QT 无法通过上下文菜单添加新绘图 (QCustomPlot)

Question

我正在尝试使用上下文菜单将新的sub-axes图添加到现有的qcustomplot小部件中。如果我在类构造函数中调用我的_addGraph函数，它会按预期工作。但是如果我将其用作slot，图形不会添加到绘图中。

在调试中，我看到函数调用并且它按预期工作，但没有添加新图。

#pragma once
#include <QWidget>
#include <QVBoxLayout>
#include "qcustomplot.h"
#include "menu_NewGraph.h"
class w_SignalTab : public QWidget
{
Q_OBJECT
private:
struct t_Plot
{
QCPLayoutGrid* p_layout;
QCPAxisRect *p_axisrect;
};
public:
w_SignalTab(unsigned int msg, unsigned int dev, QString name)
{
setLayout(&_wl);
_cplot.plotLayout()->clear();
_cplot.setContextMenuPolicy(Qt::CustomContextMenu);
connect(&_cplot, SIGNAL(customContextMenuRequested(QPoint)), 
this, SLOT(_contextMenuRequest(QPoint)));
_wl.addWidget(&_cplot);
setContextMenuPolicy(Qt::CustomContextMenu);
connect(this, SIGNAL(customContextMenuRequested(QPoint)), 
this, SLOT(_contextMenuRequest(QPoint)));
//!!! this slot is not work
connect(&_menuNewGraph, SIGNAL(addGraph(QString, int, int)), 
this, SLOT(_addGraph(QString, int, int)));
_addGraph(" ", 0, 0);   // this works fine
};
~w_SignalTab(){};
private slots:
void _contextMenuRequest(QPoint pos)
{
QWidget* obj_sender = qobject_cast<QWidget*>(sender());
QMenu menu;
menu.addAction("Add Plot", this, SLOT(_addGraphMenu()));
menu.exec(obj_sender->mapToGlobal(pos));
};
void _addGraphMenu() 
{ 
_menuNewGraph.show(); 
}
// this work only in constructor
void _addGraph(QString name, int bits_from, int bits_to)
{
t_Plot pl;
pl.p_layout = new QCPLayoutGrid;
pl.p_axisrect = new QCPAxisRect(&_cplot/*, false*/);
pl.p_layout->addElement(0, 0, pl.p_axisrect);
_cplot.plotLayout()->addElement(_plots.count(), 0, pl.p_layout);
_plots.append(pl);
}
private:
QVBoxLayout _wl;
QCustomPlot _cplot;
menu_NewGraph _menuNewGraph;
QList < t_Plot > _plots;
};

出了什么问题？

Answer 1

这些图是，您可以通过修改小部件的大小来检查，以便它们可见而无需这样做，您必须调用replot()。

void _addGraph(const QString & name, int bits_from, int bits_to)
{
t_Plot pl;
pl.p_layout = new QCPLayoutGrid;
pl.p_axisrect = new QCPAxisRect(&_cplot/*, false*/);
pl.p_layout->addElement(0, 0, pl.p_axisrect);
_cplot.plotLayout()->addElement(_plots.count(), 0, pl.p_layout);
_plots.append(pl);
_cplot.replot(); // <---
}