qcolumnview.cpp

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// Copyright (C) 2020 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include <qglobal.h>
#include "qcolumnview.h"
 
#if QT_CONFIG(columnview)
 
#include "qcolumnview_p.h"
#include "qcolumnviewgrip_p.h"
 
#include <qlistview.h>
#include <qabstractitemdelegate.h>
#include <qscrollbar.h>
#include <qpainter.h>
#include <qdebug.h>
 
QT_BEGIN_NAMESPACE
 
QColumnView::QColumnView(QWidget * parent)
:  QAbstractItemView(*new QColumnViewPrivate, parent)
{
    Q_D(QColumnView);
    d->initialize();
}
 
QColumnView::QColumnView(QColumnViewPrivate & dd, QWidget * parent)
:  QAbstractItemView(dd, parent)
{
    Q_D(QColumnView);
    d->initialize();
}
 
void QColumnViewPrivate::initialize()
{
    Q_Q(QColumnView);
    q->setTextElideMode(Qt::ElideMiddle);
#if QT_CONFIG(animation)
    animationConnection =
        QObjectPrivate::connect(&currentAnimation, &QPropertyAnimation::finished,
                                this, &QColumnViewPrivate::changeCurrentColumn);
    currentAnimation.setTargetObject(hbar);
    currentAnimation.setPropertyName("value");
    currentAnimation.setEasingCurve(QEasingCurve::InOutQuad);
#endif // animation
    delete itemDelegate;
    q->setItemDelegate(new QColumnViewDelegate(q));
}
 
void QColumnViewPrivate::clearConnections()
{
#if QT_CONFIG(animation)
    QObject::disconnect(animationConnection);
#endif
    for (const QMetaObject::Connection &connection : gripConnections)
        QObject::disconnect(connection);
    const auto copy = viewConnections;  // disconnectView modifies this container
    for (auto it = copy.keyBegin(); it != copy.keyEnd(); ++it)
        disconnectView(*it);
}
 
 
QColumnView::~QColumnView()
{
    Q_D(QColumnView);
    d->clearConnections();
}
 
void QColumnView::setResizeGripsVisible(bool visible)
{
    Q_D(QColumnView);
    if (d->showResizeGrips == visible)
        return;
    d->showResizeGrips = visible;
    d->gripConnections.clear();
    for (QAbstractItemView *view : std::as_const(d->columns)) {
        if (visible) {
            QColumnViewGrip *grip = new QColumnViewGrip(view);
            view->setCornerWidget(grip);
            d->gripConnections.push_back(
                QObjectPrivate::connect(grip, &QColumnViewGrip::gripMoved,
                                        d, &QColumnViewPrivate::gripMoved)
            );
        } else {
            QWidget *widget = view->cornerWidget();
            view->setCornerWidget(nullptr);
            widget->deleteLater();
        }
    }
}
 
bool QColumnView::resizeGripsVisible() const
{
    Q_D(const QColumnView);
    return d->showResizeGrips;
}
 
void QColumnView::setModel(QAbstractItemModel *model)
{
    Q_D(QColumnView);
    if (model == d->model)
        return;
    d->closeColumns();
    QAbstractItemView::setModel(model);
}
 
void QColumnView::setRootIndex(const QModelIndex &index)
{
    Q_D(QColumnView);
    if (!model())
        return;
 
    d->closeColumns();
    Q_ASSERT(d->columns.size() == 0);
 
    QAbstractItemView *view = d->createColumn(index, true);
    if (view->selectionModel())
        view->selectionModel()->deleteLater();
    if (view->model())
        view->setSelectionModel(selectionModel());
 
    QAbstractItemView::setRootIndex(index);
    d->updateScrollbars();
}
 
bool QColumnView::isIndexHidden(const QModelIndex &index) const
{
    Q_UNUSED(index);
    return false;
}
 
