QSequentialIterable Class

The QSequentialIterable class is an iterable interface for a container in a QVariant. More...

Header: #include <QSequentialIterable>
qmake: QT += core
Since: Qt 5.2

This class was introduced in Qt 5.2.

Public Types

Public Functions

QVariant at(int idx) const
QSequentialIterable::const_iterator begin() const
bool canReverseIterate() const
QSequentialIterable::const_iterator end() const
int size() const

Detailed Description

This class allows several methods of accessing the elements of a container held within a QVariant. An instance of QSequentialIterable can be extracted from a QVariant if it can be converted to a QVariantList.


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

  QVariant variant = QVariant::fromValue(intList);
  if (variant.canConvert<QVariantList>()) {
      QSequentialIterable iterable = variant.value<QSequentialIterable>();
      // Can use foreach:
      foreach (const QVariant &v, iterable) {
          qDebug() << v;
      }
      // Can use C++11 range-for:
      for (const QVariant &v : iterable) {
          qDebug() << v;
      }
      // Can use iterators:
      QSequentialIterable::const_iterator it = iterable.begin();
      const QSequentialIterable::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 Function Documentation

QVariant QSequentialIterable::at(int idx) const

Returns the element at position idx in the container.

QSequentialIterable::const_iterator QSequentialIterable::begin() const

Returns a QSequentialIterable::const_iterator for the beginning of the container. This can be used in stl-style iteration.

See also end().

bool QSequentialIterable::canReverseIterate() const

Returns whether it is possible to iterate over the container in reverse. This corresponds to the std::bidirectional_iterator_tag iterator trait of the const_iterator of the container.

QSequentialIterable::const_iterator QSequentialIterable::end() const

Returns a QSequentialIterable::const_iterator for the end of the container. This can be used in stl-style iteration.

See also begin().

int QSequentialIterable::size() const

Returns the number of elements in the container.