QQmlListReference

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

Synopsis

Functions

• def __eq__ (other)

• def append (arg__1)

• def at (arg__1)

• def canAppend ()

• def canAt ()

• def canClear ()

• def canCount ()

• def canRemoveLast ()

• def canReplace ()

• def clear ()

• def count ()

• def isManipulable ()

• def isReadable ()

• def isValid ()

• def listElementType ()

• def object ()

• def removeLast ()

• def replace (arg__1, arg__2)

• def size ()

Detailed Description

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() .

class PySide6.QtQml.QQmlListReference

PySide6.QtQml.QQmlListReference(arg__1, property[, arg__3=None])

PySide6.QtQml.QQmlListReference(arg__1)

PySide6.QtQml.QQmlListReference(variant[, engine=None])

Parameters

• arg__3 – PySide6.QtQml.QQmlEngine

• engine – PySide6.QtQml.QQmlEngine

• property – str

• variant – object

• arg__1 – PySide6.QtCore.QObject

Constructs an invalid instance.

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.

The engine is required to look up the element type, which may be a dynamically created QML type. If it’s omitted, only pre-registered types are available. The element type is needed when inserting values into the list and when the value meta type is explicitly retrieved.

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.

The engine is required to look up the element type, which may be a dynamically created QML type. If it’s omitted, only pre-registered types are available. The element type is needed when inserting values into the list and when the value meta type is explicitly retrieved.

PySide6.QtQml.QQmlListReference.append(arg__1)

Parameters

arg__1 – PySide6.QtCore.QObject

Return type

bool

Appends object to the list. Returns true if the operation succeeded, otherwise false.

See also

canAppend()

PySide6.QtQml.QQmlListReference.at(arg__1)

Parameters

arg__1 – qsizetype

Return type

PySide6.QtCore.QObject

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

See also

canAt()

PySide6.QtQml.QQmlListReference.canAppend()

Return type

bool

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

See also

append()

PySide6.QtQml.QQmlListReference.canAt()

Return type

bool

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

See also

at()

PySide6.QtQml.QQmlListReference.canClear()

Return type

bool

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

See also

clear()

PySide6.QtQml.QQmlListReference.canCount()

Return type

bool

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()

PySide6.QtQml.QQmlListReference.canRemoveLast()

Return type

bool

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()

PySide6.QtQml.QQmlListReference.canReplace()

Return type

bool

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

See also

replace()

PySide6.QtQml.QQmlListReference.clear()

Return type

bool

Clears the list. Returns true if the operation succeeded, otherwise false.

See also

canClear()

PySide6.QtQml.QQmlListReference.count()

Return type

qsizetype

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

PySide6.QtQml.QQmlListReference.isManipulable()

Return type

bool

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()

PySide6.QtQml.QQmlListReference.isReadable()

Return type

bool

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

See also

isManipulable() at() count()

PySide6.QtQml.QQmlListReference.isValid()

Return type

bool

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

PySide6.QtQml.QQmlListReference.listElementType()

Return type

PySide6.QtCore.QMetaObject

Returns the QMetaObject for the elements stored in the list property, or None 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.

PySide6.QtQml.QQmlListReference.object()

Return type

PySide6.QtCore.QObject

Returns the list property’s object. Returns None if the reference is invalid.

PySide6.QtQml.QQmlListReference.__eq__(other)

Parameters

other – PySide6.QtQml.QQmlListReference

Return type

bool

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.

PySide6.QtQml.QQmlListReference.removeLast()

Return type

bool

Removes the last item in the list. Returns true if the operation succeeded, otherwise false.

See also

canRemoveLast()

PySide6.QtQml.QQmlListReference.replace(arg__1, arg__2)

Parameters

• arg__1 – qsizetype

• arg__2 – PySide6.QtCore.QObject

Return type

bool

Replaces the item at index in the list with object. Returns true if the operation succeeded, otherwise false.

See also

canReplace()

PySide6.QtQml.QQmlListReference.size()

Return type

qsizetype

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