qlistwidget.cpp

奇趣公司比较新的qt/emd版本

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#include "qlistwidget.h"

#ifndef QT_NO_LISTWIDGET
#include <qitemdelegate.h>
#include <private/qlistview_p.h>
#include <private/qwidgetitemdata_p.h>
#include <private/qlistwidget_p.h>

// workaround for VC++ 6.0 linker bug (?)
typedef bool(*LessThan)(const QPair<QListWidgetItem*,int>&,const QPair<QListWidgetItem*,int>&);

class QListWidgetMimeData : public QMimeData
{
    Q_OBJECT
public:
    QList<QListWidgetItem*> items;
};

#include "qlistwidget.moc"

QListModel::QListModel(QListWidget *parent)
    : QAbstractListModel(parent)
{
}

QListModel::~QListModel()
{
    clear();
}

void QListModel::clear()
{
    for (int i = 0; i < items.count(); ++i) {
        if (items.at(i)) {
            items.at(i)->d->id = -1;
            items.at(i)->view = 0;
            delete items.at(i);
        }
    }
    items.clear();
    reset();
}

QListWidgetItem *QListModel::at(int row) const
{
    return items.value(row);
}

void QListModel::remove(QListWidgetItem *item)
{
    if (!item)
        return;
    int row = items.indexOf(item); // ### use index(item) - it's faster
    Q_ASSERT(row != -1);
    beginRemoveRows(QModelIndex(), row, row);
    items.at(row)->d->id = -1;
    items.at(row)->view = 0;
    items.removeAt(row);
    endRemoveRows();
}

void QListModel::insert(int row, QListWidgetItem *item)
{
    if (!item)
        return;

    item->view = ::qobject_cast<QListWidget*>(QObject::parent());
    if (item->view && item->view->isSortingEnabled()) {
        // sorted insertion
        QList<QListWidgetItem*>::iterator it;
        it = sortedInsertionIterator(items.begin(), items.end(),
                                     item->view->sortOrder(), item);
        row = qMax(it - items.begin(), 0);
    } else {
        if (row < 0)
            row = 0;
        else if (row > items.count())
            row = items.count();
    }
    beginInsertRows(QModelIndex(), row, row);
    items.insert(row, item);
    item->d->id = row;
    endInsertRows();
}

void QListModel::insert(int row, const QStringList &labels)
{
    const int count = labels.count();
    if (count <= 0)
        return;
    QListWidget *view = ::qobject_cast<QListWidget*>(QObject::parent());
    if (view && view->isSortingEnabled()) {
        // sorted insertion
        for (int i = 0; i < count; ++i) {
            QListWidgetItem *item = new QListWidgetItem(labels.at(i));
            insert(row, item);
        }
    } else {
        if (row < 0)
            row = 0;
        else if (row > items.count())
            row = items.count();
        beginInsertRows(QModelIndex(), row, row + count - 1);
        for (int i = 0; i < count; ++i) {
            QListWidgetItem *item = new QListWidgetItem(labels.at(i));
            item->d->id = row;
            item->view = ::qobject_cast<QListWidget*>(QObject::parent());
            items.insert(row++, item);
        }
        endInsertRows();
    }
}

QListWidgetItem *QListModel::take(int row)
{
    if (row < 0 || row >= items.count())
        return 0;

    beginRemoveRows(QModelIndex(), row, row);
    items.at(row)->d->id = -1;
    items.at(row)->view = 0;
    QListWidgetItem *item = items.takeAt(row);
    endRemoveRows();
    return item;
}

int QListModel::rowCount(const QModelIndex &parent) const
{
    return parent.isValid() ? 0 : items.count();
}

QModelIndex QListModel::index(QListWidgetItem *item) const
{
    if (!item || !item->view || static_cast<const QListModel *>(item->view->model()) != this
        || items.isEmpty())
        return QModelIndex();
    int row;
    const int id = item->d->id;
    if (id >= 0 && id < items.count() && items.at(id) == item) {
        row = id;
    } else { // we need to search for the item
        row = items.lastIndexOf(item);  // lastIndexOf is an optimization in favor of indexOf
        if (row == -1) // not found
            return QModelIndex();
        item->d->id = row;
    }
    return createIndex(row, 0, item);
}

QModelIndex QListModel::index(int row, int column, const QModelIndex &parent) const
{
    if (hasIndex(row, column, parent))
        return createIndex(row, column, items.at(row));
    return QModelIndex();
}