QModelIndex QColumnView::indexAt(const QPoint &point) const
{
    Q_D(const QColumnView);
    for (int i = 0; i < d->columns.size(); ++i) {
        QPoint topLeft = d->columns.at(i)->frameGeometry().topLeft();
        QPoint adjustedPoint(point.x() - topLeft.x(), point.y() - topLeft.y());
        QModelIndex index = d->columns.at(i)->indexAt(adjustedPoint);
        if (index.isValid())
            return index;
    }
    return QModelIndex();
}
 
QRect QColumnView::visualRect(const QModelIndex &index) const
{
    if (!index.isValid())
        return QRect();
 
    Q_D(const QColumnView);
    for (int i = 0; i < d->columns.size(); ++i) {
        QRect rect = d->columns.at(i)->visualRect(index);
        if (!rect.isNull()) {
            rect.translate(d->columns.at(i)->frameGeometry().topLeft());
            return rect;
        }
    }
    return QRect();
}
 
void QColumnView::scrollContentsBy(int dx, int dy)
{
    Q_D(QColumnView);
    if (d->columns.isEmpty() || dx == 0)
        return;
 
    dx = isRightToLeft() ? -dx : dx;
    for (int i = 0; i < d->columns.size(); ++i)
        d->columns.at(i)->move(d->columns.at(i)->x() + dx, 0);
    d->offset += dx;
    QAbstractItemView::scrollContentsBy(dx, dy);
}
 
void QColumnView::scrollTo(const QModelIndex &index, ScrollHint hint)
{
    Q_D(QColumnView);
    Q_UNUSED(hint);
    if (!index.isValid() || d->columns.isEmpty())
        return;
 
#if QT_CONFIG(animation)
    if (d->currentAnimation.state() == QPropertyAnimation::Running)
        return;
 
    d->currentAnimation.stop();
#endif // animation
 
    // Fill up what is needed to get to index
    d->closeColumns(index, true);
 
    QModelIndex indexParent = index.parent();
    // Find the left edge of the column that contains index
    int currentColumn = 0;
    int leftEdge = 0;
    while (currentColumn < d->columns.size()) {
        if (indexParent == d->columns.at(currentColumn)->rootIndex())
            break;
        leftEdge += d->columns.at(currentColumn)->width();
        ++currentColumn;
    }
 
    // Don't let us scroll above the root index
    if (currentColumn == d->columns.size())
        return;
 
    int indexColumn = currentColumn;
    // Find the width of what we want to show (i.e. the right edge)
    int visibleWidth = d->columns.at(currentColumn)->width();
    // We want to always try to show two columns
    if (currentColumn + 1 < d->columns.size()) {
        ++currentColumn;
        visibleWidth += d->columns.at(currentColumn)->width();
    }
 
    int rightEdge = leftEdge + visibleWidth;
    if (isRightToLeft()) {
        leftEdge = viewport()->width() - leftEdge;
        rightEdge = leftEdge - visibleWidth;
        qSwap(rightEdge, leftEdge);
    }
 
    // If it is already visible don't animate
    if (leftEdge > -horizontalOffset()
        && rightEdge <= ( -horizontalOffset() + viewport()->size().width())) {
            d->columns.at(indexColumn)->scrollTo(index);
            d->changeCurrentColumn();
            return;
    }
 
    int newScrollbarValue = 0;
    if (isRightToLeft()) {
        if (leftEdge < 0) {
            // scroll to the right
            newScrollbarValue = viewport()->size().width() - leftEdge;
        } else {
            // scroll to the left
            newScrollbarValue = rightEdge + horizontalOffset();
        }
    } else {
        if (leftEdge > -horizontalOffset()) {
            // scroll to the right
            newScrollbarValue = rightEdge - viewport()->size().width();
        } else {
            // scroll to the left
            newScrollbarValue = leftEdge;
        }
    }
 
#if QT_CONFIG(animation)
    if (const int animationDuration = style()->styleHint(QStyle::SH_Widget_Animation_Duration, nullptr, this)) {
        d->currentAnimation.setDuration(animationDuration);
        d->currentAnimation.setEndValue(newScrollbarValue);
        d->currentAnimation.start();
    } else
#endif // animation
    {
        horizontalScrollBar()->setValue(newScrollbarValue);
    }
}
 
