The QQmlListReference class allows the manipulation of QQmlListProperty properties. More...

#include <qqmllist.h>

Collaboration diagram for QQmlListReference:

Public Member Functions
	QQmlListReference ()
	Constructs an invalid instance.

	QQmlListReference (const QVariant &variant)

	QQmlListReference (QObject o, const char property)
	Constructs a QQmlListReference for object's property.

	QQmlListReference (const QQmlListReference &)

QQmlListReference &	operator= (const QQmlListReference &)

	~QQmlListReference ()

bool	isValid () const
	Returns true if the instance refers to a valid list property, otherwise false.

QObject *	object () const
	Returns the list property's object.

const QMetaObject *	listElementType () const
	Returns the QMetaObject for the elements stored in the list property, or \nullptr if the reference is invalid.

bool	canAppend () const
	Returns true if the list property can be appended to, otherwise false.

bool	canAt () const
	Returns true if the list property can queried by index, otherwise false.

bool	canClear () const
	Returns true if the list property can be cleared, otherwise false.

bool	canCount () const
	Returns true if the list property can be queried for its element count, otherwise false.

bool	canReplace () const
	Returns true if items in the list property can be replaced, otherwise false.

bool	canRemoveLast () const
	Returns true if the last item can be removed from the list property, otherwise false.

bool	isManipulable () const

bool	isReadable () const

bool	append (QObject *) const
	Appends object to the list.

QObject *	at (qsizetype) const
	Returns the list element at index, or 0 if the operation failed.

bool	clear () const
	Clears the list.

qsizetype	count () const
	Returns the number of objects in the list, or 0 if the operation failed.

qsizetype	size () const

bool	replace (qsizetype, QObject *) const
	Replaces the item at index in the list with object.

bool	removeLast () const
	Removes the last item in the list.

bool	operator== (const QQmlListReference &other) const
	Compares this QQmlListReference to other, and returns `true` if they are equal.

Friends
class	QQmlListReferencePrivate

Detailed Description

The QQmlListReference class allows the manipulation of QQmlListProperty properties.

Since: 5.0 \inmodule QtQml

QQmlListReference allows C++ programs to read from, and assign values to a QML list property in a simple and type-safe way. A QQmlListReference can be created by passing an object and property name or through a QQmlProperty instance. These two are equivalent:

QQmlListReference ref1(object, "children");
 
QQmlProperty ref2(object, "children");
QQmlListReference ref2 = qvariant_cast<QQmlListReference>(ref2.read());

Not all QML list properties support all operations. A set of methods, canAppend(), canAt(), canClear() and canCount() allow programs to query whether an operation is supported on a given property.

QML list properties are type-safe. Only QObject's that derive from the correct base class can be assigned to the list. The listElementType() method can be used to query the QMetaObject of the QObject type supported. Attempting to add objects of the incorrect type to a list property will fail.

Like with normal lists, when accessing a list element by index, it is the callers responsibility to ensure that it does not request an out of range element using the count() method before calling at().

Definition at line 182 of file qqmllist.h.

Constructor & Destructor Documentation

◆ QQmlListReference() [1/4]

QQmlListReference::QQmlListReference ( )

Constructs an invalid instance.

Definition at line 85 of file qqmllist.cpp.

◆ QQmlListReference() [2/4]

QQmlListReference::QQmlListReference ( const QVariant & variant )

explicit

Since: 6.1

Constructs a QQmlListReference from a QVariant variant containing a QQmlListProperty. If variant does not contain a list property, an invalid QQmlListReference is created. If the object owning the list property is destroyed after the reference is constructed, it will automatically become invalid. That is, it is safe to hold QQmlListReference instances even after the object is deleted.

Definition at line 132 of file qqmllist.cpp.

References QVariant::constData(), QMetaType::IsQmlList, QVariant::metaType(), QQmlListProperty< T >::object, QQmlListReferencePrivate::object, QQmlListReferencePrivate::property, QQmlListReferencePrivate::propertyType, QQmlListReferencePrivate, and variant.

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◆ QQmlListReference() [3/4]

QQmlListReference::QQmlListReference	(	QObject *	object,
		const char *	property )

Constructs a QQmlListReference for object's property.

If property is not a list property, an invalid QQmlListReference is created. If object is destroyed after the reference is constructed, it will automatically become invalid. That is, it is safe to hold QQmlListReference instances even after object is deleted.

Definition at line 154 of file qqmllist.cpp.

