QDeclarativeBinding Class Reference

#include <qdeclarativebinding_p.h>

Inheritance diagram for QDeclarativeBinding:

Public Types
enum	EvaluateFlag { RequiresThisObject = 0x01 }
typedef int	Identifier
Public Types inherited from QDeclarativeAbstractBinding
enum	DestroyMode { DisconnectBinding, KeepBindingConnected }
enum	DisconnectMode { DisconnectOne, DisconnectAll }
typedef QWeakPointer< QDeclarativeAbstractBinding >	Pointer
enum	Type { PropertyBinding, ValueTypeProxy }

Public Slots
void	update ()
Public Slots inherited from QObject
void	deleteLater ()
	Schedules this object for deletion. More...

Public Functions
virtual void	disconnect (DisconnectMode disconnectMode)
bool	enabled () const
EvaluateFlags	evaluateFlags () const
virtual QString	expression () const
QDeclarativeProperty	property () const
	QDeclarativeBinding (const QString &, QObject *, QDeclarativeContext *, QObject *parent=0)
	QDeclarativeBinding (const QString &, QObject *, QDeclarativeContextData *, QObject *parent=0)
	QDeclarativeBinding (void *, QDeclarativeRefCount *, QObject *, QDeclarativeContextData *, const QString &, int, QObject *parent)
	QDeclarativeBinding (const QScriptValue &, QObject *, QDeclarativeContextData *, QObject *parent=0)
virtual void	setEnabled (bool, QDeclarativePropertyPrivate::WriteFlags flags)
void	setEvaluateFlags (EvaluateFlags flags)
void	setTarget (const QDeclarativeProperty &)
virtual void	update (QDeclarativePropertyPrivate::WriteFlags flags)
Public Functions inherited from QDeclarativeExpression
void	clearError ()
	Clear any expression errors. More...
QDeclarativeContext *	context () const
	Returns the QDeclarativeContext this expression is associated with, or 0 if there is no association or the QDeclarativeContext has been destroyed. More...
QDeclarativeEngine *	engine () const
	Returns the QDeclarativeEngine this expression is associated with, or 0 if there is no association or the QDeclarativeEngine has been destroyed. More...
QDeclarativeError	error () const
	Return any error from the last call to evaluate(). More...
QVariant	evaluate (bool *valueIsUndefined=0)
	Evaulates the expression, returning the result of the evaluation, or an invalid QVariant if the expression is invalid or has an error. More...
QString	expression () const
	Returns the expression string. More...
bool	hasError () const
	Returns true if the last call to evaluate() resulted in an error, otherwise false. More...
int	lineNumber () const
	Returns the source file line number for this expression. More...
bool	notifyOnValueChanged () const
	Returns true if the valueChanged() signal is emitted when the expression's evaluated value changes. More...
	QDeclarativeExpression ()
	Create an invalid QDeclarativeExpression. More...
	QDeclarativeExpression (QDeclarativeContext *, QObject *, const QString &, QObject *=0)
	Create a QDeclarativeExpression object that is a child of parent. More...
QObject *	scopeObject () const
	Returns the expression's scope object, if provided, otherwise 0. More...
void	setExpression (const QString &)
	Set the expression to expression. More...
void	setNotifyOnValueChanged (bool)
	Sets whether the valueChanged() signal is emitted when the expression's evaluated value changes. More...
void	setSourceLocation (const QString &fileName, int line)
	Set the location of this expression to line of url. More...
QString	sourceFile () const
	Returns the source file URL for this expression. More...
virtual	~QDeclarativeExpression ()
	Destroy the QDeclarativeExpression instance. More...
Public Functions inherited from QObject
bool	blockSignals (bool b)
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). More...
const QObjectList &	children () const
	Returns a list of child objects. More...
bool	connect (const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const
bool	disconnect (const char *signal=0, const QObject *receiver=0, const char *member=0)
bool	disconnect (const QObject *receiver, const char *member=0)
void	dumpObjectInfo ()
	Dumps information about signal connections, etc. More...
void	dumpObjectTree ()
	Dumps a tree of children to the debug output. More...
QList< QByteArray >	dynamicPropertyNames () const
	Returns the names of all properties that were dynamically added to the object using setProperty(). More...
virtual bool	event (QEvent *)
	This virtual function receives events to an object and should return true if the event e was recognized and processed. More...
virtual bool	eventFilter (QObject *, QEvent *)
	Filters events if this object has been installed as an event filter for the watched object. More...
template<typename T >
T	findChild (const QString &aName=QString()) const
	Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. More...
template<typename T >
QList< T >	findChildren (const QString &aName=QString()) const
	Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. More...
template<typename T >
QList< T >	findChildren (const QRegExp &re) const
bool	inherits (const char *classname) const
	Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false. More...
void	installEventFilter (QObject *)
	Installs an event filter filterObj on this object. More...
bool	isWidgetType () const
	Returns true if the object is a widget; otherwise returns false. More...
void	killTimer (int id)
	Kills the timer with timer identifier, id. More...
virtual const QMetaObject *	metaObject () const
	Returns a pointer to the meta-object of this object. More...
void	moveToThread (QThread *thread)
	Changes the thread affinity for this object and its children. More...
QString	objectName () const
QObject *	parent () const
	Returns a pointer to the parent object. More...
QVariant	property (const char *name) const
	Returns the value of the object's name property. More...
Q_INVOKABLE	QObject (QObject *parent=0)
	Constructs an object with parent object parent. More...
void	removeEventFilter (QObject *)
	Removes an event filter object obj from this object. More...
void	setObjectName (const QString &name)
void	setParent (QObject *)
	Makes the object a child of parent. More...
bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value. More...
void	setUserData (uint id, QObjectUserData *data)
bool	signalsBlocked () const
	Returns true if signals are blocked; otherwise returns false. More...
int	startTimer (int interval)
	Starts a timer and returns a timer identifier, or returns zero if it could not start a timer. More...
QThread *	thread () const
	Returns the thread in which the object lives. More...
QObjectUserData *	userData (uint id) const
virtual	~QObject ()
	Destroys the object, deleting all its child objects. More...
Public Functions inherited from QDeclarativeAbstractBinding
void	addToObject (QObject *, int)
	Add this binding to object. More...
virtual Type	bindingType () const
virtual void	destroy (DestroyMode mode=DisconnectBinding)
	Destroy the binding. More...
QObject *	object () const
int	propertyIndex () const
	QDeclarativeAbstractBinding ()
void	removeFromObject ()
	Remove the binding from the object. More...
void	setEnabled (bool e)
void	update ()