QModelIndex QColumnView::moveCursor(CursorAction cursorAction, Qt::KeyboardModifiers modifiers)
{
    // the child views which have focus get to deal with this first and if
    // they don't accept it then it comes up this view and we only grip left/right
    Q_UNUSED(modifiers);
    if (!model())
        return QModelIndex();
 
    QModelIndex current = currentIndex();
    if (isRightToLeft()) {
        if (cursorAction == MoveLeft)
            cursorAction = MoveRight;
        else if (cursorAction == MoveRight)
            cursorAction = MoveLeft;
    }
    switch (cursorAction) {
    case MoveLeft:
        if (current.parent().isValid() && current.parent() != rootIndex())
            return (current.parent());
        else
            return current;
 
    case MoveRight:
        if (model()->hasChildren(current))
            return model()->index(0, 0, current);
        else
            return current.sibling(current.row() + 1, current.column());
 
    default:
        break;
    }
 
    return QModelIndex();
}
 
void QColumnView::resizeEvent(QResizeEvent *event)
{
    Q_D(QColumnView);
    d->doLayout();
    d->updateScrollbars();
    if (!isRightToLeft()) {
        int diff = event->oldSize().width() - event->size().width();
        if (diff < 0 && horizontalScrollBar()->isVisible()
            && horizontalScrollBar()->value() == horizontalScrollBar()->maximum()) {
            horizontalScrollBar()->setMaximum(horizontalScrollBar()->maximum() + diff);
        }
    }
    QAbstractItemView::resizeEvent(event);
}
 
void QColumnViewPrivate::updateScrollbars()
{
    Q_Q(QColumnView);
#if QT_CONFIG(animation)
    if (currentAnimation.state() == QPropertyAnimation::Running)
        return;
#endif // animation
 
    // find the total horizontal length of the laid out columns
    int horizontalLength = 0;
    if (!columns.isEmpty()) {
        horizontalLength = (columns.constLast()->x() + columns.constLast()->width()) - columns.constFirst()->x();
        if (horizontalLength <= 0) // reverse mode
            horizontalLength = (columns.constFirst()->x() + columns.constFirst()->width()) - columns.constLast()->x();
    }
 
    QSize viewportSize = viewport->size();
    if (horizontalLength < viewportSize.width() && hbar->value() == 0) {
        hbar->setRange(0, 0);
    } else {
        int visibleLength = qMin(horizontalLength + q->horizontalOffset(), viewportSize.width());
        int hiddenLength = horizontalLength - visibleLength;
        if (hiddenLength != hbar->maximum())
            hbar->setRange(0, hiddenLength);
    }
    if (!columns.isEmpty()) {
        int pageStepSize = columns.at(0)->width();
        if (pageStepSize != hbar->pageStep())
            hbar->setPageStep(pageStepSize);
    }
    bool visible = (hbar->maximum() > 0);
    if (visible != hbar->isVisible())
        hbar->setVisible(visible);
}
 
int QColumnView::horizontalOffset() const
{
    Q_D(const QColumnView);
    return d->offset;
}
 
int QColumnView::verticalOffset() const
{
    return 0;
}
 
QRegion QColumnView::visualRegionForSelection(const QItemSelection &selection) const
{
    int ranges = selection.size();
 
    if (ranges == 0)
        return QRect();
 
    // Note that we use the top and bottom functions of the selection range
    // since the data is stored in rows.
    int firstRow = selection.at(0).top();
    int lastRow = selection.at(0).top();
    for (int i = 0; i < ranges; ++i) {
        firstRow = qMin(firstRow, selection.at(i).top());
        lastRow = qMax(lastRow, selection.at(i).bottom());
    }
 
    QModelIndex firstIdx = model()->index(qMin(firstRow, lastRow), 0, rootIndex());
    QModelIndex lastIdx = model()->index(qMax(firstRow, lastRow), 0, rootIndex());
 
    if (firstIdx == lastIdx)
        return visualRect(firstIdx);
 
