QScxmlStateMachine Class▲
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Header: QScxmlStateMachine
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Since: Qt 5.7
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CMake:
find_package(Qt6 REQUIRED COMPONENTS Scxml)
target_link_libraries(mytarget PRIVATE Qt6::Scxml)
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qmake: QT += scxml
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Inherited By:
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Instantiated By: qml-qtscxml-scxmlstatemachine.xml
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Inherits: QObject
Detailed Description▲
QScxmlStateMachine is an implementation of the State Chart XML (SCXML).
All states that are defined in the SCXML file are accessible as properties of QScxmlStateMachine. These properties are boolean values and indicate whether the state is active or inactive.
The QScxmlStateMachine needs a QEventLoop to work correctly. The event loop is used to implement the delay attribute for events and to schedule the processing of a state machine when events are received from nested (or parent) state machines.
Property Documentation▲
[bindable] dataModel : QScxmlDataModel*▲
This property supports QProperty bindings.
This property holds the data model to be used for this state machine.
SCXML data models are described in SCXML Specification - 5 Data Model and Data Manipulation. For more information about supported data models, see SCXML Compliance.
Changing the data model when the state machine has been initialized is not specified in the SCXML standard and leads to undefined behavior.
See Also▲
See also QScxmlDataModel, QScxmlNullDataModel, QScxmlCppDataModel
[bindable] initialValues : QVariantMap▲
This property supports QProperty bindings.
This property holds the initial values to be used for setting up the data model.
See Also▲
See also QScxmlStateMachine::init(), QScxmlDataModel
[bindable read-only] initialized : bool▲
This property supports QProperty bindings.
This property holds whether the state machine has been initialized.
It is true if the state machine has been initialized, false otherwise.
See Also▲
See also QScxmlStateMachine::init(), QScxmlDataModel
[read-only] invoked : const bool▲
This property holds whether the state machine was invoked from an outer state machine.
true when the state machine was started as a service with the <invoke> element, false otherwise.
Access functions:
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bool isInvoked() const
[bindable read-only] invokedServices : QList<QScxmlInvokableService*>▲
This property supports QProperty bindings.
This property holds a list of SCXML services that were invoked from the main state machine (possibly recursively).
[bindable] loader : QScxmlCompiler::Loader*▲
This property supports QProperty bindings.
This property holds the loader that is currently used to resolve and load URIs for the state machine.
[read-only] name : const QString▲
This property holds the name of the state machine as set by the name attribute of the <scxml> tag.
Access functions:
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name() const
[read-only] parseErrors : const QList<QScxmlError>▲
This property holds the list of parse errors that occurred while creating a state machine from an SCXML file.
Access functions:
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<> parseErrors() const
running : bool▲
This property holds the running state of this state machine
Access functions:
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bool isRunning() const
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void setRunning(bool running)
Notifier signal:
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void runningChanged(bool running)
See Also▲
See also start()
[read-only] sessionId : const QString▲
This property holds the session ID of the current state machine.
The session ID is used for message routing between parent and child state machines. If a state machine is started by an <invoke> element, any event it sends will have the invokeid field set to the session ID. The state machine will use the origin of an event (which is set by the target or targetexpr attribute in a <send> element) to dispatch messages to the correct child state machine.
Access functions:
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sessionId() const
See Also▲
See also QScxmlEvent::invokeId()
[bindable] tableData : QScxmlTableData*▲
This property supports QProperty bindings.
This property holds the table data that is used when generating C++ from an SCXML file.
The class implementing the state machine will use this property to assign the generated table data. The state machine does not assume ownership of the table data.
Member Function Documentation▲
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.
void QScxmlStateMachine::cancelDelayedEvent(const QString &sendId)▲
Cancels a delayed event with the specified sendId.
QMetaObject::Connection QScxmlStateMachine::connectToEvent(const QString &scxmlEventSpec, const QObject *receiver, const char *method, Qt::ConnectionType type = Qt::AutoConnection)▲
Creates a connection of the specified type from the event specified by scxmlEventSpec to the method in the receiver object. The receiver's method may take a QScxmlEvent as a parameter. For example:
void mySlot(const QScxmlEvent &event);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::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.
typename std::enable_if<!QtPrivate::FunctionPointer<Functor>::IsPointerToMemberFunction && !std::is_same<const char *, Functor>::value, QMetaObject::Connection>::type QScxmlStateMachine::connectToEvent(const QString &scxmlEventSpec, Functor functor, Qt::ConnectionType type = Qt::AutoConnection)▲
Creates a connection of the given type from the event specified by scxmlEventSpec to functor.
The functor 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.
typename std::enable_if<!QtPrivate::FunctionPointer<Functor>::IsPointerToMemberFunction && !std::is_same<const char *, Functor>::value, QMetaObject::Connection>::type QScxmlStateMachine::connectToEvent(const QString &scxmlEventSpec, const QObject *context, Functor functor, Qt::ConnectionType type = Qt::AutoConnection)▲
Creates a connection of the given type from the event specified by scxmlEventSpec to functor using context as context.
