在关闭QWdiget窗口时弹出提示框

重写**closeEvent**函数

void closeEvent(QCloseEvent* event) override;

		QMessageBox *msgBox = new QMessageBox(QMessageBox::Question, "信息提示", "是否保存当前数据？", QMessageBox::Save | QMessageBox::No | QMessageBox::Cancel, this, Qt::WindowStaysOnTopHint);
        msgBox->setDefaultButton(QMessageBox::No);
        msgBox->button(QMessageBox::Save)->setText(u8"保存");
        msgBox->button(QMessageBox::No)->setText(u8"不保存");
        msgBox->button(QMessageBox::Cancel)->setText(u8"取消");

        int res = msgBox->exec();
        if (res == QMessageBox::Save)
        {
            model->saveDate();
        }
        else if (res == QMessageBox::Cancel)
        {
            event->ignore();
        }

        delete msgBox;
    	this->close();

通过按钮在点击时弹窗

在按钮对应的槽函数中，适用于无边框的窗口

// 退出系统
void ExitAction(bool state)
{
    if_Data = 0;

    QMessageBox* msgBox = new QMessageBox(QMessageBox::Question, "提示", "退出系统？", QMessageBox::Save /*| QMessageBox::No */ | QMessageBox::Cancel, this, Qt::WindowStaysOnTopHint);
    msgBox->setDefaultButton(QMessageBox::No);
    msgBox->button(QMessageBox::Save)->setText(u8"确定");
    msgBox->button(QMessageBox::Cancel)->setText(u8"取消");

    int res = msgBox->exec();
    if (res == QMessageBox::Save)
    {
        qApp->quit();
    }

    delete msgBox;
}