如何使用QMouseEvent在QChart中显示鼠标位置？

Question

我对Qt和C++非常陌生。我有一个QChart，它有一个QLineSeries对象。我想向用户展示鼠标在坐标系上的投影。我的问题是，除了我的QChart对象之外，我可以在任何地方显示坐标。我只想在鼠标在QChart时显示坐标。下面是我的代码示例：

boxWhisker.h文件

QGraphicsSimpleTextItem *m_coordX;
QGraphicsSimpleTextItem *m_coordY;
QChart *chartTrendLine;
QChartView *trendLineChartView;
QLineSeries *trendLine;

boxWhisker.cpp文件

this->chartTrendLine = new QChart();
this->chartTrendLine->addSeries(this->trendLine);
this->chartTrendLine->legend()->setVisible(true);
this->chartTrendLine->createDefaultAxes();
this->chartTrendLine->setAcceptHoverEvents(true);

this->trendLineChartView = new QChartView(this->chartTrendLine);
this->trendLineChartView->setRenderHint(QPainter::Antialiasing);

this->m_coordX = new QGraphicsSimpleTextItem(this->chartTrendLine);
this->m_coordX->setPos(this->chartTrendLine->size().width()/2+50,this->chartTrendLine->size().height());

this->m_coordY = new QGraphicsSimpleTextItem(this->chartTrendLine);
this->m_coordY->setPos(this->chartTrendLine->size().width()/2+100,this->chartTrendLine->size().height());

void boxWhiskerDialog::mouseMoveEvent(QMouseEvent *mouseEvent)
{
this->m_coordY->setText(QString("Y: %1").arg(this->chartTrendLine->mapToValue(mouseEvent->pos()).y()));
this->m_coordX->setText(QString("X: %1").arg(this->chartTrendLine->mapToValue(mouseEvent->pos()).x()));
}

我的问题是如何只在QChart上显示坐标？任何帮助都将是徒劳无功的谢谢！

编辑

在这里，我尝试创建一个由QChart类继承的新类，并在我的新类中定义我的mouseEvent函数。下面是我的代码示例：

qchart_me.h：

class QChart_ME : public QT_CHARTS_NAMESPACE::QChart
{
public:
    QChart_ME();

protected:
    void mouseMoveEvent(QGraphicsSceneMouseEvent *event);

private:
    QGraphicsSimpleTextItem *m_coordX;
    QGraphicsSimpleTextItem *m_coordY;
    QChart *m_chart;

};

qchart_me.cpp：

QChart_ME::QChart_ME()
{

}

void QChart_ME::mouseMoveEvent(QGraphicsSceneMouseEvent *Myevent)
{
    m_coordX->setText(QString("X: %1").arg(m_chart->mapToValue(Myevent->pos()).x()));
    m_coordY->setText(QString("Y: %1").arg(m_chart->mapToValue(Myevent->pos()).y()));

}

盒语h：

QChart_ME *chartTrendLine; 

boxWhisker.cpp

this->chartTrendLine = new QChart_ME();
this->chartTrendLine->addSeries(this->trendLine);
this->chartTrendLine->legend()->setVisible(true);
this->chartTrendLine->createDefaultAxes();
this->chartTrendLine->setAcceptHoverEvents(true);

QGraphicsSceneMouseEvent *myEvent;

this->chartTrendLine->mouseMoveEvent(myEvent);

我试图像Qt标注示例那样编辑我的代码。

我得到的错误：‘虚拟空QChart_ME::mouseMoveEvent(QGraphicsSceneMouseEvent*)’在这个上下文this->chartTrendLine->mouseMoveEvent(myEvent)；中受到保护

我怎样才能解决这个问题？

Answer 1

原因

您正在为您的boxWhiskerDialog类而不是为QChart获取鼠标事件。

解决方案

子类QChart并重新实现其mouseMoveEvent，而不是重新实现boxWhiskerDialog::mouseMoveEvent。