# 主窗口
class Ui_Record(object):
    def setupUi(self, Dialog):
    ...

# 重点一    
# NewWidget是随便起的名字，QWidget是要重写的，继承给NewWidget
class NewWidget(QWidget):
    def closeEvent(self, event):
        result = QtWidgets.QMessageBox.question(self, "Xpath Robot", "Do you want to exit?", QtWidgets.QMessageBox.Yes | QtWidgets.QMessageBox.No)
        if(result == QtWidgets.QMessageBox.Yes):
            event.accept()
        else:
            event.ignore()

# 重点二
# 主方法里一定要有继承的过程
if __name__ == "__main__":
    app = QApplication(sys.argv)
    qw1 = NewWidget()   # 重写的QWidget组件
    t1 = Ui_Record()   # 正常用的窗口
    t1.setupUi(qw1)   # 一定要继承上
    qw1.show()
    sys.exit(app.exec_())