QSignalTransition Class

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

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

• List of all members, including inherited members

Properties

• senderObject : QObject *
• signal : QByteArray

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

Public Functions

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

• 11 public functions inherited from QAbstractTransition
• 31 public functions inherited from QObject

Signals

void	senderObjectChanged()
void	signalChanged()

• 3 signals inherited from QAbstractTransition
• 2 signals inherited from QObject

Reimplemented Protected Functions

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

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

Additional Inherited Members

• 1 public slot inherited from QObject
• 11 static public members inherited from QObject
• 3 protected functions inherited from QAbstractTransition
• 9 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) {
        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);

Member Function Documentation

QSignalTransition::QSignalTransition(QState *sourceState = Q_NULLPTR)

Constructs a new signal transition with the given sourceState.

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

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.

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

Reimplemented from QObject::event().

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

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.

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

Reimplemented from QAbstractTransition::onTransition().

QObject *QSignalTransition::senderObject() const

Returns the sender object associated with this signal transition.

Note: Getter function for property senderObject.

See also setSenderObject().

[signal] void QSignalTransition::senderObjectChanged()

This signal is emitted when the senderObject property is changed.

This function was introduced in Qt 5.4.

Note: This is a private signal. It can be used in signal connections but cannot be emitted by the user.

Note: Notifier signal for property senderObject.

See also QSignalTransition::senderObject.

void QSignalTransition::setSenderObject(const QObject *sender)

Sets the sender object associated with this signal transition.

Note: Setter function for property senderObject.

See also senderObject().

void QSignalTransition::setSignal(const QByteArray &signal)

Sets the signal associated with this signal transition.

Note: Setter function for property signal.

See also signal().

QByteArray QSignalTransition::signal() const

Returns the signal associated with this signal transition.

Note: Getter function for property signal.

See also setSignal().

[signal] void QSignalTransition::signalChanged()

This signal is emitted when the signal property is changed.

This function was introduced in Qt 5.4.

Note: This is a private signal. It can be used in signal connections but cannot be emitted by the user.

Note: Notifier signal for property signal.

See also QSignalTransition::signal.