Static Public Functions
static QDeclarativeBinding *	createBinding (Identifier, QObject *, QDeclarativeContext *, const QString &, int, QObject *parent=0)
Static Public Functions inherited from QObject
static bool	connect (const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType=Qt::AutoConnection)
	Creates a connection of the given type from the signal in the sender object to the method in the receiver object. More...
static bool	connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)
static bool	disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member)
	Disconnects signal in object sender from method in object receiver. More...
static bool	disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member)
static uint	registerUserData ()
static QString	tr (const char *sourceText, const char *comment=0, int n=-1)
static QString	trUtf8 (const char *sourceText, const char *comment=0, int n=-1)
Static Public Functions inherited from QDeclarativeAbstractBinding
static Pointer	getPointer (QDeclarativeAbstractBinding *p)

Static Public Variables
static Identifier	Invalid = -1
Static Public Variables inherited from QObject
static const QMetaObject	staticMetaObject
	This variable stores the meta-object for the class. More...

Protected Functions
void	emitValueChanged ()
	~QDeclarativeBinding ()
Protected Functions inherited from QDeclarativeExpression
	QDeclarativeExpression (QDeclarativeContextData *, QObject *, const QString &, QDeclarativeExpressionPrivate &dd)
	QDeclarativeExpression (QDeclarativeContextData *, QObject *, const QScriptValue &, QDeclarativeExpressionPrivate &dd)
	QDeclarativeExpression (QDeclarativeContextData *, void *, QDeclarativeRefCount *rc, QObject *me, const QString &, int, QDeclarativeExpressionPrivate &dd)
Protected Functions inherited from QObject
virtual void	childEvent (QChildEvent *)
	This event handler can be reimplemented in a subclass to receive child events. More...
virtual void	connectNotify (const char *signal)
	This virtual function is called when something has been connected to signal in this object. More...
virtual void	customEvent (QEvent *)
	This event handler can be reimplemented in a subclass to receive custom events. More...
virtual void	disconnectNotify (const char *signal)
	This virtual function is called when something has been disconnected from signal in this object. More...
	QObject (QObjectPrivate &dd, QObject *parent=0)
int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal. More...
QObject *	sender () const
	Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns 0. More...
int	senderSignalIndex () const
virtual void	timerEvent (QTimerEvent *)
	This event handler can be reimplemented in a subclass to receive timer events for the object. More...
Protected Functions inherited from QDeclarativeAbstractBinding
void	clear ()
virtual	~QDeclarativeAbstractBinding ()

