qitemselectionmodel.cpp

奇趣公司比较新的qt/emd版本

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#include "qitemselectionmodel.h"
#include <private/qitemselectionmodel_p.h>
#include <qdebug.h>

#ifndef QT_NO_ITEMVIEWS
/*!
    \class QItemSelectionRange

    \brief The QItemSelectionRange class manages information about a
    range of selected items in a model.

    \ingroup model-view

    A QItemSelectionRange contains information about a range of
    selected items in a model. A range of items is a contiguous array
    of model items, extending to cover a number of adjacent rows and
    columns with a common parent item; this can be visualized as a
    two-dimensional block of cells in a table. A selection range has a
    top(), left() a bottom(), right() and a parent().

    The QItemSelectionRange class is one of the \l{Model/View Classes}
    and is part of Qt's \l{Model/View Programming}{model/view framework}.

    The model items contained in the selection range can be obtained
    by using the items() function. Use
    QItemSelectionModel::selectedIndexes() to get a list of all
    selected items for a view.

    You can determine whether a given model item lies within a
    particular range by using the contains() function. Ranges can also
    be compared using the overloaded operators for equality and
    inequality, and the intersects() function allows you to determine
    whether two ranges overlap.

    \sa {Model/View Programming}, QAbstractItemModel, QItemSelection,
        QItemSelectionModel
*/

/*!
    \fn QItemSelectionRange::QItemSelectionRange()

    Constructs an empty selection range.
*/

/*!
    \fn QItemSelectionRange::QItemSelectionRange(const QItemSelectionRange &other)

    Copy constructor. Constructs a new selection range with the same contents
    as the \a other range given.

*/

/*!
    \fn QItemSelectionRange::QItemSelectionRange(const QModelIndex &topLeft, const QModelIndex &bottomRight)

    Constructs a new selection range containing only the index specified
    by the \a topLeft and the index \a bottomRight.

*/

/*!
    \fn QItemSelectionRange::QItemSelectionRange(const QModelIndex &index)

    Constructs a new selection range containing only the model item specified
    by the model index \a index.
*/

/*!
    \fn int QItemSelectionRange::top() const

    Returns the row index corresponding to the uppermost selected row in the
    selection range.

*/

/*!
    \fn int QItemSelectionRange::left() const

    Returns the column index corresponding to the leftmost selected column in the
    selection range.
*/

/*!
    \fn int QItemSelectionRange::bottom() const

    Returns the row index corresponding to the lowermost selected row in the
    selection range.

*/

/*!
    \fn int QItemSelectionRange::right() const

    Returns the column index corresponding to the rightmost selected column in
    the selection range.

*/

/*!
    \fn int QItemSelectionRange::width() const

    Returns the number of selected columns in the selection range.

*/

/*!
    \fn int QItemSelectionRange::height() const

    Returns the number of selected rows in the selection range.

*/

/*!
    \fn const QAbstractItemModel *QItemSelectionRange::model() const

    Returns the model that the items in the selection range belong to.
*/

/*!
    \fn QModelIndex QItemSelectionRange::topLeft() const

    Returns the index for the item located at the top-left corner of
    the selection range.

    \sa top(), left(), bottomRight()
*/

/*!
    \fn QModelIndex QItemSelectionRange::bottomRight() const

    Returns the index for the item located at the bottom-right corner
    of the selection range.

    \sa bottom(), right(), topLeft()
*/

/*!
    \fn QModelIndex QItemSelectionRange::parent() const

    Returns the parent model item index of the items in the selection range.

*/

/*!
    \fn bool QItemSelectionRange::contains(const QModelIndex &index) const

    Returns true if the model item specified by the \a index lies within the
    range of selected items; otherwise returns false.
*/

/*!
    \fn bool QItemSelectionRange::contains(int row, int column,
                                           const QModelIndex &parentIndex) const
    \overload

    Returns true if the model item specified by (\a row, \a column)
    and with \a parentIndex as the parent item lies within the range
    of selected items; otherwise returns false.
*/

/*!
    \fn bool QItemSelectionRange::intersects(const QItemSelectionRange &other) const

    Returns true if this selection range intersects (overlaps with) the \a other
    range given; otherwise returns false.

