源码

# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file 'qt_checkbox.ui'
#
# Created by: PyQt5 UI code generator 5.15.9
#
# WARNING: Any manual changes made to this file will be lost when pyuic5 is
# run again.  Do not edit this file unless you know what you are doing.


from PyQt5 import QtCore, QtGui, QtWidgets
import sys


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(324, 356)

        self.checkBox = QtWidgets.QCheckBox(MainWindow)
        self.checkBox.setGeometry(QtCore.QRect(20, 20, 91, 19))
        self.checkBox.setObjectName("checkBox")
        self.pushButton = QtWidgets.QPushButton(MainWindow)
        self.pushButton.setGeometry(QtCore.QRect(20, 90, 201, 28))
        self.pushButton.setObjectName("pushButton")
        self.pushButton.clicked.connect(self.getCheckboxStatus)

        self.pushButton_2 = QtWidgets.QPushButton(MainWindow)
        self.pushButton_2.setGeometry(QtCore.QRect(20, 140, 201, 28))
        self.pushButton_2.setObjectName("pushButton_2")
        self.pushButton_2.clicked.connect(self.setCheckboxChecked)
        
        self.pushButton_3 = QtWidgets.QPushButton(MainWindow)
        self.pushButton_3.setGeometry(QtCore.QRect(20, 190, 201, 28))
        self.pushButton_3.setObjectName("pushButton_3")
        self.pushButton_3.clicked.connect(self.setCheckboxUnchecked)
        
        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.checkBox.setText(_translate("MainWindow", "CheckBox"))
        self.pushButton.setText(_translate("MainWindow", "Get Checkbox Status"))
        self.pushButton_2.setText(_translate("MainWindow", "Set Checkbox Checked"))
        self.pushButton_3.setText(_translate("MainWindow", "Set Checkbox Unchecked"))

    def show(self, Form):
        Form.show()

    def messageBox(self,msg):
        msgBox = QtWidgets.QMessageBox()
        msgBox.setIcon(QtWidgets.QMessageBox.Icon.Information)
        msgBox.setWindowTitle("Qt Message Box")
        msgBox.setText(msg)
        msgBox.setStandardButtons(QtWidgets.QMessageBox.Ok | QtWidgets.QMessageBox.Cancel)
        returnValue = msgBox.exec()

    def getCheckboxStatus(self)        :
        if self.checkBox.isChecked():
            self.messageBox("Checkbox is Marked")
        else:
            self.messageBox("Checkbox is Unmarked")
    
    def setCheckboxChecked(self):
        self.checkBox.setChecked(True)

    def setCheckboxUnchecked(self):
        self.checkBox.setChecked(False)

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    Form=QtWidgets.QWidget()    
    main_win = Ui_MainWindow()    
    main_win.setupUi(Form)
    main_win.show(Form)

    sys.exit(app.exec())    

截图：