model.cpp Example File

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  #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;
  }