// Define QActionGroup
QActionGroup *group = new QActionGroup(this);
group->setExclusive(true);
// Add QAction
QAction *action1 = new QAction("Item1", group);
action1->setCheckable(true);
action1->setChecked(true);
ui->menuItem->addAction(action1);
QAction *action2 = new QAction("Item2", group);
action2->setCheckable(true);
ui->menuItem->addAction(action2);
// Connection
connect(group, SIGNAL(triggered(QAction*)), this, SLOT(updateItem(QAction*)));
// Respond function
void QtMainWindow::updateItem(QAction *action)
{
    if (action->text() == "Item1") {
        // TO DO
    }
    if (action->text() == "Item2") {
        // TO DO
    }
}

// Trigger function
void QtMainWindow::on_actionSave_triggered() {
    // TO DO
}