Additional Inherited Members
Signals inherited from QDeclarativeExpression
void	valueChanged ()
	Emitted each time the expression value changes from the last time it was evaluated. More...
Signals inherited from QObject
void	destroyed (QObject *=0)
	This signal is emitted immediately before the object obj is destroyed, and can not be blocked. More...
Protected Variables inherited from QObject
QScopedPointer< QObjectData >	d_ptr
Static Protected Variables inherited from QObject
static const QMetaObject	staticQtMetaObject
Related Functions inherited from QObject
T	qFindChildqFindChildren (const QObject *obj, const QString &name)()
QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()
QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QRegExp &regExp)()
T *	qobject_cast (QObject *object)
	QObjectList
void *	qt_find_obj_child (QObject *parent, const char *type, const QString &name)
	Returns a pointer to the object named name that inherits type and with a given parent. More...

Detailed Description

Definition at line 176 of file qdeclarativebinding_p.h.

Typedefs

Identifier

typedef int QDeclarativeBinding::Identifier

Definition at line 203 of file qdeclarativebinding_p.h.

Enumerations

EvaluateFlag

enum QDeclarativeBinding::EvaluateFlag

Enumerator
RequiresThisObject

Definition at line 180 of file qdeclarativebinding_p.h.

{ RequiresThisObject = 0x01 };

Constructors and Destructors

QDeclarativeBinding() [1/4]

QDeclarativeBinding::QDeclarativeBinding	(	const QString &	str,
		QObject *	obj,
		QDeclarativeContext *	ctxt,
		QObject *	parent = 0
	)

Definition at line 267 of file qdeclarativebinding.cpp.

Referenced by createBinding().

: QDeclarativeExpression(QDeclarativeContextData::get(ctxt), obj, str, *new QDeclarativeBindingPrivate)
{
    setParent(parent);
    setNotifyOnValueChanged(true);
}

QDeclarativeBinding() [2/4]

QDeclarativeBinding::QDeclarativeBinding	(	const QString &	str,
		QObject *	obj,
		QDeclarativeContextData *	ctxt,
		QObject *	parent = 0
	)

Definition at line 275 of file qdeclarativebinding.cpp.

: QDeclarativeExpression(ctxt, obj, str, *new QDeclarativeBindingPrivate)
{
    setParent(parent);
    setNotifyOnValueChanged(true);
}

QDeclarativeBinding() [3/4]

QDeclarativeBinding::QDeclarativeBinding	(	void *	data,
		QDeclarativeRefCount *	rc,
		QObject *	obj,
		QDeclarativeContextData *	ctxt,
		const QString &	url,
		int	lineNumber,
		QObject *	parent
	)

Definition at line 233 of file qdeclarativebinding.cpp.

: QDeclarativeExpression(ctxt, data, rc, obj, url, lineNumber, *new QDeclarativeBindingPrivate)
{
    setParent(parent);
    setNotifyOnValueChanged(true);
}

QDeclarativeBinding() [4/4]

QDeclarativeBinding::QDeclarativeBinding	(	const QScriptValue &	func,
		QObject *	obj,
		QDeclarativeContextData *	ctxt,
		QObject *	parent = 0
	)

Definition at line 283 of file qdeclarativebinding.cpp.

: QDeclarativeExpression(ctxt, obj, func, *new QDeclarativeBindingPrivate)
{
    setParent(parent);
    setNotifyOnValueChanged(true);
}

~QDeclarativeBinding()

QDeclarativeBinding::~QDeclarativeBinding ( )

protected

Definition at line 290 of file qdeclarativebinding.cpp.

{
}

Functions

createBinding()

QDeclarativeBinding * QDeclarativeBinding::createBinding ( Identifier  id, QObject *  obj, QDeclarativeContext *  ctxt, const QString &  url, int  lineNumber, QObject *  parent = 0  )

static

Definition at line 243 of file qdeclarativebinding.cpp.

Referenced by QDeclarativePropertyChanges::actions().

{
    if (id < 0)
        return 0;

    Q_ASSERT(ctxt);
    QDeclarativeContextData *ctxtdata = QDeclarativeContextData::get(ctxt);

    QDeclarativeEnginePrivate *engine = QDeclarativeEnginePrivate::get(ctxtdata->engine);
    QDeclarativeCompiledData *cdata = 0;
    QDeclarativeTypeData *typeData = 0;
    if (!ctxtdata->url.isEmpty()) {
        typeData = engine->typeLoader.get(ctxtdata->url);
        cdata = typeData->compiledData();
    }
    QDeclarativeBinding *rv = cdata ? new QDeclarativeBinding((void*)cdata->datas.at(id).constData(), cdata, obj, ctxtdata, url, lineNumber, parent) : 0;
    if (cdata)
        cdata->release();
    if (typeData)
        typeData->release();
    return rv;
}

disconnect()

void QDeclarativeBinding::disconnect ( DisconnectMode  disconnectMode )

virtual

Implements QDeclarativeAbstractBinding.

