QEventTransition Class

The QEventTransition class provides a QObject-specific transition for Qt events. More...

Header: #include <QEventTransition>
qmake: QT += core
Since: Qt 4.6
Inherits: QAbstractTransition

This class was introduced in Qt 4.6.

Properties

Public Functions

QEventTransition(QObject *object, QEvent::Type type, QState *sourceState = nullptr)
QEventTransition(QState *sourceState = nullptr)
virtual ~QEventTransition()
QObject *eventSource() const
QEvent::Type eventType() const
void setEventSource(QObject *object)
void setEventType(QEvent::Type type)

Reimplemented Protected Functions

virtual bool event(QEvent *e) override
virtual bool eventTest(QEvent *event) override
virtual void onTransition(QEvent *event) override

Detailed Description

A QEventTransition object binds an event to a particular QObject. QEventTransition is part of The State Machine Framework.

Example:


  QPushButton *button = ...;
  QState *s1 = ...;
  QState *s2 = ...;
  // If in s1 and the button receives an Enter event, transition to s2
  QEventTransition *enterTransition = new QEventTransition(button, QEvent::Enter);
  enterTransition->setTargetState(s2);
  s1->addTransition(enterTransition);
  // If in s2 and the button receives an Exit event, transition back to s1
  QEventTransition *leaveTransition = new QEventTransition(button, QEvent::Leave);
  leaveTransition->setTargetState(s1);
  s2->addTransition(leaveTransition);

Subclassing

When reimplementing the eventTest() function, you should first call the base implementation to verify that the event is a QStateMachine::WrappedEvent for the proper object and event type. You may then cast the event to a QStateMachine::WrappedEvent and get the original event by calling QStateMachine::WrappedEvent::event(), and perform additional checks on that object.

See also QState::addTransition().

Property Documentation

eventSource : QObject*

This property holds the event source that this event transition is associated with

Access functions:

QObject *eventSource() const
void setEventSource(QObject *object)

eventType : QEvent::Type

This property holds the type of event that this event transition is associated with

Access functions:

QEvent::Type eventType() const
void setEventType(QEvent::Type type)

Member Function Documentation

QEventTransition::QEventTransition(QObject *object, QEvent::Type type, QState *sourceState = nullptr)

Constructs a new QEventTransition object associated with events of the given type for the given object, and with the given sourceState.

QEventTransition::QEventTransition(QState *sourceState = nullptr)

Constructs a new QEventTransition object with the given sourceState.

[virtual] QEventTransition::~QEventTransition()

Destroys this QObject event transition.

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

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

QObject *QEventTransition::eventSource() const

Returns the event source associated with this event transition.

Note: Getter function for property eventSource.

See also setEventSource().

[override virtual protected] bool QEventTransition::eventTest(QEvent *event)

Reimplements: QAbstractTransition::eventTest(QEvent *event).

QEvent::Type QEventTransition::eventType() const

Returns the event type that this event transition is associated with.

Note: Getter function for property eventType.

See also setEventType().

[override virtual protected] void QEventTransition::onTransition(QEvent *event)

Reimplements: QAbstractTransition::onTransition(QEvent *event).

void QEventTransition::setEventSource(QObject *object)

Sets the event source associated with this event transition to be the given object.

Note: Setter function for property eventSource.

See also eventSource().

void QEventTransition::setEventType(QEvent::Type type)

Sets the event type that this event transition is associated with.

Note: Setter function for property eventType.

See also eventType().