qstandarditemmodel.cpp

奇趣公司比较新的qt/emd版本

    QStandardItemModel implements the QAbstractItemModel interface, which
    means that the model can be used to provide data in any view that supports
    that interface (such as QListView, QTableView and QTreeView, and your own
    custom views). For performance and flexibility, you may want to subclass
    QAbstractItemModel to provide support for different kinds of data
    repositories. For example, the QDirModel provides a model interface to the
    underlying file system, and does not actually store file information
    internally.

    When you want a list or tree, you typically create an empty
    QStandardItemModel and use appendRow() to add items to the model, and
    item() to access an item.  If your model represents a table, you typically
    pass the dimensions of the table to the QStandardItemModel constructor and
    use setItem() to position items into the table. You can also use setRowCount()
    and setColumnCount() to alter the dimensions of the model. To insert items,
    use insertRow() or insertColumn(), and to remove items, use removeRow() or
    removeColumn().

    You can set the header labels of your model with setHorizontalHeaderLabels()
    and setVerticalHeaderLabels().

    You can search for items in the model with findItems(), and sort the model by
    calling sort().

    Call clear() to remove all items from the model.

    An example usage of QStandardItemModel to create a table:

    \code
            QStandardItemModel model(4, 4);
            for (int row = 0; row < 4; ++row) {
                for (int column = 0; column < 4; ++column) {
                    QStandardItem *item = new QStandardItem(QString("row %0, column %1").arg(row).arg(column));
                    model.setItem(row, column, item);
                }
            }
    \endcode

    An example usage of QStandardItemModel to create a tree:

    \code
            QStandardItemModel model;
            QStandardItem *parentItem = model.invisibleRootItem();
            for (int i = 0; i < 4; ++i) {
                QStandardItem *item = new QStandardItem(QString("item %0").arg(i));
                parentItem->appendRow(item);
                parentItem = item;
            }
    \endcode

    After setting the model on a view, you typically want to react to user
    actions, such as an item being clicked. Since a QAbstractItemView provides
    QModelIndex-based signals and functions, you need a way to obtain the
    QStandardItem that corresponds to a given QModelIndex, and vice
    versa. itemFromIndex() and indexFromItem() provide this mapping. Typical
    usage of itemFromIndex() includes obtaining the item at the current index
    in a view, and obtaining the item that corresponds to an index carried by
    a QAbstractItemView signal, such as QAbstractItemView::clicked(). First
    you connect the view's signal to a slot in your class:

    \code
        QTreeView *treeView = new QTreeView(this);
        treeView->setModel(myStandardItemModel);
        connect(treeView, SIGNAL(clicked(QModelIndex)),
                this, SLOT(clicked(QModelIndex)));
    \endcode

    When you receive the signal, you call itemFromIndex() on the given model
    index to get a pointer to the item:

    \code
        void MyWidget::clicked(const QModelIndex &index)
        {
            QStandardItem *item = myStandardItemModel->itemFromIndex(index);
            // Do stuff with the item ...
        }
    \endcode

    Conversely, you must obtain the QModelIndex of an item when you want to
    invoke a model/view function that takes an index as argument. You can
    obtain the index either by using the model's indexFromItem() function, or,
    equivalently, by calling QStandardItem::index():

    \code
        treeView->scrollTo(item->index());
    \endcode

    You are, of course, not required to use the item-based approach; you could
    instead rely entirely on the QAbstractItemModel interface when working with
    the model, or use a combination of the two as appropriate.

    \sa QStandardItem, {Model/View Programming}, QAbstractItemModel,
    {itemviews/simpletreemodel}{Simple Tree Model example},
    {Item View Convenience Classes}
*/

/*!
    \fn void QStandardItemModel::itemChanged(QStandardItem *item)
    \since 4.2

    This signal is emitted whenever the data of \a item has changed.
*/

/*!
    Constructs a new item model with the given \a parent.
*/
QStandardItemModel::QStandardItemModel(QObject *parent)
    : QAbstractItemModel(*new QStandardItemModelPrivate, parent)
{
    Q_D(QStandardItemModel);
    d->init();
    d->root->d_func()->setModel(this);
}

/*!
    Constructs a new item model that initially has \a rows rows and \a columns
    columns, and that has the given \a parent.
*/
QStandardItemModel::QStandardItemModel(int rows, int columns, QObject *parent)
    : QAbstractItemModel(*new QStandardItemModelPrivate, parent)
{
    Q_D(QStandardItemModel);
    d->init();
    d->root->insertColumns(0, columns);
    d->columnHeaderItems.insert(0, columns, 0);
    d->root->insertRows(0, rows);
    d->rowHeaderItems.insert(0, rows, 0);
    d->root->d_func()->setModel(this);
}

/*!
  \internal
*/
QStandardItemModel::QStandardItemModel(QStandardItemModelPrivate &dd, QObject *parent)
    : QAbstractItemModel(dd, parent)
{
    Q_D(QStandardItemModel);
    d->init();
}

/*!
    Destructs the model. The model destroys all its items.
*/
QStandardItemModel::~QStandardItemModel()
{
}

/*!
    Removes all items (including header items) from the model and sets the
    number of rows and columns to zero.

