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QMetaSequence::Iterable Class

class QMetaSequence::Iterable

The QMetaSequence::Iterable class is an iterable interface for a container in a QVariant. More...

This class was introduced in Qt 6.11.

Public Types

(since 6.11) class ConstIterator
(since 6.11) class Iterator
BidirectionalConstIterator
BidirectionalIterator
ForwardConstIterator
ForwardIterator
InputConstIterator
InputIterator
RandomAccessConstIterator
RandomAccessIterator

Public Functions

QVariant at(qsizetype idx) const
void setAt(qsizetype idx, const QVariant &value)

Detailed Description

This class allows several methods of accessing the values of a container held within a QVariant. An instance of QMetaSequence::Iterable can be extracted from a QVariant if it can be converted to a QVariantList, or if the container it contains is registered using Q_DECLARE_SEQUENTIAL_CONTAINER_METATYPE. Most sequential containers found in Qt and some found in the C++ standard library are automatically registered.

QList<int> intList = {7, 11, 42};

QVariant variant = QVariant::fromValue(intList);
if (variant.canConvert<QVariantList>()) {
    QMetaSequence::Iterable iterable = variant.value<QMetaSequence::Iterable>();
    // Can use C++11 range-for:
    for (const QVariant &v : iterable) {
        qDebug() << v;
    }
    // Can use iterators:
    QMetaSequence::Iterable::const_iterator it = iterable.begin();
    const QMetaSequence::Iterable::const_iterator end = iterable.end();
    for ( ; it != end; ++it) {
        qDebug() << *it;
    }
}

The container itself is not copied before iterating over it.

See also QVariant.

Member Type Documentation

[alias] Iterable::BidirectionalConstIterator

Exposes a const_iterator using std::bidirectional_iterator_tag.

[alias] Iterable::BidirectionalIterator

Exposes an iterator using std::bidirectional_iterator_tag.

[alias] Iterable::ForwardConstIterator

Exposes a const_iterator using std::forward_iterator_tag.

[alias] Iterable::ForwardIterator

Exposes an iterator using std::forward_iterator_tag.

[alias] Iterable::InputConstIterator

Exposes a const_iterator using std::input_iterator_tag.

[alias] Iterable::InputIterator

Exposes an iterator using std::input_iterator_tag.

[alias] Iterable::RandomAccessConstIterator

Exposes a const_iterator using std::random_access_iterator_tag.

[alias] Iterable::RandomAccessIterator

Exposes an iterator using std::random_access_iterator_tag.

Member Function Documentation

QVariant Iterable::at(qsizetype idx) const

Returns the value at position idx in the container.

Note: If the underlying container does not provide a native way to retrieve an element at an index, this method will synthesize the access using iterators. This behavior is deprecated and will be removed in a future version of Qt.

See also setAt().

void Iterable::setAt(qsizetype idx, const QVariant &value)

Sets the element at position idx in the container to value.

See also at().

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