model.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
 
/*
  model.cpp
 
  A simple model that uses a QStringList as its data source.
*/
 
#include "model.h"
 
/*!
    Returns the number of items in the string list as the number of rows
    in the model.
*/
 
//! [0]
int StringListModel::rowCount(const QModelIndex &parent) const
{
    return stringList.count();
}
//! [0]
 
 
#if 0
// This represents a read-only version of data(), an early stage in the
// development of the example leading to an editable StringListModel.
 
/*!
    Returns an appropriate value for the requested data.
    If the view requests an invalid index, an invalid variant is returned.
    Any valid index that corresponds to a string in the list causes that
    string to be returned.
*/
 
//! [1-data-read-only]
QVariant StringListModel::data(const QModelIndex &index, int role) const
{
    if (!index.isValid())
        return QVariant();
 
    if (index.row() >= stringList.size())
        return QVariant();
 
    if (role == Qt::DisplayRole)
        return stringList.at(index.row());
    else
        return QVariant();
}
//! [1-data-read-only]
#endif
 
 
/*!
    Returns an appropriate value for the requested data.
    If the view requests an invalid index, an invalid variant is returned.
    Any valid index that corresponds to a string in the list causes that
    string to be returned.
*/
 
//! [1]
QVariant StringListModel::data(const QModelIndex &index, int role) const
{
    if (!index.isValid())
        return QVariant();
 
    if (index.row() >= stringList.size())
        return QVariant();
 
    if (role == Qt::DisplayRole || role == Qt::EditRole)
        return stringList.at(index.row());
    else
        return QVariant();
}
//! [1]
 
/*!
    Returns the appropriate header string depending on the orientation of
    the header and the section. If anything other than the display role is
    requested, we return an invalid variant.
*/
 
//! [2]
QVariant StringListModel::headerData(int section, Qt::Orientation orientation,
                                     int role) const
{
    if (role != Qt::DisplayRole)
        return QVariant();
 
    if (orientation == Qt::Horizontal)
        return QStringLiteral("Column %1").arg(section);
    else
        return QStringLiteral("Row %1").arg(section);
}
//! [2]
 
/*!
    Returns an appropriate value for the item's flags. Valid items are
    enabled, selectable, and editable.
*/
 
//! [3]
Qt::ItemFlags StringListModel::flags(const QModelIndex &index) const
{
    if (!index.isValid())
        return Qt::ItemIsEnabled;
 
    return QAbstractItemModel::flags(index) | Qt::ItemIsEditable;
}
//! [3]
 
/*!
    Changes an item in the string list, but only if the following conditions
    are met:
 
    * The index supplied is valid.
    * The index corresponds to an item to be shown in a view.
    * The role associated with editing text is specified.
 
    The dataChanged() signal is emitted if the item is changed.
*/
 
//! [4]
bool StringListModel::setData(const QModelIndex &index,
                              const QVariant &value, int role)
{
    if (index.isValid() && role == Qt::EditRole) {
 
        stringList.replace(index.row(), value.toString());
        emit dataChanged(index, index, {role});
        return true;
    }
//! [4] //! [5]
    return false;
}
//! [5]
 
/*!
    Inserts a number of rows into the model at the specified position.
*/
 
//! [6]
bool StringListModel::insertRows(int position, int rows, const QModelIndex &parent)
{
    beginInsertRows(QModelIndex(), position, position+rows-1);
 
    for (int row = 0; row < rows; ++row) {
        stringList.insert(position, "");
    }
 
    endInsertRows();
    return true;
//! [6] //! [7]
}
//! [7]
 
/*!
    Removes a number of rows from the model at the specified position.
*/
 
//! [8]
bool StringListModel::removeRows(int position, int rows, const QModelIndex &parent)
{
    beginRemoveRows(QModelIndex(), position, position+rows-1);
 
    for (int row = 0; row < rows; ++row) {
        stringList.removeAt(position);
    }
 
    endRemoveRows();
    return true;
//! [8] //! [9]
}
//! [9]