    \sa removeColumns(), removeRows()
*/
void QStandardItemModel::clear()
{
    Q_D(QStandardItemModel);
    delete d->root;
    d->root = new QStandardItem;
    d->root->d_func()->setModel(this);
    qDeleteAll(d->columnHeaderItems);
    d->columnHeaderItems.clear();
    qDeleteAll(d->rowHeaderItems);
    d->rowHeaderItems.clear();
    reset();
}

/*!
    \since 4.2

    Returns a pointer to the QStandardItem associated with the given \a index.

    Calling this function is typically the initial step when processing
    QModelIndex-based signals from a view, such as
    QAbstractItemView::activated(). In your slot, you call itemFromIndex(),
    with the QModelIndex carried by the signal as argument, to obtain a
    pointer to the corresponding QStandardItem.

    Note that this function will lazily create an item for the index (using
    itemPrototype()), and set it in the parent item's child table, if no item
    already exists at that index.

    If \a index is an invalid index, this function returns 0.

    \sa indexFromItem()
*/
QStandardItem *QStandardItemModel::itemFromIndex(const QModelIndex &index) const
{
    Q_D(const QStandardItemModel);
    if ((index.row() < 0) || (index.column() < 0) || (index.model() != this))
        return 0;
    QStandardItem *parent = static_cast<QStandardItem*>(index.internalPointer());
    if (parent == 0)
        return 0;
    QStandardItem *item = parent->child(index.row(), index.column());
    // lazy part
    if (item == 0) {
        item = d->createItem();
        parent->d_func()->setChild(index.row(), index.column(), item);
    }
    return item;
}

/*!
    \since 4.2

    Returns the QModelIndex associated with the given \a item.

    Use this function when you want to perform an operation that requires the
    QModelIndex of the item, such as
    QAbstractItemView::scrollTo(). QStandardItem::index() is provided as
    convenience; it is equivalent to calling this function.

    \sa itemFromIndex(), QStandardItem::index()
*/
QModelIndex QStandardItemModel::indexFromItem(const QStandardItem *item) const
{
    if (item && item->d_func()->parent) {
        QPair<int, int> pos = item->d_func()->position();
        return createIndex(pos.first, pos.second, item->d_func()->parent);
    }
    return QModelIndex();
}

/*!
    \since 4.2

    Sets the number of rows in this model to \a rows. If
    this is less than rowCount(), the data in the unwanted rows
    is discarded.

    \sa setColumnCount()
*/
void QStandardItemModel::setRowCount(int rows)
{
    Q_D(QStandardItemModel);
    d->root->setRowCount(rows);
}

/*!
    \since 4.2

    Sets the number of columns in this model to \a columns. If
    this is less than columnCount(), the data in the unwanted columns
    is discarded.

    \sa setRowCount()
*/
void QStandardItemModel::setColumnCount(int columns)
{
    Q_D(QStandardItemModel);
    d->root->setColumnCount(columns);
}

/*!
    \since 4.2

    Sets the item for the given \a row and \a column to \a item. The model
    takes ownership of the item. If necessary, the row count and column count
    are increased to fit the item. The previous item at the given location (if
    there was one) is deleted.

    \sa item()
*/
void QStandardItemModel::setItem(int row, int column, QStandardItem *item)
{
    Q_D(QStandardItemModel);
    d->root->d_func()->setChild(row, column, item, true);
}

/*!
  \fn QStandardItemModel::setItem(int row, QStandardItem *item)
  \overload
*/

/*!
    \since 4.2

    Returns the item for the given \a row and \a column if one has been set;
    otherwise returns 0.

    \sa setItem(), takeItem(), itemFromIndex()
*/
QStandardItem *QStandardItemModel::item(int row, int column) const
{
    Q_D(const QStandardItemModel);
    return d->root->child(row, column);
}

/*!
    \since 4.2

    Returns the model's invisible root item.

    The invisible root item provides access to the model's top-level items
    through the QStandardItem API, making it possible to write functions that
    can treat top-level items and their children in a uniform way; for
    example, recursive functions involving a tree model.
*/
QStandardItem *QStandardItemModel::invisibleRootItem() const
{
    Q_D(const QStandardItemModel);
    return d->root;
}

/*!
    \since 4.2

    Sets the horizontal header item for \a column to \a item.  The model takes
    ownership of the item. If necessary, the column count is increased to fit
    the item. The previous header item (if there was one) is deleted.

