QSignalTransition

The QSignalTransition class provides a transition based on a Qt signal. More...

 #include <QSignalTransition>

Inherits: QAbstractTransition.

This class was introduced in Qt 4.6.

Properties

Public Functions

QSignalTransition ( QState * sourceState = 0 )
QSignalTransition ( QObject * sender, const char * signal, QState * sourceState = 0 )
~QSignalTransition ()
QObject * senderObject () const
void setSenderObject ( QObject * sender )
void setSignal ( const QByteArray & signal )
QByteArray signal () const

Reimplemented Protected Functions

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

Additional Inherited Members

Detailed Description

The QSignalTransition class provides a transition based on a Qt signal.

Typically you would use the overload of QState::addTransition() that takes a sender and signal as arguments, rather than creating QSignalTransition objects directly. QSignalTransition is part of The State Machine Framework.

You can subclass QSignalTransition and reimplement eventTest() to make a signal transition conditional; the event object passed to eventTest() will be a QStateMachine::SignalEvent object. Example:

 class CheckedTransition : public QSignalTransition
 {
 public:
     CheckedTransition(QCheckBox *check)
         : QSignalTransition(check, SIGNAL(stateChanged(int))) {}
 protected:
     bool eventTest(QEvent *e) {
         if (!QSignalTransition::eventTest(e))
             return false;
         QStateMachine::SignalEvent *se = static_cast<QStateMachine::SignalEvent*>(e);
         return (se->arguments().at(0).toInt() == Qt::Checked);
     }
 };

 ...

 QCheckBox *check = new QCheckBox();
 check->setTristate(true);

 QState *s1 = new QState();
 QState *s2 = new QState();
 CheckedTransition *t1 = new CheckedTransition(check);
 t1->setTargetState(s2);
 s1->addTransition(t1);

Property Documentation

senderObject : QObject *

This property holds the sender object that this signal transition is associated with.

Access functions:

QObject * senderObject () const
void setSenderObject ( QObject * sender )

signal : QByteArray

This property holds the signal that this signal transition is associated with.

Access functions:

QByteArray signal () const
void setSignal ( const QByteArray & signal )

Member Function Documentation

QSignalTransition::QSignalTransition ( QState * sourceState = 0 )

Constructs a new signal transition with the given sourceState.

QSignalTransition::QSignalTransition ( QObject * sender, const char * signal, QState * sourceState = 0 )

Constructs a new signal transition associated with the given signal of the given sender, and with the given sourceState.

QSignalTransition::~QSignalTransition ()

Destroys this signal transition.

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

Reimplemented from QObject::event().

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

Reimplemented from QAbstractTransition::eventTest().

The default implementation returns true if the event is a QStateMachine::SignalEvent object and the event's sender and signal index match this transition, and returns false otherwise.

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

Reimplemented from QAbstractTransition::onTransition().

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