Definition at line 494 of file qdeclarativebinding.cpp.

{
    Q_UNUSED(disconnectMode);
    setNotifyOnValueChanged(false);
}

emitValueChanged()

void QDeclarativeBinding::emitValueChanged ( )

protected

enabled()

bool QDeclarativeBinding::enabled

(

)

const

Definition at line 482 of file qdeclarativebinding.cpp.

{
    Q_D(const QDeclarativeBinding);

    return d->enabled;
}

evaluateFlags()

QDeclarativeBinding::EvaluateFlags QDeclarativeBinding::evaluateFlags

(

)

const

Definition at line 314 of file qdeclarativebinding.cpp.

Referenced by QDeclarativeValueTypeScriptClass::setProperty(), and QDeclarativeObjectScriptClass::setProperty().

{
    Q_D(const QDeclarativeBinding);
    return QDeclarativeBinding::EvaluateFlags(static_cast<int>(d->evaluateFlags()));
}

expression()

QString QDeclarativeBinding::expression ( ) const

virtual

Reimplemented from QDeclarativeAbstractBinding.

Definition at line 489 of file qdeclarativebinding.cpp.

Referenced by QDeclarativeBindingProfiler::QDeclarativeBindingProfiler(), QDeclarativeValueTypeScriptClass::setProperty(), QDeclarativeObjectScriptClass::setProperty(), and QDeclarativeStateGroupPrivate::updateAutoState().

{
    return QDeclarativeExpression::expression();
}

property()

QDeclarativeProperty QDeclarativeBinding::property

(

)

const

Definition at line 302 of file qdeclarativebinding.cpp.

Referenced by QDeclarativeParentChange::actions().

{
   Q_D(const QDeclarativeBinding);
   return d->property; 
}

setEnabled()

void QDeclarativeBinding::setEnabled ( bool  e, QDeclarativePropertyPrivate::WriteFlags  flags  )

virtual

Implements QDeclarativeAbstractBinding.

Definition at line 472 of file qdeclarativebinding.cpp.

{
    Q_D(QDeclarativeBinding);
    d->enabled = e;
    setNotifyOnValueChanged(e);

    if (e) 
        update(flags);
}

setEvaluateFlags()

void QDeclarativeBinding::setEvaluateFlags

(

EvaluateFlags

flags

)

Definition at line 308 of file qdeclarativebinding.cpp.

Referenced by QDeclarativeValueTypeScriptClass::setProperty(), and QDeclarativeObjectScriptClass::setProperty().

{
    Q_D(QDeclarativeBinding);
    d->setEvaluateFlags(QDeclarativeQtScriptExpression::EvaluateFlags(static_cast<int>(flags)));
}

setTarget()

void QDeclarativeBinding::setTarget

(

const QDeclarativeProperty &

prop

)

Definition at line 294 of file qdeclarativebinding.cpp.

Referenced by QDeclarativePropertyChanges::actions(), QDeclarativeParentChange::actions(), QDeclarativePropertyChanges::changeExpression(), QDeclarativeEngineDebugService::setBinding(), QDeclarativeValueTypeScriptClass::setProperty(), and QDeclarativeObjectScriptClass::setProperty().

{
    Q_D(QDeclarativeBinding);
    d->property = prop;

    update();
}

update() [1/2]

void QDeclarativeBinding::update ( QDeclarativePropertyPrivate::WriteFlags  flags )

virtual

Implements QDeclarativeAbstractBinding.

Definition at line 336 of file qdeclarativebinding.cpp.

Referenced by QDeclarativeEngineDebugService::setBinding().

