treemodel.cpp Example File

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  /*
      treemodel.cpp

      Provides a simple tree model to show how to create and use hierarchical
      models.
  */

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

  #include <QStringList>

  TreeModel::TreeModel(const QString &data, QObject *parent)
      : QAbstractItemModel(parent)
  {
      QList<QVariant> rootData;
      rootData << "Title" << "Summary";
      rootItem = new TreeItem(rootData);
      setupModelData(data.split(QString("\n")), rootItem);
  }

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

  int TreeModel::columnCount(const QModelIndex &parent) const
  {
      if (parent.isValid())
          return static_cast<TreeItem*>(parent.internalPointer())->columnCount();
      else
          return rootItem->columnCount();
  }

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

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

      TreeItem *item = static_cast<TreeItem*>(index.internalPointer());

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

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

      return QAbstractItemModel::flags(index);
  }

  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 (!hasIndex(row, column, parent))
          return QModelIndex();

      TreeItem *parentItem;

      if (!parent.isValid())
          parentItem = rootItem;
      else
          parentItem = static_cast<TreeItem*>(parent.internalPointer());

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

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

      TreeItem *childItem = static_cast<TreeItem*>(index.internalPointer());
      TreeItem *parentItem = childItem->parentItem();

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

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

  int TreeModel::rowCount(const QModelIndex &parent) const
  {
      TreeItem *parentItem;
      if (parent.column() > 0)
          return 0;

      if (!parent.isValid())
          parentItem = rootItem;
      else
          parentItem = static_cast<TreeItem*>(parent.internalPointer());

      return parentItem->childCount();
  }

  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].at(position) != ' ')
                  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);
              QList<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.
              parents.last()->appendChild(new TreeItem(columnData, parents.last()));
          }

          ++number;
      }
  }