connect a QPushButton matrix with a function

[harmodrew]

Hello, here I am again!

I'm trying to connect the clicked() events of the buttons of a QPushButton matrix with a custom function. The problem is that the function needs the indexes of the clicked button...in the connect() reference is told that I cannot do such a thing:

QPushButton **p;
p = new QPushButton*[nrow];
for (int i=0; i<nrow; i++)
        p[i] = new QPushButton[ncol];
 
for (int i=0; i<nrow; i++)
    for (int j=0; j<ncol; j++)
         p[i][j].connect(&p[i][j],SIGNAL(clicked()), actObj, SLOT(triggerFunc(int i, int j)));

QPushButton **p;
p = new QPushButton*[nrow];
for (int i=0; i<nrow; i++)
        p[i] = new QPushButton[ncol];

for (int i=0; i<nrow; i++)
    for (int j=0; j<ncol; j++)
         p[i][j].connect(&p[i][j],SIGNAL(clicked()), actObj, SLOT(triggerFunc(int i, int j)));

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actObj is an object which holds the slot triggerFunc(int, int).
I need to index the button of p that was clicked and call the triggerFunc() function using i and j properly...are there other ways to connect a widget, object, button, etc, with a function?

thanks again

[Zlatomir]

Look like signal mapper is what you need

[harmodrew]

yeah, I thiks it will help! I'll try it tomorrow...good night and thanks a lot!

[aamer4yu]

Also do remember the number of arguments of SLOT must be equal to or less than the arguments of the SIGNAL

[harmodrew]

but how do I assign an argument of the SLOT to an argument of the SIGNAL? The order must be the same?

[harmodrew]

I'm having troubles with the code here:

inputmatrix.h:

#ifndef INPUTMATRIX_H
#define INPUTMATRIX_H
#include <QPushButton>
#include <QObject>
#include <QSignalMapper>
 
class InputMatrix : QObject
{
    Q_OBJECT
private:
    QPushButton ** p;
    int nrow;
    int ncol;
     QSignalMapper *signalMapper;
public:
    InputMatrix();
    InputMatrix(int nrow, int ncol);
    ~InputMatrix();
    void Show(QWidget*);
    QPushButton GetItem(int i,int j);
public slots:
    void SetItem(const QString &ID);
};
 
#endif // INPUTMATRIX_H

#ifndef INPUTMATRIX_H
#define INPUTMATRIX_H
#include <QPushButton>
#include <QObject>
#include <QSignalMapper>

class InputMatrix : QObject
{
    Q_OBJECT
private:
    QPushButton ** p;
    int nrow;
    int ncol;
     QSignalMapper *signalMapper;
public:
    InputMatrix();
    InputMatrix(int nrow, int ncol);
    ~InputMatrix();
    void Show(QWidget*);
    QPushButton GetItem(int i,int j);
public slots:
    void SetItem(const QString &ID);
};

#endif // INPUTMATRIX_H

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inputmatrix.cpp:

#include "inputmatrix.h"
#include <QPushButton>
#include "mainwindow.h"
#include <QSignalMapper>
#include <QString>
#include <QMessageBox>
#include <QChar>
 
InputMatrix::InputMatrix()
{}
 
InputMatrix::InputMatrix(int nr, int nc)
{
    ncol=nc;
    nrow = nr;
    p = new QPushButton*[nrow];
    for (int i=0; i<nrow; i++)
        p[i] = new QPushButton[ncol];
 
}
 
void InputMatrix::Show(QWidget *obj)
{
    int alt = (obj->height()-100)/nrow;
 
    signalMapper= new QSignalMapper(this);
 
    const QString ID = "ij";  // this will identify the buttons in the PushButton matrix
    for (int i=0; i<nrow; i++)
    {
        ID.insert(0,(Qchar) i);       // FIRST ERROR
        for (int j=0; j<ncol; j++)
        {
            ID.insert(1,(QChar) j);     // SECOND ERROR
            p[i][j].setParent(obj); // obj = window on which I'll show the matrix
            p[i][j].setGeometry(50+(j*alt), 70 +(i*alt),alt, alt);
            connect(&p[i][j], SIGNAL(clicked()), signalMapper, SLOT(map()));
            signalMapper->setMapping(&p[i][j], ID);
            p[i][j].show();
        }
    }
    connect(signalMapper, SIGNAL(mapped(const QString &)),
                 this, SLOT(SetItem(const QString &)));
 
}
 
void InputMatrix::SetItem(const QString & ID)
{
 
    QMessageBox msg;
    QString aux = "You have pressed ";
    aux.append(ID);
    msg.setText(aux);
    msg.exec();
 
}
 
QPushButton InputMatrix::GetItem(int i,int j)
{
    //return p[i][j];
 
}
 
InputMatrix::~InputMatrix()
{
    for (int i=0; i<nrow; i++)
        delete [] p[i];
    delete p;
 
}

#include "inputmatrix.h"
#include <QPushButton>
#include "mainwindow.h"
#include <QSignalMapper>
#include <QString>
#include <QMessageBox>
#include <QChar>

InputMatrix::InputMatrix()
{}

InputMatrix::InputMatrix(int nr, int nc)
{
    ncol=nc;
    nrow = nr;
    p = new QPushButton*[nrow];
    for (int i=0; i<nrow; i++)
        p[i] = new QPushButton[ncol];

}

void InputMatrix::Show(QWidget *obj)
{
    int alt = (obj->height()-100)/nrow;

    signalMapper= new QSignalMapper(this);

    const QString ID = "ij";  // this will identify the buttons in the PushButton matrix
    for (int i=0; i<nrow; i++)
    {
        ID.insert(0,(Qchar) i);       // FIRST ERROR
        for (int j=0; j<ncol; j++)
        {
            ID.insert(1,(QChar) j);     // SECOND ERROR
            p[i][j].setParent(obj); // obj = window on which I'll show the matrix
            p[i][j].setGeometry(50+(j*alt), 70 +(i*alt),alt, alt);
            connect(&p[i][j], SIGNAL(clicked()), signalMapper, SLOT(map()));
            signalMapper->setMapping(&p[i][j], ID);
            p[i][j].show();
        }
    }
    connect(signalMapper, SIGNAL(mapped(const QString &)),
                 this, SLOT(SetItem(const QString &)));

}

void InputMatrix::SetItem(const QString & ID)
{
    
    QMessageBox msg;
    QString aux = "You have pressed ";
    aux.append(ID);
    msg.setText(aux);
    msg.exec();

}

QPushButton InputMatrix::GetItem(int i,int j)
{
    //return p[i][j];

}

InputMatrix::~InputMatrix()
{
    for (int i=0; i<nrow; i++)
        delete [] p[i];
    delete p;

}

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the error is the same at both of the rows I commented in the code. It is:

passing 'const QString' as 'this' argument of 'QString& QString::insert(int, QChar)' discards qualifier

why I'm wrong?

[harmodrew]

solved simply I declared a const ID QString so the compiler was warning me that I was changing a const string

but now I have a "undefined reference to 'vtable for InputMatrix' " error on the constructor and destructor prototype lines of code...

SOLVED: I only had to run "qmake"