QDialog 关闭时如何终止 QStateMachine？

Question

我有一个 QDialog 和 QStateMachine。当所有应用程序关闭时，此循环终止，但我想在 Qdialog 关闭时终止循环。我该怎么做？

  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();

Answer 1

例如使用QFinalState class for this. At docs example shown usage QPushButton with exit. You just need to connect it with finished()信号。

UPD

一些用法示例：

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";
}

所以我们创建 QEventLoop、QStateMachine 并添加状态（初始状态和最终状态）。然后将 QDialog::finished() 信号连接到最终状态，并将 QStateMachine::finished() 信号连接到事件循环将停止的插槽。然后显示QDialog并开始QStateMachine。

在控制台将打印：

Finished

Realy finished

QDialog 关闭时如何终止 QStateMachine？

How can I terminate QStateMachine when QDialog is closed?

qt

loops

qstatemachine