model.cpp Example File

 /****************************************************************************
 **
 ** Copyright (C) 2016 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the demonstration applications of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:BSD$
 ** Commercial License Usage
 ** Licensees holding valid commercial Qt licenses may use this file in
 ** accordance with the commercial license agreement provided with the
 ** Software or, alternatively, in accordance with the terms contained in
 ** a written agreement between you and The Qt Company. For licensing terms
 ** and conditions see https://www.qt.io/terms-conditions. For further
 ** information use the contact form at https://www.qt.io/contact-us.
 **
 ** BSD License Usage
 ** Alternatively, 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 "model.h"

 #include <QIcon>
 #include <QPixmap>

 Model::Model(int rows, int columns, QObject *parent)
     : QAbstractItemModel(parent),
       services(QPixmap(":/images/services.png")),
       rc(rows), cc(columns),
       tree(new QVector<Node>(rows, Node(0)))
 {

 }

 Model::~Model()
 {
     delete tree;
 }

 QModelIndex Model::index(int row, int column, const QModelIndex &parent) const
 {
     if (row < rc && row >= 0 && column < cc && column >= 0) {
         Node *parentNode = static_cast<Node*>(parent.internalPointer());
         Node *childNode = node(row, parentNode);
         if (childNode)
             return createIndex(row, column, childNode);
     }
     return QModelIndex();
 }

 QModelIndex Model::parent(const QModelIndex &child) const
 {
     if (child.isValid()) {
         Node *childNode = static_cast<Node*>(child.internalPointer());
         Node *parentNode = parent(childNode);
         if (parentNode)
             return createIndex(row(parentNode), 0, parentNode);
     }
     return QModelIndex();
 }

 int Model::rowCount(const QModelIndex &parent) const
 {
     return (parent.isValid() && parent.column() != 0) ? 0 : rc;
 }

 int Model::columnCount(const QModelIndex &parent) const
 {
     Q_UNUSED(parent);
     return cc;
 }

 QVariant Model::data(const QModelIndex &index, int role) const
 {
     if (!index.isValid())
         return QVariant();
     if (role == Qt::DisplayRole)
         return QVariant("Item " + QString::number(index.row()) + ':' + QString::number(index.column()));
     if (role == Qt::DecorationRole) {
         if (index.column() == 0)
             return iconProvider.icon(QFileIconProvider::Folder);
         return iconProvider.icon(QFileIconProvider::File);
     }
     return QVariant();
 }

 QVariant Model::headerData(int section, Qt::Orientation orientation, int role) const
 {
     if (role == Qt::DisplayRole)
         return QString::number(section);
     if (role == Qt::DecorationRole)
         return QVariant::fromValue(services);
     return QAbstractItemModel::headerData(section, orientation, role);
 }

 bool Model::hasChildren(const QModelIndex &parent) const
 {
     if (parent.isValid() && parent.column() != 0)
         return false;
     return rc > 0 && cc > 0;
 }

 Qt::ItemFlags Model::flags(const QModelIndex &index) const
 {
     if (!index.isValid())
         return 0;
     return Qt::ItemIsDragEnabled|QAbstractItemModel::flags(index);
 }

 Model::Node *Model::node(int row, Node *parent) const
 {
     if (parent && !parent->children)
         parent->children = new QVector<Node>(rc, Node(parent));
     QVector<Node> *v = parent ? parent->children : tree;
     return const_cast<Node*>(&(v->at(row)));
 }

 Model::Node *Model::parent(Node *child) const
 {
     return child ? child->parent : 0;
 }

 int Model::row(Node *node) const
 {
     const Node *first = node->parent ? &(node->parent->children->at(0)) : &(tree->at(0));
     return node - first;
 }