- Qt 5.5
- Qt Widgets
- Item Views Puzzle Example
- piecesmodel.cpp Example File
- Qt 5.5.1 Reference Documentation

# piecesmodel.cpp Example File

itemviews/puzzle/piecesmodel.cpp

    /****************************************************************************
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    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** This file is part of the examples of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
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    #include "piecesmodel.h"

    #include <QIcon>
    #include <QMimeData>

    PiecesModel::PiecesModel(int pieceSize, QObject *parent)
        : QAbstractListModel(parent), m_PieceSize(pieceSize)
    {
    }

    QVariant PiecesModel::data(const QModelIndex &index, int role) const
    {
        if (!index.isValid())
            return QVariant();

        if (role == Qt::DecorationRole)
            return QIcon(pixmaps.value(index.row()).scaled(m_PieceSize, m_PieceSize,
                             Qt::KeepAspectRatio, Qt::SmoothTransformation));
        else if (role == Qt::UserRole)
            return pixmaps.value(index.row());
        else if (role == Qt::UserRole + 1)
            return locations.value(index.row());

        return QVariant();
    }

    void PiecesModel::addPiece(const QPixmap &pixmap, const QPoint &location)
    {
        int row;
        if (int(2.0 * qrand() / (RAND_MAX + 1.0)) == 1)
            row = 0;
        else
            row = pixmaps.size();

        beginInsertRows(QModelIndex(), row, row);
        pixmaps.insert(row, pixmap);
        locations.insert(row, location);
        endInsertRows();
    }

    Qt::ItemFlags PiecesModel::flags(const QModelIndex &index) const
    {
        if (index.isValid())
            return (QAbstractListModel::flags(index)|Qt::ItemIsDragEnabled);

        return Qt::ItemIsDropEnabled;
    }

    bool PiecesModel::removeRows(int row, int count, const QModelIndex &parent)
    {
        if (parent.isValid())
            return false;

        if (row >= pixmaps.size() || row + count <= 0)
            return false;

        int beginRow = qMax(0, row);
        int endRow = qMin(row + count - 1, pixmaps.size() - 1);

        beginRemoveRows(parent, beginRow, endRow);

        while (beginRow <= endRow) {
            pixmaps.removeAt(beginRow);
            locations.removeAt(beginRow);
            ++beginRow;
        }

        endRemoveRows();
        return true;
    }

    QStringList PiecesModel::mimeTypes() const
    {
        QStringList types;
        types << "image/x-puzzle-piece";
        return types;
    }

    QMimeData *PiecesModel::mimeData(const QModelIndexList &indexes) const
    {
        QMimeData *mimeData = new QMimeData();
        QByteArray encodedData;

        QDataStream stream(&encodedData, QIODevice::WriteOnly);

        foreach (QModelIndex index, indexes) {
            if (index.isValid()) {
                QPixmap pixmap = qvariant_cast<QPixmap>(data(index, Qt::UserRole));
                QPoint location = data(index, Qt::UserRole+1).toPoint();
                stream << pixmap << location;
            }
        }

        mimeData->setData("image/x-puzzle-piece", encodedData);
        return mimeData;
    }

    bool PiecesModel::dropMimeData(const QMimeData *data, Qt::DropAction action,
                                   int row, int column, const QModelIndex &parent)
    {
        if (!data->hasFormat("image/x-puzzle-piece"))
            return false;

        if (action == Qt::IgnoreAction)
            return true;

        if (column > 0)
            return false;

        int endRow;

        if (!parent.isValid()) {
            if (row < 0)
                endRow = pixmaps.size();
            else
                endRow = qMin(row, pixmaps.size());
        } else {
            endRow = parent.row();
        }

        QByteArray encodedData = data->data("image/x-puzzle-piece");
        QDataStream stream(&encodedData, QIODevice::ReadOnly);

        while (!stream.atEnd()) {
            QPixmap pixmap;
            QPoint location;
            stream >> pixmap >> location;

            beginInsertRows(QModelIndex(), endRow, endRow);
            pixmaps.insert(endRow, pixmap);
            locations.insert(endRow, location);
            endInsertRows();

            ++endRow;
        }

        return true;
    }

    int PiecesModel::rowCount(const QModelIndex &parent) const
    {
        if (parent.isValid())
            return 0;
        else
            return pixmaps.size();
    }

    Qt::DropActions PiecesModel::supportedDropActions() const
    {
        return Qt::CopyAction | Qt::MoveAction;
    }

    void PiecesModel::addPieces(const QPixmap& pixmap)
    {
        beginRemoveRows(QModelIndex(), 0, 24);
        pixmaps.clear();
        locations.clear();
        endRemoveRows();
        for (int y = 0; y < 5; ++y) {
            for (int x = 0; x < 5; ++x) {
                QPixmap pieceImage = pixmap.copy(x*m_PieceSize, y*m_PieceSize, m_PieceSize, m_PieceSize);
                addPiece(pieceImage, QPoint(x, y));
            }
        }
    }