void Window::closeEvent(QCloseEvent *event)
 {
     if (trayIcon->isVisible()) {
         QMessageBox::information(this, tr("Systray"),
                                  tr("The program will keep running in the "
                                     "system tray. To terminate the program, "
                                     "choose <b>Quit</b> in the context menu "
                                     "of the system tray entry."));
         hide();
         event->ignore();
     }
 }
这样子可以吗?你试试