References args, QMetaObject::metacall(), object(), QQmlListReferencePrivate::object, QQmlListReferencePrivate::property, QQmlPropertyCache::property(), property, QQmlListReferencePrivate::propertyType, QQmlListReferencePrivate, and QMetaObject::ReadProperty.

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◆ QQmlListReference() [4/4]

QQmlListReference::QQmlListReference ( const QQmlListReference & o )

Definition at line 174 of file qqmllist.cpp.

References QQmlListReferencePrivate::addref().

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◆ ~QQmlListReference()

QQmlListReference::~QQmlListReference ( )

Definition at line 190 of file qqmllist.cpp.

References QQmlListReferencePrivate::release().

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Member Function Documentation

◆ append()

bool QQmlListReference::append ( QObject * object ) const

Appends object to the list.

Returns true if the operation succeeded, otherwise false.

See also: canAppend()

Definition at line 326 of file qqmllist.cpp.

References QQmlListProperty< T >::append, canAppend(), isObjectCompatible(), and QQmlListReferencePrivate::property.

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◆ at()

QObject * QQmlListReference::at ( qsizetype index ) const

Returns the list element at index, or 0 if the operation failed.

See also: canAt()

Definition at line 343 of file qqmllist.cpp.

References QQmlListProperty< T >::at, canAt(), and QQmlListReferencePrivate::property.

Referenced by QQmlListAccessor::at().

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◆ canAppend()

bool QQmlListReference::canAppend ( ) const

Returns true if the list property can be appended to, otherwise false.

Returns false if the reference is invalid.

See also: append()

Definition at line 230 of file qqmllist.cpp.

References QQmlListProperty< T >::append, isValid(), and QQmlListReferencePrivate::property.

Referenced by append().

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◆ canAt()

bool QQmlListReference::canAt ( ) const

Returns true if the list property can queried by index, otherwise false.

Returns false if the reference is invalid.

See also: at()

Definition at line 241 of file qqmllist.cpp.

References QQmlListProperty< T >::at, isValid(), and QQmlListReferencePrivate::property.

Referenced by at().

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◆ canClear()

bool QQmlListReference::canClear ( ) const

Returns true if the list property can be cleared, otherwise false.

Returns false if the reference is invalid.

See also: clear()

Definition at line 252 of file qqmllist.cpp.

References QQmlListProperty< T >::clear, isValid(), and QQmlListReferencePrivate::property.

Referenced by clear().

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◆ canCount()

bool QQmlListReference::canCount ( ) const

Returns true if the list property can be queried for its element count, otherwise false.

Returns false if the reference is invalid.

See also: count()

Definition at line 263 of file qqmllist.cpp.

References QQmlListProperty< T >::count, isValid(), and QQmlListReferencePrivate::property.

Referenced by count().

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◆ canRemoveLast()

bool QQmlListReference::canRemoveLast ( ) const

Returns true if the last item can be removed from the list property, otherwise false.

Returns false if the reference is invalid.

See also: removeLast()

Definition at line 285 of file qqmllist.cpp.

References isValid(), QQmlListReferencePrivate::property, and QQmlListProperty< T >::removeLast.

Referenced by removeLast().

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◆ canReplace()

bool QQmlListReference::canReplace ( ) const

Returns true if items in the list property can be replaced, otherwise false.

Returns false if the reference is invalid.

See also: replace()

Definition at line 274 of file qqmllist.cpp.

References isValid(), QQmlListReferencePrivate::property, and QQmlListProperty< T >::replace.

Referenced by replace().

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◆ clear()

bool QQmlListReference::clear ( ) const

Clears the list.

Returns true if the operation succeeded, otherwise false.

See also: canClear()

Definition at line 355 of file qqmllist.cpp.

References canClear(), QQmlListProperty< T >::clear, and QQmlListReferencePrivate::property.

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◆ count()

qsizetype QQmlListReference::count ( ) const

Returns the number of objects in the list, or 0 if the operation failed.

Definition at line 367 of file qqmllist.cpp.

References canCount(), QQmlListProperty< T >::count, and QQmlListReferencePrivate::property.

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◆ isManipulable()

bool QQmlListReference::isManipulable ( ) const

Return true if at(), count(), append(), and either clear() or removeLast()
are implemented, so you can manipulate the list.

Mind that replace() and removeLast() can be emulated by stashing all
items and rebuilding the list using clear() and append(). Therefore,
they are not required for the list to be manipulable. Furthermore,
clear() can be emulated using removeLast().

