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# treemodel.cpp Example File
itemviews/editabletreemodel/treemodel.cpp

     /****************************************************************************
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     ** Contact: Qt Software Information (qt-info@nokia.com)
     **
     ** This file is part of the examples of the Qt Toolkit.
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     ** accordance with the Qt Commercial License Agreement provided with the
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     ** Alternatively, this file may be used under the terms of the GNU Lesser
     ** General Public License version 2.1 as published by the Free Software
     ** Foundation and appearing in the file LICENSE.LGPL included in the
     ** packaging of this file.  Please review the following information to
     ** ensure the GNU Lesser General Public License version 2.1 requirements
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     ** GNU General Public License Usage
     ** Alternatively, this file may be used under the terms of the GNU
     ** General Public License version 3.0 as published by the Free Software
     ** Foundation and appearing in the file LICENSE.GPL included in the
     ** packaging of this file.  Please review the following information to
     ** ensure the GNU General Public License version 3.0 requirements will be
     ** met: http://www.gnu.org/copyleft/gpl.html.
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     #include <QtGui>

     #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 | Qt::ItemIsEnabled | Qt::ItemIsSelectable;
     }

     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++;
         }
     }