    \sa horizontalHeaderItem(), setHorizontalHeaderLabels(),
    setVerticalHeaderItem()
*/
void QStandardItemModel::setHorizontalHeaderItem(int column, QStandardItem *item)
{
    Q_D(QStandardItemModel);
    if (column < 0)
        return;
    if (columnCount() <= column)
        setColumnCount(column + 1);

    QStandardItem *oldItem = d->columnHeaderItems.at(column);
    if (item == oldItem)
        return;

    if (item) {
        if (item->model() == 0) {
            item->d_func()->setModel(this);
        } else {
            qWarning("QStandardItem::setHorizontalHeaderItem: Ignoring duplicate insertion of item %p",
                     item);
            return;
        }
    }

    if (oldItem)
        oldItem->d_func()->setModel(0);
    delete oldItem;

    d->columnHeaderItems.replace(column, item);
    emit headerDataChanged(Qt::Horizontal, column, column);
}

/*!
    \since 4.2

    Returns the horizontal header item for \a column if one has been set;
    otherwise returns 0.

    \sa setHorizontalHeaderItem(), verticalHeaderItem()
*/
QStandardItem *QStandardItemModel::horizontalHeaderItem(int column) const
{
    Q_D(const QStandardItemModel);
    if ((column < 0) || (column >= columnCount()))
        return 0;
    return d->columnHeaderItems.at(column);
}

/*!
    \since 4.2

    Sets the vertical header item for \a row to \a item.  The model takes
    ownership of the item. If necessary, the row count is increased to fit the
    item. The previous header item (if there was one) is deleted.

    \sa verticalHeaderItem(), setVerticalHeaderLabels(),
    setHorizontalHeaderItem()
*/
void QStandardItemModel::setVerticalHeaderItem(int row, QStandardItem *item)
{
    Q_D(QStandardItemModel);
    if (row < 0)
        return;
    if (rowCount() <= row)
        setRowCount(row + 1);

    QStandardItem *oldItem = d->rowHeaderItems.at(row);
    if (item == oldItem)
        return;

    if (item) {
        if (item->model() == 0) {
            item->d_func()->setModel(this);
        } else {
            qWarning("QStandardItem::setVerticalHeaderItem: Ignoring duplicate insertion of item %p",
                     item);
            return;
        }
    }

    if (oldItem)
        oldItem->d_func()->setModel(0);
    delete oldItem;

    d->rowHeaderItems.replace(row, item);
    emit headerDataChanged(Qt::Vertical, row, row);
}

/*!
    \since 4.2

    Returns the vertical header item for row \a row if one has been set;
    otherwise returns 0.

    \sa setVerticalHeaderItem(), horizontalHeaderItem()
*/
QStandardItem *QStandardItemModel::verticalHeaderItem(int row) const
{
    Q_D(const QStandardItemModel);
    if ((row < 0) || (row >= rowCount()))
        return 0;
    return d->rowHeaderItems.at(row);
}

/*!
    \since 4.2

    Sets the horizontal header labels using \a labels. If necessary, the
    column count is increased to the size of \a labels.

    \sa setHorizontalHeaderItem()
*/
void QStandardItemModel::setHorizontalHeaderLabels(const QStringList &labels)
{
    Q_D(QStandardItemModel);
    if (columnCount() < labels.count())
        setColumnCount(labels.count());
    for (int i = 0; i < labels.count(); ++i) {
        QStandardItem *item = horizontalHeaderItem(i);
        if (!item) {
            item = d->createItem();
            setHorizontalHeaderItem(i, item);
        }
        item->setText(labels.at(i));
    }
}

/*!
    \since 4.2

    Sets the vertical header labels using \a labels. If necessary, the row
    count is increased to the size of \a labels.

    \sa setVerticalHeaderItem()
*/
void QStandardItemModel::setVerticalHeaderLabels(const QStringList &labels)
{
    Q_D(QStandardItemModel);
    if (rowCount() < labels.count())
        setRowCount(labels.count());
    for (int i = 0; i < labels.count(); ++i) {
        QStandardItem *item = verticalHeaderItem(i);
        if (!item) {
            item = d->createItem();
            setVerticalHeaderItem(i, item);
        }
        item->setText(labels.at(i));
    }
}

/*!
    \since 4.2

    Sets the item prototype for the model to the specified \a item. The model
    takes ownership of the prototype.

    The item prototype acts as a QStandardItem factory, by relying on the
    QStandardItem::clone() functi