treemodel.cpp Example File | Qt Widgets 5.12.8

Qt 5.12 | Qt Widgets | Editable Tree Model Example | treemodel.cpp Example File

Qt 5.12.8 Reference Documentation

# treemodel.cpp Example File

itemviews/editabletreemodel/treemodel.cpp

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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, {role});

          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;
          }
      }