    QRegion firstRegion = visualRect(firstIdx);
    QRegion lastRegion = visualRect(lastIdx);
    return firstRegion.united(lastRegion);
}
 
void QColumnView::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags command)
{
    Q_UNUSED(rect);
    Q_UNUSED(command);
}
 
void QColumnView::setSelectionModel(QItemSelectionModel *newSelectionModel)
{
    Q_D(const QColumnView);
    for (int i = 0; i < d->columns.size(); ++i) {
        if (d->columns.at(i)->selectionModel() == selectionModel()) {
            d->columns.at(i)->setSelectionModel(newSelectionModel);
            break;
        }
    }
    QAbstractItemView::setSelectionModel(newSelectionModel);
}
 
QSize QColumnView::sizeHint() const
{
    Q_D(const QColumnView);
    QSize sizeHint;
    for (int i = 0; i < d->columns.size(); ++i) {
        sizeHint += d->columns.at(i)->sizeHint();
    }
    return sizeHint.expandedTo(QAbstractItemView::sizeHint());
}
 
void QColumnViewPrivate::gripMoved(int offset)
{
    Q_Q(QColumnView);
 
    QObject *grip = q->sender();
    Q_ASSERT(grip);
 
    if (q->isRightToLeft())
        offset = -1 * offset;
 
    bool found = false;
    for (int i = 0; i < columns.size(); ++i) {
        if (!found && columns.at(i)->cornerWidget() == grip) {
            found = true;
            columnSizes[i] = columns.at(i)->width();
            if (q->isRightToLeft())
                columns.at(i)->move(columns.at(i)->x() + offset, 0);
            continue;
        }
        if (!found)
            continue;
 
        int currentX = columns.at(i)->x();
        columns.at(i)->move(currentX + offset, 0);
    }
 
    updateScrollbars();
}
 
void QColumnViewPrivate::closeColumns(const QModelIndex &parent, bool build)
{
    if (columns.isEmpty())
        return;
 
    bool clearAll = !parent.isValid();
    bool passThroughRoot = false;
 
    QList<QModelIndex> dirsToAppend;
 
    // Find the last column that matches the parent's tree
    int currentColumn = -1;
    QModelIndex parentIndex = parent;
    while (currentColumn == -1 && parentIndex.isValid()) {
        if (columns.isEmpty())
            break;
        parentIndex = parentIndex.parent();
        if (root == parentIndex)
            passThroughRoot = true;
        if (!parentIndex.isValid())
            break;
        for (int i = columns.size() - 1; i >= 0; --i) {
            if (columns.at(i)->rootIndex() == parentIndex) {
                currentColumn = i;
                break;
            }
        }
        if (currentColumn == -1)
            dirsToAppend.append(parentIndex);
    }
 
    // Someone wants to go to an index that can be reached without changing
    // the root index, don't allow them
    if (!clearAll && !passThroughRoot && currentColumn == -1)
        return;
 
    if (currentColumn == -1 && parent.isValid())
        currentColumn = 0;
 
    // Optimization so we don't go deleting and then creating the same thing
    bool alreadyExists = false;
    if (build && columns.size() > currentColumn + 1) {
        bool viewingParent = (columns.at(currentColumn + 1)->rootIndex() == parent);
        bool viewingChild = (!model->hasChildren(parent)
                             && !columns.at(currentColumn + 1)->rootIndex().isValid());
        if (viewingParent || viewingChild) {
            currentColumn++;
            alreadyExists = true;
        }
    }
 
