private slots:
    void onLegendMarkerClicked() {
        bool checked = false;
        qDebug() << "" << checked;
        QLegendMarker* marker = qobject_cast<QLegendMarker*>(sender());
        if (marker) {
            QLineSeries* series = qobject_cast<QLineSeries*>(marker->series());
            if (series) {
                if (series->isVisible())
                {
                    series->setVisible(false);
                }
                else 
                {
                    series->setVisible(true);
                }
                
            }
            marker->setVisible(true);
        }
    }

// 连接图例标记的点击事件
for (QLegendMarker* marker : chart->legend()->markers()) {
    qDebug()<<""<<marker->series()->name();
    connect(marker, SIGNAL(clicked()), this, SLOT(onLegendMarkerClicked()));
}