HighScoreModel.qml Example File

demos/declarative/snake/qml/snake/content/HighScoreModel.qml
/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the QtDeclarative module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** As a special exception, The Qt Company gives you certain additional
** rights. These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

import QtQuick 1.0

// Models a high score table.
//
// Use this component like this:
//
//  HighScoreModel {
//      id: highScores
//      game: "MyCoolGame"
//  }
//
// Then use either use the top-score properties:
//
//  Text { text: "HI: " + highScores.topScore }
//
// or, use the model in a view:
//
//  ListView {
//      model: highScore
//      delegate: Component {
//                    ... player ... score ...
//                }
//  }
//
// Add new scores via:
//
//  saveScore(newScore)
//
// or:
//
//  savePlayerScore(playerName,newScore)
//
// The best maxScore scores added by this method will be retained in an SQL database,
// and presented in the model and in the topScore/topPlayer properties.
//

ListModel {
    id: model
    property string game: ""
    property int topScore: 0
    property string topPlayer: ""
    property int maxScores: 10

    function __db()
    {
        return openDatabaseSync("HighScoreModel", "1.0", "Generic High Score Functionality for QML", 1000000);
    }
    function __ensureTables(tx)
    {
        tx.executeSql('CREATE TABLE IF NOT EXISTS HighScores(game TEXT, score INT, player TEXT)', []);
    }

    function fillModel() {
        __db().transaction(
            function(tx) {
                __ensureTables(tx);
                var rs = tx.executeSql("SELECT score,player FROM HighScores WHERE game=? ORDER BY score DESC", [game]);
                model.clear();
                if (rs.rows.length > 0) {
                    topScore = rs.rows.item(0).score
                    topPlayer = rs.rows.item(0).player
                    for (var i=0; i<rs.rows.length; ++i) {
                        if (i < maxScores)
                            model.append(rs.rows.item(i))
                    }
                    if (rs.rows.length > maxScores)
                        tx.executeSql("DELETE FROM HighScores WHERE game=? AND score <= ?",
                                            [game, rs.rows.item(maxScores).score]);
                }
            }
        )
    }

    function savePlayerScore(player,score) {
        __db().transaction(
            function(tx) {
                __ensureTables(tx);
                tx.executeSql("INSERT INTO HighScores VALUES(?,?,?)", [game,score,player]);
                fillModel();
            }
        )
    }

    function saveScore(score) {
        savePlayerScore("player",score);
    }

    function clearScores() {
        __db().transaction(
            function(tx) {
                tx.executeSql("DELETE FROM HighScores WHERE game=?", [game]);
                fillModel();
            }
        )
    }

    Component.onCompleted: { fillModel() }
}

© 2016 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.