QSystemTrayIcon

void Dialog::createTrayIcon()
{
    trayIconMenu = new QMenu(this);
    trayIconMenu->addAction(minimizeAction);
    trayIconMenu->addAction(maximizeAction);
    //trayIconMenu->addAction(restoreAction);
    trayIconMenu->addSeparator();
    trayIconMenu->addAction(quitAction);

    trayIcon = new QSystemTrayIcon(this);
    trayIcon->setContextMenu(trayIconMenu);
    trayIcon->setIcon(QIcon(":/images/play.png"));
    trayIcon->setVisible(true);
    trayIcon->show();
}