HighScoreModel.qml Example File

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 import Qt 4.7

 // 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() }
 }