The functor 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.
typename std::enable_if<!QtPrivate::FunctionPointer<Functor>::IsPointerToMemberFunction && !std::is_same<const char *, Functor>::value, QMetaObject::Connection>::type QScxmlStateMachine::connectToState(const QString &scxmlStateName, Functor functor, Qt::ConnectionType type = Qt::AutoConnection)▲
Creates a connection of the given type from the state specified by scxmlStateName to functor.
The functor 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.
typename std::enable_if<!QtPrivate::FunctionPointer<Functor>::IsPointerToMemberFunction && !std::is_same<const char *, Functor>::value, QMetaObject::Connection>::type QScxmlStateMachine::connectToState(const QString &scxmlStateName, const QObject *context, Functor functor, Qt::ConnectionType type = Qt::AutoConnection)▲
Creates a connection of the given type from the state specified by scxmlStateName to functor using context as context.
The functor 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.
Getter function for property dataModel.
See Also▲
See also setDataModel()
void QScxmlStateMachine::finished()▲
This signal is emitted when the state machine reaches a top-level final state.
See Also▲
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▲
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▲
See also parseErrors()
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.
[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:
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#_parent for the parent state machine if the current state machine is started by <invoke>
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#_internal for the current state machine
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#_scxml_sessionid, where sessionid is the session ID of the current state machine
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#_servicename, where servicename is the ID or name of a service started with <invoke> by this state machine
bool QScxmlStateMachine::isRunning() const▲
Returns true if the state machine is running, false otherwise.
Getter function for property running.
See Also▲
See also setRunning(), runningChanged()
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.
[static] std::function<void (bool)> QScxmlStateMachine::onEntry(const QObject *receiver, const char *method)▲
Returns a functor that accepts a boolean argument and calls the given method on receiver using QMetaObject::invokeMethod() if that argument is true and receiver has not been deleted, yet.
The given method must not accept any arguments. method is the plain method name, not enclosed in SIGNAL() or SLOT().
This is useful to wrap handlers for connectToState() that should only be executed when the state is entered.
[static] std::function<void (bool)> QScxmlStateMachine::onEntry(Functor functor)▲
Returns a functor that accepts a boolean argument and calls the given functor if that argument is true. The given functor must not accept any arguments.
This is useful to wrap handlers for connectToState() that should only be executed when the state is entered.
[static] std::function<void (bool)> QScxmlStateMachine::onEntry(const typename QtPrivate::FunctionPointer<PointerToMemberFunction>::Object *receiver, PointerToMemberFunction method)▲
Returns a functor that accepts a boolean argument and calls the given method on receiver if that argument is true and the receiver has not been deleted, yet. The given method must not accept any arguments.
This is useful to wrap handlers for connectToState() that should only be executed when the state is entered.
[static] std::function<void (bool)> QScxmlStateMachine::onExit(const QObject *receiver, const char *method)▲
Returns a functor that accepts a boolean argument and calls the given method on receiver using QMetaObject::invokeMethod() if that argument is false and receiver has not been deleted, yet.
The given method must not accept any arguments. method is the plain method name, not enclosed in SIGNAL(...) or SLOT(...).
This is useful to wrap handlers for connectToState() that should only be executed when the state is left.
[static] std::function<void (bool)> QScxmlStateMachine::onExit(Functor functor)▲
Returns a functor that accepts a boolean argument and calls the given functor if that argument is false. The given functor must not accept any arguments.
This is useful to wrap handlers for connectToState() that should only be executed when the state is left.
[static] std::function<void (bool)> QScxmlStateMachine::onExit(const typename QtPrivate::FunctionPointer<PointerToMemberFunction>::Object *receiver, PointerToMemberFunction method)▲
Returns a functor that accepts a boolean argument and calls the given method on receiver if that argument is false and the receiver has not been deleted, yet. The given method must not accept any arguments.
This is useful to wrap handlers for connectToState() that should only be executed when the state is left.
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.
void QScxmlStateMachine::runningChanged(bool running)▲
This signal is emitted when the running property is changed with running as argument.
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.
Setter function for property dataModel.
See Also▲
See also dataModel()
void QScxmlStateMachine::setRunning(bool running)▲
Starts the state machine if running is true, or stops it otherwise.
Setter function for property running.
See Also▲
See also start(), stop(), isRunning(), runningChanged()
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.
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▲
See also runningChanged(), setRunning(), stop(), 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.
The order of the state names in the list is the order in which the states occurred in the SCXML document.
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▲
See also runningChanged(), start(), setRunning()
void QScxmlStateMachine::submitEvent(QScxmlEvent *event)▲
Submits the SCXML event event to the internal or external event queue depending on the priority of the event.
When a delay is set, the event will be queued for delivery after the timeout has passed. The state machine takes ownership of event and deletes it after processing.
void QScxmlStateMachine::submitEvent(const QString &eventName)▲
A utility method to create and submit an external event with the specified eventName as the name.
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.