Repaint QSplineSeries

Hello!

I would like dynamically rewrite chart, generated by QSplineSeries.
I am trying to achieve it this way:

Code:

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QSplineSeries* series_for_Vy= new QSplineSeries();
     QChart* chart_for_Vy = new QChart();
QGroupBox *Widget::set_splinechart_Vy()
{
 
    int n ; //номер шага по времени
    number_of_step_for_Vy = new QLineEdit("steps");
 
    series_for_Vy->append(3,3);
    series_for_Vy->append(2,5);
 
    chart_for_Vy->legend()->hide();
    chart_for_Vy->addSeries( series_for_Vy);
    chart_for_Vy->setTitle("Vy (N)");
    chart_for_Vy->createDefaultAxes();
    chart_for_Vy->axisY()->setRange(0,  10);
    chart_for_Vy->axisX()->setRange(0,10);
    chart_for_Vy->axisX()->setTitleText("Number of Node, N");
    chart_for_Vy->axisY()->setTitleText("Velocity, Vy");
 
 
 
        QChartView *chartView = new QChartView(chart_for_Vy);
 
 
    slider_for_Vy = new QSlider(Qt::Orientation::Horizontal);
    slider_for_Vy->setRange(1,999);
 
 
    QVBoxLayout *vert = new QVBoxLayout;
    QHBoxLayout *horiz = new QHBoxLayout;
    vert->addWidget(chartView);
   // vert->addWidget(slider);
    horiz->addWidget(slider_for_Vy,Qt::AlignLeft);horiz->addWidget(number_of_step_for_Vy);
    vert->addLayout(horiz);
    QGroupBox* groupbox = new QGroupBox("Y-component of velocity");
    groupbox->setLayout(vert);
    //connect(number_of_step_for_Vy,SIGNAL(textEdited(QString)),SLOT(update()));
    return groupbox;
}
 
void Widget::plot_Velocity_Y()
{
    series_for_Vy->clear();
    series_for_Vy->append(3,3);
    series_for_Vy->append(2,9);
    chart_for_Vy->clearFocus();
    chart_for_Vy->addSeries( series_for_Vy);
 
}

---

But when program comes to SLOT plot_Velocity_Y, it does not change and lines appear:
"Can not add series. Series already on the chart."

How to handle this?

You're trying to add the same series more than once (that is, QSplineSeries * series_for_Vy has already been added to the chart). The fact that you changed the data in the series makes no difference.

You probably need to do this:

- remove the series from the chart (QChart::removeSeries())
- change the series data
- add the series back to the chart (QChart::addSeries())

You may not actually need to remove and add the series, but from what I remember of QChart, changing the data in the series may not result in an update to the chart.

Thank you!

I'm using QML for my charts, but I have been able to achieve updating the series without removing and recreating it...

Code:

---

wavgSeries.remove(0);
            wavgSeries.append(appWin.wxMsec,appWin.wxWavg);

---

Basically, removing the first element in the series, then just appending a new one...

--SamG