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 <QtWidgets>
 
#include "model.h"
 
DragDropListModel::DragDropListModel(const QStringList &strings,
                                     QObject *parent)
    : QStringListModel(strings, parent)
{
}
 
//! [0]
bool DragDropListModel::canDropMimeData(const QMimeData *data,
    Qt::DropAction action, int row, int column, const QModelIndex &parent) const
{
    Q_UNUSED(action);
    Q_UNUSED(row);
    Q_UNUSED(parent);
 
    if (!data->hasFormat("application/vnd.text.list"))
        return false;
 
    if (column > 0)
        return false;
 
    return true;
}
//! [0]
 
//! [1]
bool DragDropListModel::dropMimeData(const QMimeData *data,
    Qt::DropAction action, int row, int column, const QModelIndex &parent)
{
    if (!canDropMimeData(data, action, row, column, parent))
        return false;
 
    if (action == Qt::IgnoreAction)
        return true;
    //! [1]
 
    //! [2]
    int beginRow;
 
    if (row != -1)
        beginRow = row;
    //! [2] 
 
    //! [3]
    else if (parent.isValid())
        beginRow = parent.row();
    //! [3]
 
    //! [4]
    else
        beginRow = rowCount(QModelIndex());
    //! [4]
 
    //! [5]
    QByteArray encodedData = data->data("application/vnd.text.list");
    QDataStream stream(&encodedData, QIODevice::ReadOnly);
    QStringList newItems;
    int rows = 0;
 
    while (!stream.atEnd()) {
        QString text;
        stream >> text;
        newItems << text;
        ++rows;
    }
    //! [5]
 
//! [6]
    insertRows(beginRow, rows, QModelIndex());
    for (const QString &text : std::as_const(newItems)) {
        QModelIndex idx = index(beginRow, 0, QModelIndex());
        setData(idx, text);
        beginRow++;
    }
 
    return true;
}
//! [6]
 
//! [7]
Qt::ItemFlags DragDropListModel::flags(const QModelIndex &index) const
{
    Qt::ItemFlags defaultFlags = QStringListModel::flags(index);
 
    if (index.isValid())
        return Qt::ItemIsDragEnabled | Qt::ItemIsDropEnabled | defaultFlags;
    else
        return Qt::ItemIsDropEnabled | defaultFlags;
}
//! [7]
 
//! [8]
QMimeData *DragDropListModel::mimeData(const QModelIndexList &indexes) const
{
    QMimeData *mimeData = new QMimeData;
    QByteArray encodedData;
 
    QDataStream stream(&encodedData, QIODevice::WriteOnly);
 
    for (const QModelIndex &index : indexes) {
        if (index.isValid()) {
            QString text = data(index, Qt::DisplayRole).toString();
            stream << text;
        }
    }
 
    mimeData->setData("application/vnd.text.list", encodedData);
    return mimeData;
}
//! [8]
 
//! [9]
QStringList DragDropListModel::mimeTypes() const
{
    QStringList types;
    types << "application/vnd.text.list";
    return types;
}
//! [9]
 
//! [10]
Qt::DropActions DragDropListModel::supportedDropActions() const
{
    return Qt::CopyAction | Qt::MoveAction;
}
//! [10]