Provides a means of returning to a previously active substate. More...

Inheritance diagram for QHistoryState:

Public Types
enum	HistoryType

Public Signals
void	defaultStateChanged ()

void	defaultTransitionChanged ()

void	historyTypeChanged ()

Public Signals inherited from QAbstractState
void	activeChanged (bool active)

void	entered ()

void	exited ()

Public Signals inherited from QObject
void	destroyed (QObject *obj=nullptr)

void	objectNameChanged (const QString &objectName)

Public Methods
	QHistoryState (HistoryType type, QState *parent=nullptr)

	QHistoryState (QState *parent=nullptr)

	~QHistoryState ()

QAbstractState *	defaultState () const

QAbstractTransition *	defaultTransition () const

HistoryType	historyType () const

void	setDefaultState (QAbstractState *state)

void	setDefaultTransition (QAbstractTransition *transition)

void	setHistoryType (HistoryType type)

Public Methods inherited from QAbstractState
	~QAbstractState ()

bool	active () const

QStateMachine *	machine () const

QState *	parentState () const

Public Methods inherited from QObject
	QObject (QObject *parent=nullptr)

	~QObject ()

bool	blockSignals (bool block)

const QList< QObject * > &	children () const

bool	connect (const QObject *sender, const QString &signalMethod, const QString &location, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

bool	connect (const QObject *sender, const QString &signalMethod, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

bool	disconnect (const QObject *receiver, const QString &slotMethod=QString ()) const

bool	disconnect (const QString &signalMethod, const QString &location, const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const

bool	disconnect (const QString &signalMethod=QString (), const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const

void	dumpObjectInfo ()

void	dumpObjectTree ()

QList< QString >	dynamicPropertyNames () const

virtual bool	eventFilter (QObject watched, QEvent event)

template<typename T >
T	findChild (const QString &childName=QString ()) const

template<class T >
QList< T >	findChildren (const QRegularExpression &regExp, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

template<class T >
QList< T >	findChildren (const QString &childName=QString (), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

bool	inherits (const QString &className) const

void	installEventFilter (QObject *filterObj)

bool	isWidgetType () const

bool	isWindowType () const

void	killTimer (int id)

const QMetaObject *	metaObject () const

void	moveToThread (QThread *targetThread)

QString	objectName () const

QObject *	parent () const

template<class T = QVariant>
T	property (const QString &name) const

void	removeEventFilter (QObject *obj)

void	setObjectName (const QString &name)

void	setParent (QObject *parent)

bool	setProperty (const QString &name, const QVariant &value)

bool	signalsBlocked () const

int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)

QThread *	thread () const

Protected Methods
bool	event (QEvent *event) override

void	onEntry (QEvent *event) override

void	onExit (QEvent *event) override

Protected Methods inherited from QAbstractState
	QAbstractState (QState *parent=nullptr)

Protected Methods inherited from QObject
virtual void	childEvent (QChildEvent *event)

virtual void	connectNotify (const QMetaMethod &signalMethod) const

virtual void	customEvent (QEvent *event)

virtual void	disconnectNotify (const QMetaMethod &signalMethod) const

bool	isSignalConnected (const QMetaMethod &signalMethod) const

int	receivers (const QString &signal) const

QObject *	sender () const

int	senderSignalIndex () const

virtual void	timerEvent (QTimerEvent *event)

Properties
	defaultState

	defaultTransition

	historyType

Properties inherited from QAbstractState
	active

Properties inherited from QObject
	objectName

Additional Inherited Members
Public Slots inherited from QObject
void	deleteLater ()

Static Public Methods inherited from QObject
static bool	connect (const QObject sender, const QMetaMethod &signalMethod, const QObject receiver, const QMetaMethod &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

static bool	connect (const QObject sender, const QString &signalMethod, const QObject receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection, const QString &location=QString ())

static bool	connect (const QObject sender, const QString &signalMethod, const QString &location, const QObject receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool	connect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver receiver, SlotReturn (SlotClass::slotMethod)(SlotArgs...), Qt::ConnectionType type=Qt::AutoConnection)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool	connect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, T slotLambda, Qt::ConnectionType type=Qt::AutoConnection)

static bool	disconnect (const QObject sender, const QMetaMethod &signalMethod, const QObject receiver, const QMetaMethod &slotMethod)

static bool	disconnect (const QObject sender, const QString &signalMethod, const QObject receiver, const QString &slotMethod)

static bool	disconnect (const QObject sender, const QString &signalMethod, const QString &location, const QObject receiver, const QString &slotMethod)

static bool	disconnect (const QObject sender, std::nullptr_t, const QObject receiver, std::nullptr_t)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver receiver, SlotReturn (SlotClass::slotMethod)(SlotArgs...))