QVariant QListModel::data(const QModelIndex &index, int role) const
{
    if (!index.isValid() || index.row() >= items.count())
        return QVariant();
    return items.at(index.row())->data(role);
}

bool QListModel::setData(const QModelIndex &index, const QVariant &value, int role)
{
    if (!index.isValid() || index.row() >= items.count())
        return false;
    items.at(index.row())->setData(role, value);
    return true;
}

QMap<int, QVariant> QListModel::itemData(const QModelIndex &index) const
{
    QMap<int, QVariant> roles;
    if (!index.isValid() || index.row() >= items.count())
        return roles;
    QListWidgetItem *itm = items.at(index.row());
    for (int i = 0; i < itm->values.count(); ++i) {
        roles.insert(itm->values.at(i).role,
                     itm->values.at(i).value);
    }
    return roles;
}

bool QListModel::insertRows(int row, int count, const QModelIndex &parent)
{
    if (count < 1 || row < 0 || row > rowCount() || parent.isValid())
        return false;

    beginInsertRows(QModelIndex(), row, row + count - 1);
    QListWidget *view = ::qobject_cast<QListWidget*>(QObject::parent());
    QListWidgetItem *itm = 0;

    for (int r = row; r < row + count; ++r) {
        itm = new QListWidgetItem;
        itm->view = view;
        itm->d->id = r;
        items.insert(r, itm);
    }

    endInsertRows();
    return true;
}

bool QListModel::removeRows(int row, int count, const QModelIndex &parent)
{
    if (count < 1 || row < 0 || (row + count) > rowCount() || parent.isValid())
        return false;

    beginRemoveRows(QModelIndex(), row, row + count - 1);
    QListWidgetItem *itm = 0;
    for (int r = row; r < row + count; ++r) {
        itm = items.takeAt(row);
        itm->view = 0;
        itm->d->id = -1;
        delete itm;
    }
    endRemoveRows();
    return true;
}

Qt::ItemFlags QListModel::flags(const QModelIndex &index) const
{
    if (!index.isValid() || index.row() >= items.count() || index.model() != this)
        return Qt::ItemIsDropEnabled; // we allow drops outside the items
    return items.at(index.row())->flags();
}

void QListModel::sort(int column, Qt::SortOrder order)
{
    if (column != 0)
        return;

    emit layoutAboutToBeChanged();

    QModelIndexList fromIndexes;
    QVector < QPair<QListWidgetItem*,int> > sorting(items.count());
    for (int i = 0; i < items.count(); ++i) {
        QListWidgetItem *item = items.at(i);
        sorting[i].first = item;
        sorting[i].second = i;
        fromIndexes.append(createIndex(i, 0, item));
    }

    LessThan compare = (order == Qt::AscendingOrder ? &itemLessThan : &itemGreaterThan);
    qSort(sorting.begin(), sorting.end(), compare);

    QModelIndexList toIndexes;
    for (int r = 0; r < sorting.count(); ++r) {
        QListWidgetItem *item = sorting.at(r).first;
        items[r] = item;
        toIndexes.append(createIndex(sorting.at(r).second, 0, item));
    }
    changePersistentIndexList(fromIndexes, toIndexes);

    emit layoutChanged();
}

/**
 * This function assumes that all items in the model except the items that are between
 * (inclusive) start and end are sorted.
 * With these assumptions, this function can ensure that the model is sorted in a
 * much more efficient way than doing a naive 'sort everything'.
 * (provided that the range is relatively small compared to the total number of items)
 */
void QListModel::ensureSorted(int column, Qt::SortOrder order, int start, int end)
{
    if (column != 0)
        return;

    int count = end - start + 1;
    QVector < QPair<QListWidgetItem*,int> > sorting(count);
    for (int i = 0; i < count; ++i) {
        sorting[i].first = items.at(start + i);
        sorting[i].second = start + i;
    }

    LessThan compare = (order == Qt::AscendingOrder ? &itemLessThan : &itemGreaterThan);
    qSort(sorting.begin(), sorting.end(), compare);

