QLegendMarker signal/slot connect not working

diego-qt

Hello, I am trying to make a chart where the user can hide and show the available line series by clicking the respective legend marker, like this:

    QList<QLineSeries*> lineSeries;
    for(int i = 0; i < nbCharts; i++)
    {
        QLineSeries *series = new QLineSeries;
        lineSeries.append(series);
        chart->addSeries(series);
        series->attachAxis(axisX);
        series->attachAxis(axisY);
        QLegendMarker *marker = chart->legend()->markers(series)[0];
        marker->setLabel(QString::number(i));
        connect(marker, SIGNAL(clicked()), this, SLOT(markerClicked()));
        connect(marker, SIGNAL(hovered(bool)), this, SLOT(markerHovered(bool)));
    }

However, this doesn't seem to work and I don't understand why. I have the two slot functions in the public slots section in header file, I have no error notifications regarding the connect when debugging and when I put qDebug << before the connect lines, the debugger gives me true.

I tried the code in the example in https://doc.qt.io/archives/qt-5.7/qtcharts-legendmarkers-example.html like this:

    for(int i = 0; i < nbCharts; i++)
    {
        QLineSeries *series = new QLineSeries;
        lineSeries.append(series);
        chart->addSeries(series);
        series->attachAxis(axisX);
        series->attachAxis(axisY);
        QLegendMarker *marker = chart->legend()->markers(series)[0];
        marker->setLabel(QString::number(i));
    }
    const auto markers = chart->legend()->markers();
    for (QLegendMarker *marker : markers) {
        connect(marker, SIGNAL(clicked()), this, SLOT(markerClicked()));
        connect(marker, SIGNAL(hovered(bool)), this, SLOT(markerHovered(bool)));
    }

but it hasn't worked either. Any ideas why this doesn't work?

Edit: the chart works fine. I am able to add points to the series and print them in the chart and do other things. It's just the connect that doesn't seem to work.

diego-qt

I made a QPushButton that would simulate clicking the QLegendMarker with a connect:

    QPushButton *butt = new QPushButton("activate marker0");
    QLegendMarker *marker = chart->legend()->markers()[0];
    connect(butt, &QPushButton::clicked, marker, &QLegendMarker::clicked);
    butt->show();

This actually worked and I can see the first line series disappear and reappear with the click of the button.
I realized that I did override the mousePressEvent, mouseMoveEvent and mouseReleaseEvent functions of the class (which inherits from QChartView), so could this mean that I can't override these functions AND use the clicked and hovered signals from QLegendMarker?

Christian Ehrlicher

@diego-qt said in QLegendMarker signal/slot connect not working:

so could this mean that I can't override these functions AND use the clicked and hovered signals from QLegendMarker?

You can but when you override a function you should call the base class when you want it's functionality.

diego-qt

Yes, I added QChartView::mousePressEvent(event) (and the other two) at the end of the respective overriden functions and it works now.