PyQt QCheckBox widget

In this article we will look at the PyQt QCheckBox widget.

The QCheckBox widget provides buttons with two states: on /off. This widget provides a check box with a single text label.

When a check box is selected or disabled, a stateChanged() signal occurs. You can also use the isChecked() method to check if a check box is selected.

Lets look at some of the methods that are available for the QCheckBox widget

Methods/Signals

Examples

Lets look at a basic example

This example has a checkbox and depending on whether the checkbox is checked or not checked, we will change the title bar

    def changeTitle(self, state):
        if state == Qt.Checked:
            self.setWindowTitle('Checkbox checked')
        else:
            self.setWindowTitle('Checkbox not checked')

from PyQt5.QtWidgets import QWidget, QCheckBox, QHBoxLayout, QApplication
from PyQt5.QtCore import Qt
import sys

class Example(QWidget):

    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):

        hbox = QHBoxLayout()

        checkBox1 = QCheckBox('Change title', self)
        checkBox1.toggle()
        checkBox1.stateChanged.connect(self.changeTitle)

        hbox.addWidget(checkBox1)

        self.setLayout(hbox)

        self.setGeometry(300, 300, 350, 250)
        self.setWindowTitle('QCheckBox Example')
        self.show()

    def changeTitle(self, state):
        if state == Qt.Checked:
            self.setWindowTitle('Checkbox checked')
        else:
            self.setWindowTitle('Checkbox not checked')


def main():
    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

You should see something like this

Three-state QCheckBox

One thing you may not be aware of is that you can actually have a tri-state checkbox

If you set the setTristate() method to the checkbox this also allows it to have a ‘no change’ condition’.

You can then use the checkState() method to obtain the status of a check box with three states. In the example below we have adapted the example above.

#!/usr/bin/python
from PyQt5.QtWidgets import (QWidget, QCheckBox, QApplication, 
                             QHBoxLayout, QLabel)
from PyQt5.QtCore import Qt
import sys


class Example(QWidget):

    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):

        hbox = QHBoxLayout()

        checkBox1 = QCheckBox('Change title', self)
        checkBox1.toggle()
        checkBox1.stateChanged.connect(self.changeTitle)
        checkBox1.setTristate(True)
        hbox.addWidget(checkBox1)

        self.setLayout(hbox)

        self.setGeometry(300, 300, 350, 250)
        self.setWindowTitle('QCheckBox Example')
        self.show()

    def changeTitle(self, state):      
        if state == Qt.Checked:
            self.setWindowTitle('Checkbox checked')
        elif state == Qt.Unchecked:
            self.setWindowTitle('Checkbox not checked')
        else:
            self.setWindowTitle('Checkbox - 3rd state')


def main():
    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

This displayed the following