    QModelIndexList oldPersistentIndexes = persistentIndexList();
    QModelIndexList newPersistentIndexes = oldPersistentIndexes;
    QList<QListWidgetItem*> tmp = items;
    QList<QListWidgetItem*>::iterator lit = tmp.begin();
    bool changed = false;
    for (int i = 0; i < count; ++i) {
        int oldRow = sorting.at(i).second;
        QListWidgetItem *item = tmp.takeAt(oldRow);
        lit = sortedInsertionIterator(lit, tmp.end(), order, item);
        int newRow = qMax(lit - tmp.begin(), 0);
        lit = tmp.insert(lit, item);
        if (newRow != oldRow) {
            changed = true;
            for (int j = i + 1; j < count; ++j) {
                int otherRow = sorting.at(j).second;
                if (oldRow < otherRow && newRow >= otherRow)
                    --sorting[j].second;
                else if (oldRow > otherRow && newRow <= otherRow)
                    ++sorting[j].second;
            }
            for (int k = 0; k < newPersistentIndexes.count(); ++k) {
                QModelIndex pi = newPersistentIndexes.at(k);
                int oldPersistentRow = pi.row();
                int newPersistentRow = oldPersistentRow;
                if (oldPersistentRow == oldRow)
                    newPersistentRow = newRow;
                else if (oldRow < oldPersistentRow && newRow >= oldPersistentRow)
                    newPersistentRow = oldPersistentRow - 1;
                else if (oldRow > oldPersistentRow && newRow <= oldPersistentRow)
                    newPersistentRow = oldPersistentRow + 1;
                if (newPersistentRow != oldPersistentRow)
                    newPersistentIndexes[k] = createIndex(newPersistentRow,
                                                          pi.column(), pi.internalPointer());
            }
        }
    }

    if (changed) {
        emit layoutAboutToBeChanged();
        items = tmp;
        changePersistentIndexList(oldPersistentIndexes, newPersistentIndexes);
        emit layoutChanged();
    }
}

bool QListModel::itemLessThan(const QPair<QListWidgetItem*,int> &left,
                              const QPair<QListWidgetItem*,int> &right)
{
    return (*left.first) < (*right.first);
}

bool QListModel::itemGreaterThan(const QPair<QListWidgetItem*,int> &left,
                                 const QPair<QListWidgetItem*,int> &right)
{
    return !((*left.first) < (*right.first));
}

QList<QListWidgetItem*>::iterator QListModel::sortedInsertionIterator(
    const QList<QListWidgetItem*>::iterator &begin,
    const QList<QListWidgetItem*>::iterator &end,
    Qt::SortOrder order, QListWidgetItem *item)
{
    if (order == Qt::AscendingOrder)
        return qLowerBound(begin, end, item, QListModelLessThan());
    return qLowerBound(begin, end, item, QListModelGreaterThan());
}

void QListModel::itemChanged(QListWidgetItem *item)
{
    QModelIndex idx = index(item);
    emit dataChanged(idx, idx);
}

QStringList QListModel::mimeTypes() const
{
    const QListWidget *view = ::qobject_cast<const QListWidget*>(QObject::parent());
    return view->mimeTypes();
}

QMimeData *QListModel::internalMimeData()  const
{
    return QAbstractItemModel::mimeData(cachedIndexes);
}

QMimeData *QListModel::mimeData(const QModelIndexList &indexes) const
{
    QList<QListWidgetItem*> itemlist;
    for (int i = 0; i < indexes.count(); ++i)
        itemlist << at(indexes.at(i).row());
    const QListWidget *view = ::qobject_cast<const QListWidget*>(QObject::parent());

    cachedIndexes = indexes;
    QMimeData *mimeData = view->mimeData(itemlist);
    cachedIndexes.clear();
    return mimeData;
}

#ifndef QT_NO_DRAGANDDROP
bool QListModel::dropMimeData(const QMimeData *data, Qt::DropAction action,
                              int row, int column, const QModelIndex &index)
{
    Q_UNUSED(column);
    QListWidget *view = ::qobject_cast<QListWidget*>(QObject::parent());
    if (index.isValid())
        row = index.row();
    else if (row == -1)
        row = items.count();

    return view->dropMimeData(row, data, action);
}

Qt::DropActions QListModel::supportedDropActions() const
{
    const QListWidget *view = ::qobject_cast<const QListWidget*>(QObject::parent());
    return view->supportedDropActions();
}
#endif // QT_NO_DRAGANDDROP

/*!
    \class QListWidgetItem
    \brief The QListWidgetItem class provides an item for use with the
    QListWidget item view class.

    \ingroup model-view

    QListWidgetItem is used to represent items in a list provided by the
    QListWidget class. Each item can hold several pieces of information,
    and will display these appropriately.

    The item view convenience classes use a classic item-based interface
    rather than a pure model/view approach. For a more flexible list view
    widget, consider using the QListView class with a standard model.

    List items can be automatically inserted into a list when they are
    constructed by specifying the list widget:

    \quotefile snippets/qlistwidget-using/mainwindow.cpp
    \skipto new QListWidgetItem(tr("Hazel
    \printuntil new QListWidgetItem(tr("Hazel

    They can also be created without a parent widget, and later inserted into
    a list (see \l{QListWidget::insertItem()}).