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QSignalTransition Class Reference
[QtCore module]

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

 #include <QSignalTransition>

Inherits QAbstractTransition.

This class was introduced in Qt 4.6.

• List of all members, including inherited members

Properties

• senderObject : QObject *
• signal : QByteArray

• 3 properties inherited from QAbstractTransition
• 1 property inherited from QObject

Public Functions

• 9 public functions inherited from QAbstractTransition
• 29 public functions inherited from QObject

Reimplemented Protected Functions

• 3 protected functions inherited from QAbstractTransition
• 7 protected functions inherited from QObject

Additional Inherited Members

• 1 public slot inherited from QObject
• 1 signal inherited from QAbstractTransition
• 1 signal inherited from QObject
• 5 static public members inherited from QObject
• 3 protected functions inherited from QAbstractTransition
• 7 protected functions inherited from QObject

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) const {
         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:

signal : QByteArray

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

Access functions:

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().