See also: isReadable(), at(), count(), append(), clear(), replace(), removeLast()

Definition at line 301 of file qqmllist.cpp.

References QQmlListProperty< T >::append, QQmlListProperty< T >::at, QQmlListProperty< T >::clear, QQmlListProperty< T >::count, isValid(), and QQmlListReferencePrivate::property.

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◆ isReadable()

bool QQmlListReference::isReadable ( ) const

Return true if at() and count() are implemented, so you can access the elements.

See also: isManipulable(), at(), count()

Definition at line 316 of file qqmllist.cpp.

References QQmlListProperty< T >::at, QQmlListProperty< T >::count, isValid(), and QQmlListReferencePrivate::property.

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◆ isValid()

bool QQmlListReference::isValid ( ) const

Returns true if the instance refers to a valid list property, otherwise false.

Definition at line 198 of file qqmllist.cpp.

References QQmlListReferencePrivate::object.

Referenced by canAppend(), canAt(), canClear(), canCount(), canRemoveLast(), canReplace(), isManipulable(), isReadable(), listElementType(), and object().

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◆ listElementType()

const QMetaObject * QQmlListReference::listElementType ( ) const

Returns the QMetaObject for the elements stored in the list property, or \nullptr if the reference is invalid.

The QMetaObject can be used ahead of time to determine whether a given instance can be added to a list. If you didn't pass an engine on construction this may return nullptr.

Definition at line 219 of file qqmllist.cpp.

References QQmlListReferencePrivate::elementType(), and isValid().

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◆ object()

QObject * QQmlListReference::object ( ) const

Returns the list property's object.

Returns \nullptr if the reference is invalid.

Definition at line 206 of file qqmllist.cpp.

References isValid(), and QQmlListReferencePrivate::object.

Referenced by QQmlListReference().

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◆ operator=()

QQmlListReference & QQmlListReference::operator= ( const QQmlListReference & o )

Definition at line 181 of file qqmllist.cpp.

References o, and QQmlListReferencePrivate::release().

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◆ operator==()

bool QQmlListReference::operator== ( const QQmlListReference & other ) const

inline

Compares this QQmlListReference to other, and returns true if they are equal.

The two are only considered equal if one was created from the other via copy assignment or copy construction.

Note: Independently created references to the same object are not considered to be equal.

Definition at line 223 of file qqmllist.h.

References d, and other().

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◆ removeLast()

bool QQmlListReference::removeLast ( ) const

Removes the last item in the list.

Returns true if the operation succeeded, otherwise false.

See also: canRemoveLast()

Definition at line 404 of file qqmllist.cpp.

References canRemoveLast(), QQmlListReferencePrivate::property, and QQmlListProperty< T >::removeLast.

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◆ replace()

bool QQmlListReference::replace	(	qsizetype	index,
		QObject *	object ) const

Replaces the item at index in the list with object.

Returns true if the operation succeeded, otherwise false.

See also: canReplace()

Definition at line 386 of file qqmllist.cpp.

References canReplace(), isObjectCompatible(), QQmlListReferencePrivate::property, and QQmlListProperty< T >::replace.

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◆ size()

qsizetype QQmlListReference::size ( ) const

inline

Since: 6.2 Returns the number of objects in the list, or 0 if the operation failed.

Definition at line 220 of file qqmllist.h.

Friends And Related Symbol Documentation

◆ QQmlListReferencePrivate

friend class QQmlListReferencePrivate

friend

Definition at line 226 of file qqmllist.h.

Referenced by QQmlListReference(), and QQmlListReference().

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

qtdeclarative/src/qml/qml/qqmllist.h (e84686415187455a7153d61ca82478053f13e3f9)
qtdeclarative/src/qml/qml/qqmllist.cpp (405bd4299819e39397cea0090a9442fd4b6ce911)

Public Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

◆ QQmlListReference() [1/4]

◆ QQmlListReference() [2/4]

◆ QQmlListReference() [3/4]

◆ QQmlListReference() [4/4]

◆ ~QQmlListReference()

Member Function Documentation

◆ append()

◆ at()

◆ canAppend()

◆ canAt()

◆ canClear()

◆ canCount()

◆ canRemoveLast()

◆ canReplace()

◆ clear()

◆ count()

◆ isManipulable()

◆ isReadable()

◆ isValid()

◆ listElementType()

◆ object()

◆ operator=()

◆ operator==()

◆ removeLast()

◆ replace()

◆ size()

Friends And Related Symbol Documentation

◆ QQmlListReferencePrivate