template<class Sender , class SignalClass , class... SignalArgs, class Receiver >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, std::nullptr_t slotMethod=nullptr)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, T slotMethod)

static QMetaObject &	staticMetaObject ()

static QString	tr (const char text, const char comment=nullptr, std::optional< int > numArg=std::optional< int >())

Related Functions inherited from QObject
T	qobject_cast (QObject *object)

	QObjectList

Detailed Description

The QHistoryState class provides a means of returning to a previously active substate.

A history state is a pseudo-state that represents the child state that the parent state was in the last time the parent state was exited. A transition with a history state as its target is in fact a transition to one of the other child states of the parent state. QHistoryState is part of State Machine.

By default a history state is shallow, meaning that it will not remember nested states. This can be configured through the historyType property.

Use the setDefaultState() method to set the state that should be entered if the parent state has never been entered.

QState *s1 = new QState();
QState *s2 = new QState(s1);
 
QHistoryState *s1_hist = new QHistoryState(s1);
s1h->setDefaultState(s2);
 
QStateMachine machine;
machine.addState(s1);
 
QState *s3 = new QState();
machine.addState(s3);
 
// 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.
 
QPushButton *button = new QPushButton();
s1->addTransition(button, SIGNAL(clicked()), s1_hist);

Member Enumeration Documentation

enum QHistoryState::HistoryType

This enum specifies the type of history that a QHistoryState records.

Constant	Value	Description
`QHistoryState::ShallowHistory`	`0`	Only the immediate child states of the parent state are recorded. In this case a transition with the history state as its target will end up in the immediate child state that the parent was in the last time it was exited. This is the default.
`QHistoryState::DeepHistory`	`1`	Nested states are recorded. In this case a transition with the history state as its target will end up in the most deeply nested descendant state the parent was in the last time it was exited.

Constructor & Destructor Documentation

QHistoryState::QHistoryState ( QState * parent = nullptr )

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

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

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

QHistoryState::~QHistoryState ( )

Destroys this history state.

Method Documentation

QAbstractState * QHistoryState::defaultState ( ) const

Returns the value of the defaultState property. The default state indicates the state to transition to if the parent state has never been entered before.

See also: setDefaultState()

void QHistoryState::defaultStateChanged ( )

signal

This signal is emitted when the defaultState property is changed.

See also: QHistoryState::defaultState

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.

See also: setDefaultTransition()

void QHistoryState::defaultTransitionChanged ( )

signal

This signal is emitted when the defaultTransition property is changed.

See also: QHistoryState::defaultTransition

bool QHistoryState::event ( QEvent * event )

overrideprotectedvirtual

Reimplemented from QAbstractState::event()

HistoryType QHistoryState::historyType ( ) const

Returns the value of the defaultType property.

void QHistoryState::historyTypeChanged ( )

signal

This signal is emitted when the historyType property is changed.

See also: QHistoryState::historyType

void QHistoryState::onEntry ( QEvent * event )

overrideprotectedvirtual

Implements QAbstractState::onEntry()

void QHistoryState::onExit ( QEvent * event )

overrideprotectedvirtual

Implements QAbstractState::onExit()

void QHistoryState::setDefaultState ( QAbstractState * state )

Sets this history state's default state to the given state. The state must be a sibling of this QHistoryState. This method does not use the given state for the initial state of its parent.

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. The eventTest method of the transition will never be called.

See also: defaultTransition()

void QHistoryState::setHistoryType ( HistoryType type )

Sets the type of history this QHistoryState records.

See also: historyType()

Property Documentation

QHistoryState::defaultState

This property holds the default state of this history state.

Properties	Class Methods
read	defaultState
write	setDefaultState
notify	defaultStateChanged

QHistoryState::defaultTransition

This property holds the default transition of this history state.

Properties	Class Methods
read	defaultTransition
write	setDefaultTransition
notify	defaultTransitionChanged

QHistoryState::historyType

This property holds the type of history that this history state records. The default value of this property is QHistoryState::ShallowHistory.

Properties	Class Methods
read	historyType
write	setHistoryType
notify	historyTypeChanged

Public Types

Public Signals

Public Methods

Protected Methods

Properties

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Method Documentation

Property Documentation