QStateMachine* machine = new QStateMachine(this);
    QState* s1 = new QState(machine);
    QMouseEventTransition* mouseTrans =
   new QMouseEventTransition(ui->label, QEvent::MouseButtonRelease,
  Qt::LeftButton, s1);
    QObject::connect(mouseTrans, SIGNAL(triggered()), msgBox, SLOT(show()));
    machine->setInitialState(s1);
    machine->start();