- Qt 5.5
- Qt Widgets
- Editable Tree Model Example
- treemodel.cpp Example File
- Qt 5.5.1 Reference Documentation

# treemodel.cpp Example File

itemviews/editabletreemodel/treemodel.cpp

    /****************************************************************************
    **
    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** This file is part of the examples of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
    ** You may use this file under the terms of the BSD license as follows:
    **
    ** "Redistribution and use in source and binary forms, with or without
    ** modification, are permitted provided that the following conditions are
    ** met:
    **   * Redistributions of source code must retain the above copyright
    **     notice, this list of conditions and the following disclaimer.
    **   * Redistributions in binary form must reproduce the above copyright
    **     notice, this list of conditions and the following disclaimer in
    **     the documentation and/or other materials provided with the
    **     distribution.
    **   * Neither the name of The Qt Company Ltd nor the names of its
    **     contributors may be used to endorse or promote products derived
    **     from this software without specific prior written permission.
    **
    **
    ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
    **
    ** $QT_END_LICENSE$
    **
    ****************************************************************************/

    #include <QtWidgets>

    #include "treeitem.h"
    #include "treemodel.h"

    TreeModel::TreeModel(const QStringList &headers, const QString &data, QObject *parent)
        : QAbstractItemModel(parent)
    {
        QVector<QVariant> rootData;
        foreach (QString header, headers)
            rootData << header;

        rootItem = new TreeItem(rootData);
        setupModelData(data.split(QString("\n")), rootItem);
    }

    TreeModel::~TreeModel()
    {
        delete rootItem;
    }

    int TreeModel::columnCount(const QModelIndex & /* parent */) const
    {
        return rootItem->columnCount();
    }

    QVariant TreeModel::data(const QModelIndex &index, int role) const
    {
        if (!index.isValid())
            return QVariant();

        if (role != Qt::DisplayRole && role != Qt::EditRole)
            return QVariant();

        TreeItem *item = getItem(index);

        return item->data(index.column());
    }

    Qt::ItemFlags TreeModel::flags(const QModelIndex &index) const
    {
        if (!index.isValid())
            return 0;

        return Qt::ItemIsEditable | QAbstractItemModel::flags(index);
    }

    TreeItem *TreeModel::getItem(const QModelIndex &index) const
    {
        if (index.isValid()) {
            TreeItem *item = static_cast<TreeItem*>(index.internalPointer());
            if (item)
                return item;
        }
        return rootItem;
    }

    QVariant TreeModel::headerData(int section, Qt::Orientation orientation,
                                   int role) const
    {
        if (orientation == Qt::Horizontal && role == Qt::DisplayRole)
            return rootItem->data(section);

        return QVariant();
    }

    QModelIndex TreeModel::index(int row, int column, const QModelIndex &parent) const
    {
        if (parent.isValid() && parent.column() != 0)
            return QModelIndex();

        TreeItem *parentItem = getItem(parent);

        TreeItem *childItem = parentItem->child(row);
        if (childItem)
            return createIndex(row, column, childItem);
        else
            return QModelIndex();
    }

    bool TreeModel::insertColumns(int position, int columns, const QModelIndex &parent)
    {
        bool success;

        beginInsertColumns(parent, position, position + columns - 1);
        success = rootItem->insertColumns(position, columns);
        endInsertColumns();

        return success;
    }

    bool TreeModel::insertRows(int position, int rows, const QModelIndex &parent)
    {
        TreeItem *parentItem = getItem(parent);
        bool success;

        beginInsertRows(parent, position, position + rows - 1);
        success = parentItem->insertChildren(position, rows, rootItem->columnCount());
        endInsertRows();

        return success;
    }

    QModelIndex TreeModel::parent(const QModelIndex &index) const
    {
        if (!index.isValid())
            return QModelIndex();

        TreeItem *childItem = getItem(index);
        TreeItem *parentItem = childItem->parent();

        if (parentItem == rootItem)
            return QModelIndex();

        return createIndex(parentItem->childNumber(), 0, parentItem);
    }

    bool TreeModel::removeColumns(int position, int columns, const QModelIndex &parent)
    {
        bool success;

        beginRemoveColumns(parent, position, position + columns - 1);
        success = rootItem->removeColumns(position, columns);
        endRemoveColumns();

        if (rootItem->columnCount() == 0)
            removeRows(0, rowCount());

        return success;
    }

    bool TreeModel::removeRows(int position, int rows, const QModelIndex &parent)
    {
        TreeItem *parentItem = getItem(parent);
        bool success = true;

        beginRemoveRows(parent, position, position + rows - 1);
        success = parentItem->removeChildren(position, rows);
        endRemoveRows();

        return success;
    }

    int TreeModel::rowCount(const QModelIndex &parent) const
    {
        TreeItem *parentItem = getItem(parent);

        return parentItem->childCount();
    }

    bool TreeModel::setData(const QModelIndex &index, const QVariant &value, int role)
    {
        if (role != Qt::EditRole)
            return false;

        TreeItem *item = getItem(index);
        bool result = item->setData(index.column(), value);

        if (result)
            emit dataChanged(index, index);

        return result;
    }

    bool TreeModel::setHeaderData(int section, Qt::Orientation orientation,
                                  const QVariant &value, int role)
    {
        if (role != Qt::EditRole || orientation != Qt::Horizontal)
            return false;

        bool result = rootItem->setData(section, value);

        if (result)
            emit headerDataChanged(orientation, section, section);

        return result;
    }

    void TreeModel::setupModelData(const QStringList &lines, TreeItem *parent)
    {
        QList<TreeItem*> parents;
        QList<int> indentations;
        parents << parent;
        indentations << 0;

        int number = 0;

        while (number < lines.count()) {
            int position = 0;
            while (position < lines[number].length()) {
                if (lines[number].mid(position, 1) != " ")
                    break;
                ++position;
            }

            QString lineData = lines[number].mid(position).trimmed();

            if (!lineData.isEmpty()) {
                // Read the column data from the rest of the line.
                QStringList columnStrings = lineData.split("\t", QString::SkipEmptyParts);
                QVector<QVariant> columnData;
                for (int column = 0; column < columnStrings.count(); ++column)
                    columnData << columnStrings[column];

                if (position > indentations.last()) {
                    // The last child of the current parent is now the new parent
                    // unless the current parent has no children.

                    if (parents.last()->childCount() > 0) {
                        parents << parents.last()->child(parents.last()->childCount()-1);
                        indentations << position;
                    }
                } else {
                    while (position < indentations.last() && parents.count() > 0) {
                        parents.pop_back();
                        indentations.pop_back();
                    }
                }

                // Append a new item to the current parent's list of children.
                TreeItem *parent = parents.last();
                parent->insertChildren(parent->childCount(), 1, rootItem->columnCount());
                for (int column = 0; column < columnData.size(); ++column)
                    parent->child(parent->childCount() - 1)->setData(column, columnData[column]);
            }

            ++number;
        }
    }