    // Delete columns that don't match our path
    for (int i = columns.size() - 1; i > currentColumn; --i) {
        QAbstractItemView* notShownAnymore = columns.at(i);
        columns.removeAt(i);
        notShownAnymore->setVisible(false);
        if (notShownAnymore != previewColumn) {
            notShownAnymore->deleteLater();
            disconnectView(notShownAnymore);
        }
    }
 
    if (columns.isEmpty()) {
        offset = 0;
        updateScrollbars();
    }
 
    // Now fill in missing columns
    while (!dirsToAppend.isEmpty()) {
        QAbstractItemView *newView = createColumn(dirsToAppend.takeLast(), true);
        if (!dirsToAppend.isEmpty())
            newView->setCurrentIndex(dirsToAppend.constLast());
    }
 
    if (build && !alreadyExists)
        createColumn(parent, false);
}
 
void QColumnViewPrivate::disconnectView(QAbstractItemView *view)
{
    const auto it = viewConnections.find(view);
    if (it == viewConnections.end())
        return;
    for (const QMetaObject::Connection &connection : it.value())
        QObject::disconnect(connection);
    viewConnections.erase(it);
}
 
void QColumnViewPrivate::clicked(const QModelIndex &index)
{
    Q_Q(QColumnView);
    QModelIndex parent = index.parent();
    QAbstractItemView *columnClicked = nullptr;
    for (int column = 0; column < columns.size(); ++column) {
        if (columns.at(column)->rootIndex() == parent) {
            columnClicked = columns[column];
            break;
        }
    }
    if (q->selectionModel() && columnClicked) {
        QItemSelectionModel::SelectionFlags flags = QItemSelectionModel::Current;
        if (columnClicked->selectionModel()->isSelected(index))
            flags |= QItemSelectionModel::Select;
        q->selectionModel()->setCurrentIndex(index, flags);
    }
}
 
QAbstractItemView *QColumnViewPrivate::createColumn(const QModelIndex &index, bool show)
{
    Q_Q(QColumnView);
    QAbstractItemView *view = nullptr;
    QMetaObject::Connection clickedConnection;
    if (model->hasChildren(index)) {
        view = q->createColumn(index);
        clickedConnection = QObjectPrivate::connect(view, &QAbstractItemView::clicked,
                                                    this, &QColumnViewPrivate::clicked);
    } else {
        if (!previewColumn)
            setPreviewWidget(new QWidget(q));
        view = previewColumn;
        view->setMinimumWidth(qMax(view->minimumWidth(), previewWidget->minimumWidth()));
    }
 
    viewConnections[view] = {
        QObject::connect(view, &QAbstractItemView::activated, q, &QColumnView::activated),
        QObject::connect(view, &QAbstractItemView::clicked, q, &QColumnView::clicked),
        QObject::connect(view, &QAbstractItemView::doubleClicked, q, &QColumnView::doubleClicked),
        QObject::connect(view, &QAbstractItemView::entered, q, &QColumnView::entered),
        QObject::connect(view, &QAbstractItemView::pressed, q, &QColumnView::pressed),
        clickedConnection
    };
 
    view->setFocusPolicy(Qt::NoFocus);
    view->setParent(viewport);
    Q_ASSERT(view);
 
    // Setup corner grip
    if (showResizeGrips) {
        QColumnViewGrip *grip = new QColumnViewGrip(view);
        view->setCornerWidget(grip);
        gripConnections.push_back(
            QObjectPrivate::connect(grip, &QColumnViewGrip::gripMoved,
                                    this, &QColumnViewPrivate::gripMoved)
        );
    }
 
    if (columnSizes.size() > columns.size()) {
        view->setGeometry(0, 0, columnSizes.at(columns.size()), viewport->height());
    } else {
        int initialWidth = view->sizeHint().width();
        if (q->isRightToLeft())
            view->setGeometry(viewport->width() - initialWidth, 0, initialWidth, viewport->height());
        else
            view->setGeometry(0, 0, initialWidth, viewport->height());
        columnSizes.resize(qMax(columnSizes.size(), columns.size() + 1));
        columnSizes[columns.size()] = initialWidth;
    }
    if (!columns.isEmpty() && columns.constLast()->isHidden())
        columns.constLast()->setVisible(true);
 
    columns.append(view);
    doLayout();
    updateScrollbars();
    if (show && view->isHidden())
        view->setVisible(true);
    return view;
}
 