*/
bool QItemSelectionRange::intersects(const QItemSelectionRange &other) const
{
    return (isValid() && other.isValid()
            && parent() == other.parent()
            && ((top() <= other.top() && bottom() >= other.top())
                || (top() >= other.top() && top() <= other.bottom()))
            && ((left() <= other.left() && right() >= other.left())
                || (left() >= other.left() && left() <= other.right())));
}

/*!
    \fn QItemSelectionRange QItemSelectionRange::intersect(const QItemSelectionRange &other) const
    \obsolete

    Use intersected(\a other) instead.
*/

/*!
    \fn QItemSelectionRange QItemSelectionRange::intersected(const QItemSelectionRange &other) const
    \since 4.2

    Returns a new selection range containing only the items that are found in
    both the selection range and the \a other selection range.
*/

QItemSelectionRange QItemSelectionRange::intersect(const QItemSelectionRange &other) const
{
    if (model() == other.model() && parent() == other.parent()) {
        QModelIndex topLeft = model()->index(qMax(top(), other.top()),
                                             qMax(left(), other.left()),
                                             other.parent());
        QModelIndex bottomRight = model()->index(qMin(bottom(), other.bottom()),
                                                 qMin(right(), other.right()),
                                                 other.parent());
        return QItemSelectionRange(topLeft, bottomRight);
    }
    return QItemSelectionRange();
}

/*!
    \fn bool QItemSelectionRange::operator==(const QItemSelectionRange &other) const

    Returns true if the selection range is exactly the same as the \a other
    range given; otherwise returns false.

*/

/*!
    \fn bool QItemSelectionRange::operator!=(const QItemSelectionRange &other) const

    Returns true if the selection range differs from the \a other range given;
    otherwise returns false.

*/

/*!
    \fn bool QItemSelectionRange::isValid() const

    Returns true if the selection range is valid; otherwise returns false.

*/

/*!
    Returns the list of model index items stored in the selection.
*/

QModelIndexList QItemSelectionRange::indexes() const
{
    QModelIndex index;
    QModelIndexList result;
    if (isValid()) {
        for (int column = left(); column <= right(); ++column) {
            for (int row = top(); row <= bottom(); ++row) {
                index = model()->index(row, column, parent());
                if (model()->flags(index) & Qt::ItemIsSelectable)
                    result.append(index);
            }
        }
    }
    return result;
}

/*!
  \class QItemSelection

  \brief The QItemSelection class manages information about selected items in a model.

  \ingroup model-view

  A QItemSelection describes the items in a model that have been
  selected by the user. A QItemSelection is basically a list of
  selection ranges, see QItemSelectionRange. It provides functions for
  creating and manipulating selections, and selecting a range of items
  from a model.

  The QItemSelection class is one of the \l{Model/View Classes}
  and is part of Qt's \l{Model/View Programming}{model/view framework}.

  An item selection can be constructed and initialized to contain a
  range of items from an existing model. The following example constructs
  a selection that contains a range of items from the given \c model,
  beginning at the \c topLeft, and ending at the \c bottomRight.

  \code
    QItemSelection *selection = new QItemSelection(topLeft, bottomRight);
  \endcode

  An empty item selection can be constructed, and later populated as
  required. So, if the model is going to be unavailable when we construct
  the item selection, we can rewrite the above code in the following way:

  \code
    QItemSelection *selection = new QItemSelection();
    ...
    selection->select(topLeft, bottomRight);
  \endcode

  QItemSelection saves memory, and avoids unnecessary work, by working with
  selection ranges rather than recording the model item index for each
  item in the selection. Generally, an instance of this class will contain
  a list of non-overlapping selection ranges.

  Use merge() to merge one item selection into another without making
  overlapping ranges. Use split() to split one selection range into
  smaller ranges based on a another selection range.

  \sa {Model/View Programming}, QItemSelectionModel

*/

/*!
    \fn QItemSelection::QItemSelection()

    Constructs an empty selection.
*/

/*!
    Constructs an item selection that extends from the top-left model item,
    specified by the \a topLeft index, to the bottom-right item, specified
    by \a bottomRight.
*/
QItemSelection::QItemSelection(const QModelIndex &topLeft, const QModelIndex &bottomRight)
{
    select(topLeft, bottomRight);
}

/*!
    Adds the items in the range that extends from the top-left model
    item, specified by the \a topLeft index, to the bottom-right item,
    specified by \a bottomRight to the list.
*/
void QItemSelection::select(const QModelIndex &topLeft, const QModelIndex &bottomRight)
{
    if (!topLeft.isValid() || !bottomRight.isValid())
        return;

    if ((topLeft.model() != bottomRight.model())
        || topLeft.parent() != bottomRight.parent()) {
        qWarning("Can't select indexes from different model or with different parents");
        return;
    }
    if (topLeft.row() > bottomRight.row() || topLeft.column() > bottomRight.column()) {
        int top = qMin(topLeft.row(), bottomRight.row());
        int bottom = qMax(topLeft.row(), bottomRight.row());
        int left = qMin(topLeft.column(), bottomRight.column());
        int right = qMax(topLeft.column(), bottomRight.column());
        QModelIndex tl = topLeft.sibling(top, left);