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

Properties

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

Signals

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(const QObject *sender)

Notifier signal:

void senderObjectChanged()[see note below]

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

signal : QByteArray

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

Access functions:

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

Notifier signal:

void signalChanged()[see note below]

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

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.