{
    Q_D(QDeclarativeBinding);

    if (!d->enabled || !d->context() || !d->context()->isValid()) 
        return;

    if (!d->updating) {
        QDeclarativeBindingProfiler prof(this);
        d->updating = true;
        bool wasDeleted = false;
        d->deleted = &wasDeleted;

        if (d->property.propertyType() == qMetaTypeId<QDeclarativeBinding *>()) {

            int idx = d->property.index();
            Q_ASSERT(idx != -1);

            QDeclarativeBinding *t = this;
            int status = -1;
            void *a[] = { &t, 0, &status, &flags };
            QMetaObject::metacall(d->property.object(),
                                  QMetaObject::WriteProperty,
                                  idx, a);

            if (wasDeleted)
                return;

        } else {
            QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(d->context()->engine);

            bool isUndefined = false;
            QVariant value;

            QScriptValue scriptValue = d->scriptValue(0, &isUndefined);
            if (wasDeleted)
                return;

            if (d->property.propertyTypeCategory() == QDeclarativeProperty::List) {
                value = ep->scriptValueToVariant(scriptValue, qMetaTypeId<QList<QObject *> >());
            } else if (scriptValue.isNull() && 
                       d->property.propertyTypeCategory() == QDeclarativeProperty::Object) {
                value = QVariant::fromValue((QObject *)0);
            } else {
                value = ep->scriptValueToVariant(scriptValue, d->property.propertyType());
                if (value.userType() == QMetaType::QObjectStar && !qvariant_cast<QObject*>(value)) {
                    // If the object is null, we extract the predicted type.  While this isn't
                    // 100% reliable, in many cases it gives us better error messages if we
                    // assign this null-object to an incompatible property
                    int type = ep->objectClass->objectType(scriptValue);
                    QObject *o = 0;
                    value = QVariant(type, (void *)&o);
                }
            }


            if (d->error.isValid()) {

            } else if (isUndefined && d->property.isResettable()) {

                d->property.reset();

            } else if (isUndefined && d->property.propertyType() == qMetaTypeId<QVariant>()) {

                QDeclarativePropertyPrivate::write(d->property, QVariant(), flags);

            } else if (isUndefined) {

                QUrl url = QUrl(d->url);
                int line = d->line;
                if (url.isEmpty()) url = QUrl(QLatin1String("<Unknown File>"));

                d->error.setUrl(url);
                d->error.setLine(line);
                d->error.setColumn(-1);
                d->error.setDescription(QLatin1String("Unable to assign [undefined] to ") +
                                        QLatin1String(QMetaType::typeName(d->property.propertyType())) +
                                        QLatin1String(" ") + d->property.name());

            } else if (!scriptValue.isRegExp() && scriptValue.isFunction()) {

                QUrl url = QUrl(d->url);
                int line = d->line;
                if (url.isEmpty()) url = QUrl(QLatin1String("<Unknown File>"));

                d->error.setUrl(url);
                d->error.setLine(line);
                d->error.setColumn(-1);
                d->error.setDescription(QLatin1String("Unable to assign a function to a property."));

            } else if (d->property.object() &&
                       !QDeclarativePropertyPrivate::write(d->property, value, flags)) {

                if (wasDeleted)
                    return;

                QUrl url = QUrl(d->url);
                int line = d->line;
                if (url.isEmpty()) url = QUrl(QLatin1String("<Unknown File>"));

                const char *valueType = 0;
                if (value.userType() == QVariant::Invalid) valueType = "null";
                else valueType = QMetaType::typeName(value.userType());

                d->error.setUrl(url);
                d->error.setLine(line);
                d->error.setColumn(-1);
                d->error.setDescription(QLatin1String("Unable to assign ") +
                                        QLatin1String(valueType) +
                                        QLatin1String(" to ") +
                                        QLatin1String(QMetaType::typeName(d->property.propertyType())));
            }

            if (wasDeleted)
                return;

            if (d->error.isValid()) {
               if (!d->addError(ep)) ep->warning(this->error());
            } else {
                d->removeError();
            }
        }

        d->updating = false;
        d->deleted = 0;
    } else {
        qmlInfo(d->property.object()) << tr("Binding loop detected for property \"%1\"").arg(d->property.name());
    }
}

update [2/2]

void QDeclarativeBinding::update ( )

inlineslot

Definition at line 208 of file qdeclarativebinding_p.h.

Referenced by setEnabled(), setTarget(), and update().

{ update(QDeclarativePropertyPrivate::DontRemoveBinding); }

Properties

Invalid

QDeclarativeBinding::Identifier QDeclarativeBinding::Invalid = -1

static

Definition at line 204 of file qdeclarativebinding_p.h.

Referenced by QDeclarativePropertyChanges::actions(), QDeclarativePropertyChanges::changeExpression(), QDeclarativePropertyChangesPrivate::decode(), and QDeclarativeAbstractBinding::setEnabled().

---

The documentation for this class was generated from the following files:

• /src/declarative/qml/qdeclarativebinding_p.h
• /src/declarative/qml/qdeclarativebinding.cpp