QT5入门之5 - 确认退出对话框

#include <QCloseEvent>//头文件记得添加
void closeEvent(QCloseEvent *event);//头文件中声明
void MainWindow::closeEvent(QCloseEvent *event)
{
   // QMessageBox::StandardButton button;
    int button;
    button = QMessageBox::question(this, tr("退出程序"),
                                   QString(tr("确认退出程序?")),
                                   QMessageBox::Yes | QMessageBox::No);
    if (button == QMessageBox::No) {
          event->ignore();  //忽略退出信号，程序继续运行
    }
    else if (button == QMessageBox::Yes) {
          event->accept();  //接受退出信号，程序退出
    }
}