QAbstractItemView *QColumnView::createColumn(const QModelIndex &index)
{
    QListView *view = new QListView(viewport());
 
    initializeColumn(view);
 
    view->setRootIndex(index);
    if (model()->canFetchMore(index))
        model()->fetchMore(index);
 
    return view;
}
 
void QColumnView::initializeColumn(QAbstractItemView *column) const
{
    Q_D(const QColumnView);
 
    column->setFrameShape(QFrame::NoFrame);
    column->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    column->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOn);
    column->setMinimumWidth(100);
    column->setAttribute(Qt::WA_MacShowFocusRect, false);
 
#if QT_CONFIG(draganddrop)
    column->setDragDropMode(dragDropMode());
    column->setDragDropOverwriteMode(dragDropOverwriteMode());
    column->setDropIndicatorShown(showDropIndicator());
#endif
    column->setAlternatingRowColors(alternatingRowColors());
    column->setAutoScroll(hasAutoScroll());
    column->setEditTriggers(editTriggers());
    column->setHorizontalScrollMode(horizontalScrollMode());
    column->setIconSize(iconSize());
    column->setSelectionBehavior(selectionBehavior());
    column->setSelectionMode(selectionMode());
    column->setTabKeyNavigation(tabKeyNavigation());
    column->setTextElideMode(textElideMode());
    column->setVerticalScrollMode(verticalScrollMode());
 
    column->setModel(model());
 
    // Copy the custom delegate per row
    for (auto i = d->rowDelegates.cbegin(), end = d->rowDelegates.cend(); i != end; ++i)
        column->setItemDelegateForRow(i.key(), i.value());
 
    // set the delegate to be the columnview delegate
    QAbstractItemDelegate *delegate = column->itemDelegate();
    column->setItemDelegate(d->itemDelegate);
    delete delegate;
}
 
QWidget *QColumnView::previewWidget() const
{
    Q_D(const QColumnView);
    return d->previewWidget;
}
 
void QColumnView::setPreviewWidget(QWidget *widget)
{
    Q_D(QColumnView);
    d->setPreviewWidget(widget);
}
 
void QColumnViewPrivate::setPreviewWidget(QWidget *widget)
{
    Q_Q(QColumnView);
    if (previewColumn) {
        if (!columns.isEmpty() && columns.constLast() == previewColumn)
            columns.removeLast();
        previewColumn->deleteLater();
    }
    QColumnViewPreviewColumn *column = new QColumnViewPreviewColumn(q);
    column->setPreviewWidget(widget);
    previewColumn = column;
    previewColumn->hide();
    previewColumn->setFrameShape(QFrame::NoFrame);
    previewColumn->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOn);
    previewColumn->setSelectionMode(QAbstractItemView::NoSelection);
    previewColumn->setMinimumWidth(qMax(previewColumn->verticalScrollBar()->width(),
                previewColumn->minimumWidth()));
    previewWidget = widget;
    previewWidget->setParent(previewColumn->viewport());
}
 
void QColumnView::setColumnWidths(const QList<int> &list)
{
    Q_D(QColumnView);
    int i = 0;
    const int listCount = list.size();
    const int count = qMin(listCount, d->columns.size());
    for (; i < count; ++i) {
        d->columns.at(i)->resize(list.at(i), d->columns.at(i)->height());
        d->columnSizes[i] = list.at(i);
    }
 
    d->columnSizes.reserve(listCount);
    for (; i < listCount; ++i)
        d->columnSizes.append(list.at(i));
}
 
QList<int> QColumnView::columnWidths() const
{
    Q_D(const QColumnView);
    QList<int> list;
    const int columnCount = d->columns.size();
    list.reserve(columnCount);
    for (int i = 0; i < columnCount; ++i)
        list.append(d->columnSizes.at(i));
    return list;
}
 
void QColumnView::rowsInserted(const QModelIndex &parent, int start, int end)
{
    QAbstractItemView::rowsInserted(parent, start, end);
    d_func()->checkColumnCreation(parent);
}
 
void QColumnView::currentChanged(const QModelIndex &current, const QModelIndex &previous)
{
    Q_D(QColumnView);
    if (!current.isValid()) {
        QAbstractItemView::currentChanged(current, previous);
        return;
    }
 
