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PyQt QCheckBox widget

by maxguy71

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

Method Description
text() Return the label text of the check box.
setText() Set the label text for the check box.
isChecked() Return the status of the check box. (True/False)
checkState() Return the status of the check box. (2/1/0)
toggle() Change the status of the check box.
pressed() Create signals when the check box is pressed.
released() Create signals when the check box is released.
clicked() Create signals when the check box is clicked.
stateChanged() Create signals when the state of the check box is changed.

 

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

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