How can I terminate QStateMachine when QDialog is closed?

问题

I have a QDialog and QStateMachine. This loop terminates when the all aplication is closed but i want to terminate loop when Qdialog is closed. How can i do that?

  QStateMachine sm;
  QState s1(&sm), s2(&sm);
  sm.setInitialState(&s1);
  QEventTransition transition(dialog, QEvent::Close);
  s2.addTransition(&transition);
  QEventLoop loop;
  QObject::connect(&s2, &QState::entered, &loop, &QEventLoop::quit);
  sm.start();
  dialog->show();
  loop.exec();

回答1:

Use QFinalState class for this. At docs example shown usage QPushButton with exit. You just need to connect it with finished() signal for example.

UPD

Some usage example:

MainWinow.h

class MainWindow : public QMainWindow, private Ui::MainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);

private:
    QDialog *dialog;
private slots:
    void on_pushButton_clicked();
};

MainWindow.cpp

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent)
{
    setupUi(this);

    dialog = new QDialog;
}

void MainWindow::on_pushButton_clicked()
{
    // Open dialog after push button was clicked
    if (!dialog)
        dialog = new QDialog;

    QEventLoop loop;
    QStateMachine machine;
    QState *s1 = new QState();

    QFinalState *s2 = new QFinalState();
    s1->addTransition(dialog, SIGNAL(finished(int)), s2);

    connect(&machine, QStateMachine::finished, [&loop]{
        qDebug() << "Finished";
        loop.quit();
    });

    machine.addState(s1);
    machine.addState(s2);
    machine.setInitialState(s1);
    machine.start();


    dialog->show();
    loop.exec();

    qDebug() << "Really finished";
}

So we create QEventLoop, QStateMachine and add states(init state and final state). Then connect QDialog::finished() signal with transition to final state and connect QStateMachine::finished() signal with slot where event loop will be stoped. Then show QDialog and start QStateMachine.

At console will print:

Finished

Realy finished

来源：https://stackoverflow.com/questions/31399044/how-can-i-terminate-qstatemachine-when-qdialog-is-closed

标签

loops

qstatemachine