    QModelIndex currentParent = current.parent();
    // optimize for just moving up/down in a list where the child view doesn't change
    if (currentParent == previous.parent()
            && model()->hasChildren(current) && model()->hasChildren(previous)) {
        for (int i = 0; i < d->columns.size(); ++i) {
            if (currentParent == d->columns.at(i)->rootIndex()) {
                if (d->columns.size() > i + 1) {
                    QAbstractItemView::currentChanged(current, previous);
                    return;
                }
                break;
            }
        }
    }
 
    // Scrolling to the right we need to have an empty spot
    bool found = false;
    if (currentParent == previous) {
        for (int i = 0; i < d->columns.size(); ++i) {
            if (currentParent == d->columns.at(i)->rootIndex()) {
                found = true;
                if (d->columns.size() < i + 2) {
                    d->createColumn(current, false);
                }
                break;
            }
        }
    }
    if (!found)
        d->closeColumns(current, true);
 
    if (!model()->hasChildren(current))
        emit updatePreviewWidget(current);
 
    QAbstractItemView::currentChanged(current, previous);
}
 
/*
    We have change the current column and need to update focus and selection models
    on the new current column.
*/
void QColumnViewPrivate::changeCurrentColumn()
{
    Q_Q(QColumnView);
    if (columns.isEmpty())
        return;
 
    QModelIndex current = q->currentIndex();
    if (!current.isValid())
        return;
 
    // We might have scrolled far to the left so we need to close all of the children
    closeColumns(current, true);
 
    // Set up the "current" column with focus
    int currentColumn = qMax(0, columns.size() - 2);
    QAbstractItemView *parentColumn = columns.at(currentColumn);
    if (q->hasFocus())
        parentColumn->setFocus(Qt::OtherFocusReason);
    q->setFocusProxy(parentColumn);
 
    // find the column that is our current selection model and give it a new one.
    for (int i = 0; i < columns.size(); ++i) {
        if (columns.at(i)->selectionModel() == q->selectionModel()) {
            QItemSelectionModel *replacementSelectionModel =
                new QItemSelectionModel(parentColumn->model());
            replacementSelectionModel->setCurrentIndex(
                q->selectionModel()->currentIndex(), QItemSelectionModel::Current);
            replacementSelectionModel->select(
                q->selectionModel()->selection(), QItemSelectionModel::Select);
            QAbstractItemView *view = columns.at(i);
            view->setSelectionModel(replacementSelectionModel);
            view->setFocusPolicy(Qt::NoFocus);
            if (columns.size() > i + 1) {
                const QModelIndex newRootIndex = columns.at(i + 1)->rootIndex();
                if (newRootIndex.isValid())
                    view->setCurrentIndex(newRootIndex);
            }
            break;
        }
    }
    parentColumn->selectionModel()->deleteLater();
    parentColumn->setFocusPolicy(Qt::StrongFocus);
    parentColumn->setSelectionModel(q->selectionModel());
    // We want the parent selection to stay highlighted (but dimmed depending upon the color theme)
    if (currentColumn > 0) {
        parentColumn = columns.at(currentColumn - 1);
        if (parentColumn->currentIndex() != current.parent())
            parentColumn->setCurrentIndex(current.parent());
    }
 
    if (columns.constLast()->isHidden()) {
        columns.constLast()->setVisible(true);
    }
    if (columns.constLast()->selectionModel())
        columns.constLast()->selectionModel()->clear();
    updateScrollbars();
}
 
void QColumnView::selectAll()
{
    if (!model() || !selectionModel())
        return;
 
    QModelIndexList indexList = selectionModel()->selectedIndexes();
    QModelIndex parent = rootIndex();
    QItemSelection selection;
    if (indexList.size() >= 1)
        parent = indexList.at(0).parent();
    if (indexList.size() == 1) {
        parent = indexList.at(0);
        if (!model()->hasChildren(parent))
            parent = parent.parent();
        else
            selection.append(QItemSelectionRange(parent, parent));
    }
 
