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The line m_total_hour_series->append(pair.first, pair.second); is the source of the problem. The error message says: No matching function for call to 'QtCharts::QLineSeries::append(int&,Date&)'

I have looked at examples of the line chart and looked for appending date data, to no avail.

I am trying to make a line chart from data in the database. I am passing a list of pairs for values for the series. My window.cpp file has the following variables:

QLineSeries* m_total_hour_series;
QChart* m_total_hour_chart;
QDateTimeAxis* m_total_hour_axis_x;
QValueAxis* m_total_hour_axis_y;
QChartView* m_total_hour_chart_view;

My model.cpp file contains the following code:

QList<QPair<int,QDateTime>> ScannerModel::GetTotalHourSeries()
{
    QList<QPair<int,QDateTime>> total_hour_series;
    QString query_string;
    QDateTime intervals;
    QSqlDatabase db = QSqlDatabase::database(m_database_connection);
    QList<QPair<int,QDateTime>> graph_point;

    query_string =  QString("SELECT COUNT(BagId) AS num_bags, ");
    query_string += QString("   sec_to_time(time_to_sec(ScannedOn) - time_to_sec(ScannedOn)%(15*60)) AS intervals ");
    query_string += QString("FROM Bag ");
    query_string += QString("WHERE ScannedOn > date_sub(now(), INTERVAL 3 HOUR) ");
    query_string += QString("GROUP BY intervals ");

    QSqlQuery query(query_string, db);

    if (query.size() > 0)
    {
        while (query.next())
        {
            graph_point.first = query.value(0).toInt();
            intervals = query.value(1).toDateTime();
            intervals.addSecs(m_time_zone.offsetFromUtc(intervals));
            graph_point.second = intervals;
            total_hour_series->append(graph_point);
         }
        qApp->processEvents();
    }
    return (total_hour_series);
}

My window.cpp file contains the following code:

void ScannerWindow::UpdateChartTotalHour()
{
    QList<QPair<int,QDateTime>> listOfPairs;
    m_total_hour_series->clear();

    listOfPairs = m_model->GetTotalHourSeries();
    for (int i = 0; i < listOfPairs.size(); i++)
    {
        QPair<int, QDateTime> pair = listOfPairs.at(i);
        m_total_hour_series->append(pair.first, pair.second);
    }
    m_total_hour_chart->addSeries(m_total_hour_series);
    qApp->processEvents();

    m_total_hour_axis_x->setTickCount(12);
    m_total_hour_axis_x->setFormat("HH:mm");
    m_total_hour_chart->addAxis(m_total_hour_axis_x, Qt::AlignBottom);
    m_total_hour_series->attachAxis(m_total_hour_axis_x);

    m_total_hour_axis_y->setLabelFormat("%i");
    m_total_hour_chart->addAxis(m_total_hour_axis_y, Qt::AlignLeft);
    m_total_hour_series->attachAxis(m_total_hour_axis_y);
}

Thank you for your help.

Debra
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  • `append` seems to only take two `real`s or a `QPointF`: https://doc.qt.io/qt-5/qlineseries-members.html – Alan Birtles Mar 17 '20 at 18:20
  • Looks like it only takes doubles or a custom class. https://doc.qt.io/qt-5/qxyseries.html#append-1 – Taekahn Mar 17 '20 at 18:23
  • Yes, it seems that append only takes reals, but the x-axis is a QDateTime (QDateTimeAxis* m_total_hour_axis_x;), so there has to be a way to put a QDateTime into the x value of the point. Maybe there is something other than append for this? – Debra Mar 17 '20 at 20:45

1 Answers1

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I searched on QDateTimeAxis. The answer is to use .toMSecsSinceEpoch(). Here is the site: doc.qt.io/qt-/qdatetimeaxis.html

Debra
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