调用'QtCharts::QLineSeries::append(int&，Date&)没有匹配的函数

Question

m_total_hour_series->append(pair.first, pair.second);这一行是问题的根源。错误消息显示:没有匹配的函数用于调用'QtCharts::QLineSeries::append(int&，Date&)‘

我已经查看了折线图的示例，并查找了附加的日期数据，但都无济于事。

我正在尝试从数据库中的数据制作折线图。我正在传递该系列的值的对列表。我的window.cpp文件具有以下变量：

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;

我的model.cpp文件包含以下代码：

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);
}

我的window.cpp文件包含以下代码：

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);
}

谢谢你的帮助。

Answer 1

我在QDateTimeAxis上搜索过。答案是使用.toMSecsSinceEpoch()。这是站点: doc.qt.io/qt-/qdatetimeaxis.html