Signals&Slots Error: No matching function for call to 'connect' (requires 3 arguments, but 4 were provided)

TUStudi

Hello,

I am trying the following:

I have a .ui form and I want to make a Plot with QCustomPlot in one widget on this form. But I do not want to write the code that is necassary in the mainwindow.cpp but creating a new class, setting up the diagramm there and call this method from my mainwindow.cpp file, like this:

/*PlotterModel.cpp*/


#include "PlotterModel.h"
#include "ui_PlotterView.h"

PlotterModel::PlotterModel()
{ 
}


void PlotterModel::setUpPlot(QCustomPlot *customPlotWidget)
{
    customPlotWidget->addGraph(); // blue line
    customPlotWidget->graph(0)->setPen(QPen(QColor(40, 110, 255)));
    customPlotWidget->addGraph(); // red line
    customPlotWidget->graph(1)->setPen(QPen(QColor(255, 110, 40)));

    QSharedPointer<QCPAxisTickerTime> timeTicker(new QCPAxisTickerTime);
    timeTicker->setTimeFormat("%h:%m:%s");
    customPlot->xAxis->setTicker(timeTicker);
    customPlot->axisRect()->setupFullAxesBox();
    customPlot->yAxis->setRange(-1.2, 1.2);

    // make left and bottom axes transfer their ranges to right and top axes:
    connect(customPlotWidget->xAxis, SIGNAL(rangeChanged(QCPRange)), customPlotWidget->xAxis2, SLOT(setRange(QCPRange)));
    connect(customPlotWidget->yAxis, SIGNAL(rangeChanged(QCPRange)), customPlotWidget->yAxis2, SLOT(setRange(QCPRange)));

    // setup a timer that repeatedly calls MainWindow::realtimeDataSlot:
    connect(dataTimer, SIGNAL(timeout()), this, SLOT(realtimeDataSlot()));
    dataTimer->start(0); // Interval 0 means to refresh as fast as possible
}

here is my header file for this class

/*PlotterModel.h*/

#ifndef PLOTTERMODEL_H
#define PLOTTERMODEL_H
#include <qcustomplot.h>
#include <QTimer>

class PlotterModel
{
    Q_OBJECT

public:
    PlotterModel();
    void setUpAccelerationDiagram(QCustomPlot *customPlotWidget);

      QTimer *dataTimer = new QTimer();
};

#endif // PLOTTERMODEL_H

So, now I want to call the above defined method setupPlot() and the parameter is my widget in my .ui file which I promotet to QCustomPlot as in the basic tutorial. So how can I call this method from my mainwindow.cpp file, can I call ui->customPlotWidget->replot() from my mainwindow.cpp? Because all my connect statements from my method setupPlot() give me the error:

PlotterModel.cpp:29:5: error: no matching function for call to 'connect'
winsock.h:751:16: note: candidate function not viable: requires 3 arguments, but 4 were provided

Christian Ehrlicher

Since PlotterModel is not derived from QObject there is also no function QObject::connect() which could be called. So it's using another connect function from winsock.h which does not match.
--> you forgot to derive from QObject (although you already added Q_OBJECT which should trigger a warning).

Pl45m4

@TUStudi said in Signals&Slots Error: No matching function for call to 'connect' (requires 3 arguments, but 4 were provided):

So how can I call this method from my mainwindow.cpp file

In MainWindow.cpp

PlotterModel *pM = new PlotterModel();

pM->setupPlot( ui->yourCustomPlotWidget );

or use a connection to setup your PlotterModel on mainWindow initialization.

TUStudi

Thank you both, it works now.