treemodel.cpp Example File

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  #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].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);
              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;
      }
  }