QScxmlStateMachine Class

Member Function Documentation

[protected] QScxmlStateMachine::QScxmlStateMachine(const QMetaObject *metaObject, QObject *parent = nullptr)

Default constructs an instance of QScxmlStateMachine.

[protected] QScxmlStateMachine::QScxmlStateMachine(QScxmlStateMachinePrivate &dd, QObject *parent = nullptr)

Default constructs an instance of QScxmlStateMachine.

QStringList QScxmlStateMachine::activeStateNames(bool compress = true) const

Retrieves a list of state names of all active states.

When a state is active, all its parent states are active by definition. When compress is true (the default), the parent states will be filtered out and only the leaf states will be returned. When it is false, the full list of active states will be returned.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

void QScxmlStateMachine::cancelDelayedEvent(const QString &sendId)

Cancels a delayed event with the specified sendId.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

QMetaObject::Connection QScxmlStateMachine::connectToEvent(const QString &scxmlEventSpec, const typename QtPrivate::FunctionPointer<PointerToMemberFunction>::Object *receiver, PointerToMemberFunction method, Qt::ConnectionType type = Qt::AutoConnection)

Creates a connection of the given type from the event specified by scxmlEventSpec to method in the receiver object.

The receiver's method must take a QScxmlEvent as a parameter.

In contrast to event specifications in SCXML documents, spaces are not allowed in the scxmlEventSpec here. In order to connect to multiple events with different prefixes, connectToEvent() has to be called multiple times.

Returns a handle to the connection, which can be used later to disconnect.

QMetaObject::Connection QScxmlStateMachine::connectToState(const QString &scxmlStateName, const QObject *receiver, const char *method, Qt::ConnectionType type = Qt::AutoConnection)

Creates a connection of the given type from the state identified by scxmlStateName to the method in the receiver object. The receiver's method may take a boolean argument that indicates whether the state connected became active or inactive. For example:

void mySlot(bool active);

Returns a handle to the connection, which can be used later to disconnect.

QMetaObject::Connection QScxmlStateMachine::connectToState(const QString &scxmlStateName, const typename QtPrivate::FunctionPointer<PointerToMemberFunction>::Object *receiver, PointerToMemberFunction method, Qt::ConnectionType type = Qt::AutoConnection)

Creates a connection of the given type from the state specified by scxmlStateName to method in the receiver object.

The receiver's method must take a boolean argument that indicates whether the state connected became active or inactive.

Returns a handle to the connection, which can be used later to disconnect.

QScxmlDataModel *QScxmlStateMachine::dataModel() const

Returns the data model used by the state machine.

Note: Getter function for property dataModel.

See also setDataModel().

[signal] void QScxmlStateMachine::finished()

This signal is emitted when the state machine reaches a top-level final state.

See also running.

[static] QScxmlStateMachine *QScxmlStateMachine::fromData(QIODevice *data, const QString &fileName = QString())

Creates a state machine by reading from the QIODevice specified by data.

This method will always return a state machine. If errors occur while reading the SCXML file, fileName, the state machine cannot be started. The errors can be retrieved by calling the parseErrors() method.

See also parseErrors().

[static] QScxmlStateMachine *QScxmlStateMachine::fromFile(const QString &fileName)

Creates a state machine from the SCXML file specified by fileName.

This method will always return a state machine. If errors occur while reading the SCXML file, the state machine cannot be started. The errors can be retrieved by calling the parseErrors() method.

See also parseErrors().

[slot] bool QScxmlStateMachine::init()

Initializes the state machine.

State machine initialization consists of calling QScxmlDataModel::setup(), setting the initial values for <data> elements, and executing any <script> tags of the <scxml> tag. The initial data values are taken from the initialValues property.

Returns false if parse errors occur or if any of the initialization steps fail. Returns true otherwise.

bool QScxmlStateMachine::isActive(const QString &scxmlStateName) const

Returns true if the state specified by scxmlStateName is active, false otherwise.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

[protected] bool QScxmlStateMachine::isActive(int stateIndex) const

Returns true if the state with the ID stateIndex is active.

This method is part of the interface to the compiled representation of SCXML state machines. It should only be used internally and by state machines compiled from SCXML documents.

bool QScxmlStateMachine::isDispatchableTarget(const QString &target) const

Returns true if a message to target can be dispatched by this state machine.

Valid targets are:

• #_parent for the parent state machine if the current state machine is started by <invoke>
• #_internal for the current state machine
• #_scxml_sessionid, where sessionid is the session ID of the current state machine
• #_servicename, where servicename is the ID or name of a service started with <invoke> by this state machine

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

bool QScxmlStateMachine::isRunning() const

Returns true if the state machine is running, false otherwise.

Note: Getter function for property running.

See also setRunning() and runningChanged().

[signal] void QScxmlStateMachine::log(const QString &label, const QString &msg)

This signal is emitted if a <log> tag is used in the SCXML. label is the value of the label attribute of the <log> tag. msg is the value of the evaluated expr attribute of the <log> tag. If there is no expr attribute, a null string will be returned.

[signal] void QScxmlStateMachine::reachedStableState()

This signal is emitted when the event queue is empty at the end of a macro step or when a final state is reached.

[signal] void QScxmlStateMachine::runningChanged(bool running)

This signal is emitted when the running property is changed with running as argument.

Note: Notifier signal for property running.

void QScxmlStateMachine::setDataModel(QScxmlDataModel *model)

Sets the data model for this state machine to model. There is a 1:1 relation between state machines and models. After setting the model once you cannot change it anymore. Any further attempts to set the model using this method will be ignored.

Note: Setter function for property dataModel.

See also dataModel().

void QScxmlStateMachine::setRunning(bool running)

Starts the state machine if running is true, or stops it otherwise.

Note: Setter function for property running.

See also start(), stop(), isRunning(), and runningChanged().

[slot] void QScxmlStateMachine::start()

Starts this state machine. The machine will reset its configuration and transition to the initial state. When a final top-level state is entered, the machine will emit the finished() signal.

Note: A state machine will not run without a running event loop, such as the main application event loop started with QCoreApplication::exec() or QApplication::exec().

See also runningChanged(), setRunning(), stop(), and finished().

QStringList QScxmlStateMachine::stateNames(bool compress = true) const

Retrieves a list of state names of all states.

When compress is true (the default), the states that contain child states will be filtered out and only the leaf states will be returned. When it is false, the full list of all states will be returned.

The returned list does not contain the states of possible nested state machines.

Note: The order of the state names in the list is the order in which the states occurred in the SCXML document.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

[slot] void QScxmlStateMachine::stop()

Stops this state machine. The machine will not execute any further state transitions. Its running property is set to false.

See also runningChanged(), start(), and setRunning().

void QScxmlStateMachine::submitEvent(const QString &eventName)

A utility method to create and submit an external event with the specified eventName as the name.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

void QScxmlStateMachine::submitEvent(const QString &eventName, const QVariant &data)

A utility method to create and submit an external event with the specified eventName as the name and data as the payload data.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.