The QState class provides a general-purpose state for QStateMachine. More...

Inheritance diagram for QState:

Public Types
enum	ChildMode

enum	RestorePolicy

Public Signals
void	childModeChanged ()

void	errorStateChanged ()

void	finished ()

void	initialStateChanged ()

void	propertiesAssigned ()

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
	QState (ChildMode childMode, QState *parent=nullptr)

	QState (QState *parent=nullptr)

	~QState ()

QAbstractTransition *	addTransition (QAbstractState *target)

void	addTransition (QAbstractTransition *transition)

template<class SignalClass , class... SignalArgs>
QSignalTransition *	addTransition (QObject sender, void (SignalClass::signal)(SignalArgs...), QAbstractState *target)

void	assignProperty (QObject *object, const QString &name, const QVariant &value)

ChildMode	childMode () const

QAbstractState *	errorState () const

QAbstractState *	initialState () const

void	removeTransition (QAbstractTransition *transition)

void	setChildMode (ChildMode mode)

void	setErrorState (QAbstractState *state)

void	setInitialState (QAbstractState *state)

QList< QAbstractTransition * >	transitions () const

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
	childMode

	errorState

	initialState

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 QState class provides a general-purpose state for QStateMachine. QState objects can have child states, and can have transitions to other states. QState is part of State Machine.

The addTransition() function adds a transition. The removeTransition() function removes a transition. The transitions() function returns the state's outgoing transitions.

The assignProperty() function is used for defining property assignments that should be performed when a state is entered.

Top-level states must be passed a QStateMachine object as their parent state, or added to a state machine using QStateMachine::addState().

States with Child States

The childMode property determines how child states are treated. For non-parallel state groups, the setInitialState() function must be called to set the initial state. The child states are mutually exclusive states, and the state machine needs to know which child state to enter when the parent state is the target of a transition.

The state emits the QState::finished() signal when a final child state (QFinalState) is entered.

The setErrorState() sets the state's error state. The error state is the state that the state machine will transition to if an error is detected when attempting to enter the state (e.g. because no initial state has been set).

See also: propertiesAssigned()

Member Enumeration Documentation

enum QState::ChildMode

This enum specifies how a state's child states are treated.

Constant	Value	Description
`QState::ExclusiveStates`	`0`	The child states are mutually exclusive and an initial state must be set by calling QState::setInitialState().
`QState::ParallelStates`	`1`	The child states are parallel. When the parent state is entered, all its child states are entered in parallel.

enum QState::RestorePolicy

This enum specifies the restore policy type. The restore policy takes effect when the machine enters a state which sets one or more properties. If the restore policy is set to RestoreProperties, the state machine will save the original value of the property before the new value is set.

Later when the machine either enters a state which does not set a value for the given property, the property will automatically be restored to its initial value.

Only one initial value will be saved for any given property. If a value for a property has already been saved by the state machine, it will not be overwritten until the property has been successfully restored.

Constant	Value	Description
`QStateMachine::DontRestoreProperties`	`0`	The state machine should not save the initial values of properties and restore them later.
`QStateMachine::RestoreProperties`	`1`	The state machine should save the initial values of properties and restore them later.

See also: QStateMachine::globalRestorePolicy, QState::assignProperty()

Constructor & Destructor Documentation

QState::QState ( QState * parent = nullptr )

Constructs a new state with the given parent state.

QState::QState	(	ChildMode	childMode,
		QState *	parent = `nullptr`
	)

Constructs a new state with the given childMode and the given parent state.

QState::~QState ( )

Destroys this state object.

