QStateMachine machine;

QState *s1 = new QState();
QState *s11 = new QState(s1);
QState *s12 = new QState(s1);

QHistoryState *s1h = new QHistoryState(s1);
s1h->setDefaultState(s11);

machine.addState(s1);

QState *s2 = new QState();
machine.addState(s2);

QPushButton *button = new QPushButton();
// Clicking the button will cause the state machine to enter the child state
// that s1 was in the last time s1 was exited, or the history state's default
// state if s1 has never been entered.
s1->addTransition(button, SIGNAL(clicked()), s1h);

Member Function Documentation

QHistoryState::QHistoryState(QHistoryState::HistoryType type, QState *parent = nullptr)

Constructs a new history state of the given type, with the given parent state.

QHistoryState::QHistoryState(QState *parent = nullptr)

Constructs a new shallow history state with the given parent state.

[signal] void QHistoryState::defaultStateChanged()

This signal is emitted when the defaultState property is changed.

This function was introduced in Qt 5.4.

Note: This is a private signal. It can be used in signal connections but cannot be emitted by the user.

Note: Notifier signal for property defaultState.

See also QHistoryState::defaultState.

[signal] void QHistoryState::defaultTransitionChanged()

This signal is emitted when the defaultTransition property is changed.

This function was introduced in Qt 5.6.

Note: This is a private signal. It can be used in signal connections but cannot be emitted by the user.

Note: Notifier signal for property defaultTransition.

See also QHistoryState::defaultTransition.

[signal] void QHistoryState::historyTypeChanged()

This signal is emitted when the historyType property is changed.

This function was introduced in Qt 5.4.

Note: This is a private signal. It can be used in signal connections but cannot be emitted by the user.

Note: Notifier signal for property historyType.

See also QHistoryState::historyType.

[virtual] QHistoryState::~QHistoryState()

Destroys this history state.

QAbstractState *QHistoryState::defaultState() const

Returns this history state's default state. The default state indicates the state to transition to if the parent state has never been entered before.

Note: Getter function for property defaultState.

See also setDefaultState().

QAbstractTransition *QHistoryState::defaultTransition() const

Returns this history state's default transition. The default transition is taken when the history state has never been entered before. The target states of the default transition therefore make up the default state.

This function was introduced in Qt 5.6.

Note: Getter function for property defaultTransition.

See also setDefaultTransition().

[override virtual protected] bool QHistoryState::event(QEvent *e)

Reimplements: QAbstractState::event(QEvent *e).

QHistoryState::HistoryType QHistoryState::historyType() const

Returns the type of history that this history state records.

Note: Getter function for property historyType.

See also setHistoryType().

[override virtual protected] void QHistoryState::onEntry(QEvent *event)

Reimplements: QAbstractState::onEntry(QEvent *event).

[override virtual protected] void QHistoryState::onExit(QEvent *event)

Reimplements: QAbstractState::onExit(QEvent *event).

void QHistoryState::setDefaultState(QAbstractState *state)

Sets this history state's default state to be the given state. state must be a sibling of this history state.

Note that this function does not set state as the initial state of its parent.

Note: Setter function for property defaultState.

See also defaultState().

void QHistoryState::setDefaultTransition(QAbstractTransition *transition)

Sets this history state's default transition to be the given transition. This will set the source state of the transition to the history state.

Note that the eventTest method of the transition will never be called.

This function was introduced in Qt 5.6.

Note: Setter function for property defaultTransition.

See also defaultTransition().

void QHistoryState::setHistoryType(QHistoryState::HistoryType type)

Sets the type of history that this history state records.

Note: Setter function for property historyType.

See also historyType().