Issues with signal and slot- Qt4

adiQt4

I have created a GUI which involves selection of topics from one ComboBox (evaluation_box) leading to load all the topics related to that particular topic into another ComboBox (sequence_combo_box).

The code used for SIGNAL/SLOT is as follows:

@ connect(ui_.evaluation_box, SIGNAL(currentIndexChanged(QString)), ui_.sequence_combo_box, SLOT(readSequenceFile(char *,char *,struct dirent *)));
@

The header file includes the following:

@#ifndef rqt_get_sequence_feeder__GetSequenceFeeder_H
#define rqt_get_sequence_feeder__GetSequenceFeeder_H

#include <rqt_gui_cpp/plugin.h>

#include <ui_get_sequence_feeder.h>
#include <dirent.h>
#include <image_transport/image_transport.h>
#include <sensor_msgs/Image.h>
#include <opencv2/core/core.hpp>
#include <QImage>
#include <QList>
#include <QMutex>
#include <QString>
#include <QSize>
#include <QWidget>
#include <vector>

namespace rqt_get_sequence_feeder {

class GetSequenceFeeder
  : public rqt_gui_cpp::Plugin
 {

  Q_OBJECT
    public:
       GetSequenceFeeder();

    protected slots:            
      virtual void onFrameChanged(int);
      virtual void readSequenceFile&#40;char *folder,char *sequence,struct dirent *select&#41;;
                                      .
                                      .
                                      .
   protected:    
     Ui::GetSequenceFeederWidget ui_;

 };
}@

And the .cpp is as follows:

@using namespace std;
namespace rqt_get_sequence_feeder {

GetSequenceFeeder::GetSequenceFeeder()
: rqt_gui_cpp::Plugin()
, widget_(0)
{
setObjectName("GetSequenceFeeder");
}

void GetSequenceFeeder::initPlugin(qt_gui_cpp::PluginContext& context)
{
connect(ui_.evaluation_box, SIGNAL(currentIndexChanged(QString)),ui_.sequence_combo_box, SLOT(readSequenceFile(char *,char *,struct dirent *)));
.
.
.
}

void GetSequenceFeeder::readSequenceFile(char *folder ,char *sequenceFile,struct dirent *select)
{
.
.
.
}@

But, on doing so I get the following error message:

@Object::connect: No such slot QComboBox::readSequenceFile(char *,char *,struct dirent *)
Object::connect: (sender name: 'evaluation_box')
Object::connect: (receiver name: 'sequence_combo_box')@

I have the function readSequenceFile(char *folder,char *sequence,struct dirent *select); declared in the header file as protected slots: I also tried declaring it as public slot:, did not work. I don't understand what am I doing wrong.

goblincoding

There are a number of issues here, but to address your "No such slot" problem, it seems to me as if you are attempting to connect your SIGNAL to a QComboBox (ui_.sequence_combo_box)...and QComboBox does not have a SLOT called readSequenceFile(...)

To connect to your sequence feeder object's readSequenceFile(...) slot, you should probably connect to "this".

@connect(ui_.evaluation_box, SIGNAL(currentIndexChanged(QString)), this, SLOT(readSequenceFile(char *,char *,struct dirent *))); @

Having said that, you will now run into additional issues since your signatures don't match. I suggest you read the docs a little bit more :)