Method Documentation

QAbstractTransition * QState::addTransition ( QAbstractState * target )

Adds an unconditional transition from this state to the given target state, and returns then new transition object.

void QState::addTransition ( QAbstractTransition * transition )

Adds the given transition. The transition has this state as the source. This state takes ownership of the transition.

template<class SignalClass , class... SignalArgs>

QSignalTransition * QState::addTransition	(	QObject *	sender,
		void (SignalClass::*)(SignalArgs...)	signal,
		QAbstractState *	target
	)

Adds a transition associated with the given signal of the given sender object, and returns the new QSignalTransition object. The transition has this state as the source, and the given target as the target state.

void QState::assignProperty	(	QObject *	object,
		const QString &	name,
		const QVariant &	value
	)

Instructs this state to set the property with the given name of the given object to the given value when the state is entered.

See also: propertiesAssigned()

ChildMode QState::childMode ( ) const

Returns the child mode of this state.

See also: setChildMode()

void QState::childModeChanged ( )

signal

This signal is emitted when the childMode property is changed.

See also: QState::childMode

QAbstractState * QState::errorState ( ) const

Returns this state's error state.

See also: setErrorState(), QStateMachine::error()

void QState::errorStateChanged ( )

signal

This signal is emitted when the errorState property is changed.

See also: QState::errorState

bool QState::event ( QEvent * event )

overrideprotectedvirtual

Reimplemented from QAbstractState::event()

Reimplemented in QStateMachine::event()

void QState::finished ( )

signal

This signal is emitted when a final child state of this state is entered.

See also: QFinalState

QAbstractState * QState::initialState ( ) const

Returns this state's initial state or nullptr if the state has no initial state.

See also: setInitialState()

void QState::initialStateChanged ( )

signal

This signal is emitted when the initialState property is changed.

See also: QState::initialState

void QState::onEntry ( QEvent * event )

overrideprotectedvirtual

Implements QAbstractState::onEntry()

Reimplemented in QStateMachine::onEntry()

void QState::onExit ( QEvent * event )

overrideprotectedvirtual

Implements QAbstractState::onExit()

Reimplemented in QStateMachine::onExit()

void QState::propertiesAssigned ( )

signal

This signal is emitted when all properties have been assigned their final value. If the state assigns a value to one or more properties for which an animation exists (either set on the transition or as a default animation on the state machine), then the signal will not be emitted until all such animations have finished playing.

If there are no relevant animations, or no property assignments defined for the state, then the signal will be emitted immediately before the state is entered.

See also: QState::assignProperty(), QAbstractTransition::addAnimation()

void QState::removeTransition ( QAbstractTransition * transition )

Removes the given transition from this state. The state releases ownership of the transition.

See also: addTransition()

void QState::setChildMode ( ChildMode mode )

Sets the child mode of this state to mode.

See also: childMode()

void QState::setErrorState ( QAbstractState * state )

Sets this state's error state to be the given state. If the error state is not set, or if it is set to nullptr, the state will inherit its parent's error state recursively. If no error state is set for the state itself or any of its ancestors, an error will cause the machine to stop executing and an error will be printed to the console.

See also: errorState()

void QState::setInitialState ( QAbstractState * state )

Sets this state's initial state to be the given state. The state has to be a child of this state.

See also: initialState()

QList< QAbstractTransition * > QState::transitions ( ) const

Returns this state's outgoing transitions (i.e. transitions where this state is the source state), or an empty list if this state has no outgoing transitions.

See also: addTransition()

Property Documentation

QState::childMode

This property holds the child mode of this state. The default value of this property is QState::ExclusiveStates.

Properties	Class Methods
read	childMode
write	setChildMode
notify	childModeChanged

QState::errorState

This property holds the error state of this state.

Properties	Class Methods
read	errorState
write	setErrorState
notify	errorStateChanged

QState::initialState

This property holds the initial state of this state (one of its child states).

Properties	Class Methods
read	initialState
write	setInitialState
notify	initialStateChanged

Public Types

Public Signals

Public Methods

Protected Methods

Properties

Additional Inherited Members

Detailed Description

States with Child States

Member Enumeration Documentation

Constructor & Destructor Documentation

Method Documentation

Property Documentation