApplication, QMainWindow, QCheckBox


class MainWindow(QMainWindow):
    def __init__(self):
        super(MainWindow, self).__init__()

        self.setWindowTitle("My App")

        self.widget = QCheckBox("CB")
        self.widget.setCheckState(Qt.CheckState.Checked)
        self.widget.stateChanged.connect(self.print_state)

        self.setCentralWidget(self.widget)

    def print_state(self, state):
        print(state)
        print(state == Qt.CheckState.Unchecked)


if __name__ == '__main__':
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec()

But when I click on the checkbox, the following is displayed:

0
False
2
False
0
False
2
False

Why?

Answer

The problem is that you are comparing an int(the value sent by the stateChanged signal) and an enum(Qt.CheckState.Unchecked) so it cannot be compared directly. The solution is to convert the integer to enum:

def print_state(self, state):
    print(Qt.CheckState(state) == Qt.CheckState.Unchecked)