qt-everywhere-src-5.15.1/qtdoc/examples/demos/stocqt/content/StockModel.qml

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import QtQuick 2.0

ListModel {
    id: model
    property string stockId: ""
    property string stockName: ""
    property var newest
    property var oldest
    property bool ready: false
    property real stockPrice: 0.0
    property real stockPriceChanged: 0.0

    signal dataReady

    function indexOf(date) {
        if (model.count == 0)
            return -1;

        if (newest <= date)
            date = new Date(newest.getYear(),
                            newest.getMonth(),
                            newest.getDate() - 7);

        if (oldest >= date)
            return model.count - 1;

        var currDiff = 0;
        var bestDiff = Math.abs(date.getTime() - newest.getTime());
        var retval = 0;
        for (var i = 0; i < model.count; i++) {
            var d = new Date(model.get(i).date);
            currDiff = Math.abs(d.getTime() - date.getTime());
            if (currDiff < bestDiff) {
                bestDiff = currDiff;
                retval = i + 1;
            }
            if (currDiff > bestDiff)
                return retval;
        }
        return -1;
    }

    function createStockPrice(r) {
        return {
                "date": r[0],
                "open":r[1],
                "high":r[2],
                "low":r[3],
                "close":r[4],
                "volume":r[5],
               };
    }

    function updateStock() {
        if (stockId === "")
            return;

        var startDate = new Date(2011, 4, 25);
        var endDate = new Date(); //today

        var req = "data/" + stockId + ".csv"
        if (!req)
            return;

        var xhr = new XMLHttpRequest;

        xhr.open("GET", req, true);

        model.ready = false;
        model.clear();
        var i = 1; //skip the first line
        xhr.onreadystatechange = function() {
            if (xhr.readyState === XMLHttpRequest.LOADING || xhr.readyState === XMLHttpRequest.DONE) {
                var records = xhr.responseText.split('\n');
                for (;i < records.length; i++ ) {
                    var r = records[i].split(',');
                    if (r.length >= 6)
                        model.append(createStockPrice(r));
                }

                if (xhr.readyState === XMLHttpRequest.DONE) {
                    if (model.count > 0) {
                        model.ready = true;
                        model.stockPrice = model.get(0).close;
                        model.stockPriceChanged = model.count > 1 ? (Math.round((model.stockPrice - model.get(1).close) * 100) / 100) : 0;
                        newest = new Date(model.get(0).date);
                        oldest = new Date(model.get(model.count - 1).date);
                    } else {
                        model.stockPrice = 0;
                        model.stockPriceChanged = 0;
                    }
                    model.dataReady(); // emit signal - model.ready indicates whether the data is valid
                }
            }
        }
        xhr.send()
    }
}