model.cpp Example File | Qt Widgets 5.12.8

Qt 5.12 | Qt Widgets | Interview | model.cpp Example File

Qt 5.12.8 Reference Documentation

# model.cpp Example File

itemviews/interview/model.cpp

      /****************************************************************************
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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;
      }