    QModelIndex tl = model()->index(0, 0, parent);
    QModelIndex br = model()->index(model()->rowCount(parent) - 1,
                                    model()->columnCount(parent) - 1,
                                    parent);
    selection.append(QItemSelectionRange(tl, br));
    selectionModel()->select(selection, QItemSelectionModel::ClearAndSelect);
}
 
/*
 * private object implementation
 */
QColumnViewPrivate::QColumnViewPrivate()
:  QAbstractItemViewPrivate()
,showResizeGrips(true)
,offset(0)
,previewWidget(nullptr)
,previewColumn(nullptr)
{
}
 
QColumnViewPrivate::~QColumnViewPrivate()
{
}
 
void QColumnViewPrivate::columnsInserted(const QModelIndex &parent, int start, int end)
{
    QAbstractItemViewPrivate::columnsInserted(parent, start, end);
    checkColumnCreation(parent);
}
 
void QColumnViewPrivate::checkColumnCreation(const QModelIndex &parent)
{
    if (parent == q_func()->currentIndex() && model->hasChildren(parent)) {
        //the parent has children and is the current
        //let's try to find out if there is already a mapping that is good
        for (int i = 0; i < columns.size(); ++i) {
            QAbstractItemView *view = columns.at(i);
            if (view->rootIndex() == parent) {
                if (view == previewColumn) {
                    //let's recreate the parent
                    closeColumns(parent, false);
                    createColumn(parent, true /*show*/);
                }
                break;
            }
        }
    }
}
 
void QColumnViewPrivate::doLayout()
{
    Q_Q(QColumnView);
    if (!model || columns.isEmpty())
        return;
 
    int viewportHeight = viewport->height();
    int x = columns.at(0)->x();
 
    if (q->isRightToLeft()) {
        x = viewport->width() + q->horizontalOffset();
        for (int i = 0; i < columns.size(); ++i) {
            QAbstractItemView *view = columns.at(i);
            x -= view->width();
            if (x != view->x() || viewportHeight != view->height())
                view->setGeometry(x, 0, view->width(), viewportHeight);
        }
    } else {
        for (int i = 0; i < columns.size(); ++i) {
            QAbstractItemView *view = columns.at(i);
            int currentColumnWidth = view->width();
            if (x != view->x() || viewportHeight != view->height())
                view->setGeometry(x, 0, currentColumnWidth, viewportHeight);
            x += currentColumnWidth;
        }
    }
}
 
void QColumnViewDelegate::paint(QPainter *painter,
                          const QStyleOptionViewItem &option,
                          const QModelIndex &index) const
{
    bool reverse = (option.direction == Qt::RightToLeft);
    int width = ((option.rect.height() * 2) / 3);
    // Modify the options to give us room to add an arrow
    QStyleOptionViewItem opt = option;
    if (reverse)
        opt.rect.adjust(width,0,0,0);
    else
        opt.rect.adjust(0,0,-width,0);
 
    if (!(index.model()->flags(index) & Qt::ItemIsEnabled)) {
        opt.showDecorationSelected = true;
        opt.state |= QStyle::State_Selected;
    }
 
    QStyledItemDelegate::paint(painter, opt, index);
 
    if (reverse)
        opt.rect = QRect(option.rect.x(), option.rect.y(), width, option.rect.height());
    else
        opt.rect = QRect(option.rect.x() + option.rect.width() - width, option.rect.y(),
                         width, option.rect.height());
 
    // Draw >
    if (index.model()->hasChildren(index)) {
        const QWidget *view = opt.widget;
        QStyle *style = view ? view->style() : QApplication::style();
        style->drawPrimitive(QStyle::PE_IndicatorColumnViewArrow, &opt, painter, view);
    }
}
 
QT_END_NAMESPACE
 
#include "moc_qcolumnview.cpp"
 
#endif // QT_CONFIG(columnview)