I am developing a code snippet to perform similar, not identical actions when I click on the sub menu item list. Please check the attached snapshot. QSignalMapper is the best solution to connect multiple signals to the same slot.
snap1.jpg

But I am not able to exactly place, which signal is to be called for which slot. I have read a lot of theory about QSignalMapper,
Qt Code: 
  1. http://qt-project.org/doc/qt-4.8/qsignalmapper.html
  2. http://doc.qt.digia.com/qq/qq10-signalmapper.html#thesignalmapperapproach
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even implemented their codes. Unlike the mentioned sample programs, my QAction objects apparently cannot be defined like we define elements inside an array, coz their names were auto-generated by the design window.
snap2.jpg

I am not able to understand, what should I place as SIGNAL here, and when should I use the setMapping function? If I use setMapping function, which parameters should I implement? I am simply not getting the concept thorough, not knowing what to do, whom to ask and making the mistake in my code here. Can you please advise me what I am doing wrong? I checked this for reference coz he had similar issue:
Qt Code: 
  1. http://stackoverflow.com/questions/14151443/how-to-pass-a-qstring-to-a-qt-slot-from-a-qmenu-via-qsignalmapper-or-otherwise/14157471#14157471
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Here's the code which requires 4-5 steps, which I am not getting, to be added for making it work:

mainwindow.h
Qt Code: 
  1. #ifndef MAINWINDOW_H
  2. #define MAINWINDOW_H
  3.  
  4. #include <QMainWindow>
  5. #include <QDebug>
  6. #include <QSignalMapper>
  7.  
  8. namespace Ui {
  9. class MainWindow;
  10. }
  11.  
  12. class MainWindow : public QMainWindow
  13. {
  14.     Q_OBJECT
  15.  
  16. public:
  17.     explicit MainWindow(QWidget *parent = 0);
  18.     ~MainWindow();
  19.  
  20.  
  21. private:
  22.     Ui::MainWindow *ui;
  23.     void createActions();
  24.  
  25. private slots:
  26.     void interval();
  27.     void help();
  28.     int setAreaThreshold();
  29.  
  30. };
  31.  
  32. #endif // MAINWINDOW_H
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mainwindow.cpp
Qt Code: 
  1. #include "mainwindow.h"
  2. #include "ui_mainwindow.h"
  3. //#include "intervaldialog.h"
  4. //#include "help.h"
  5.  
  6. int i =25;
  7. MainWindow::MainWindow(QWidget *parent) :
  8.     QMainWindow(parent),
  9.     ui(new Ui::MainWindow)
  10. {
  11.     ui->setupUi(this);
  12.     createActions();
  13. }
  14.  
  15. MainWindow::~MainWindow()
  16. {
  17.     delete ui;
  18. }
  19.  
  20. void MainWindow::createActions()
  21. {
  22.     ui->actionInterval->setStatusTip(tr("Set the interval for capturing delta & reference images"));
  23.     connect(ui->actionInterval, SIGNAL(triggered()), this, SLOT(interval()));
  24.  
  25.    QSignalMapper *pSignalMapper = new QSignalMapper(this);
  26.    connect(ui->menuArea_Threshold, SIGNAL(triggered(QAction*)), this, SLOT(setAreaThreshold()));
  27.  
  28.  
  29.     ui->menuHelp->setStatusTip(tr("help "));
  30. }
  31.  
  32. void MainWindow::interval()
  33. {
  34.     qDebug()<<"inside interval qdialog";
  35. }
  36.  
  37. int MainWindow::setAreaThreshold()
  38. {
  39.     qDebug()<<"setting area threshold";
  40.  
  41. //    qDebug()<<str;
  42. //    int i = str.toInt();
  43. //    qDebug()<<i;
  44. //    QString areaThresholdString;
  45. //    areaThresholdString = ui->action25_sec->text();
  46. //    switch (areaThresholdString) {
  47. //    case 25:
  48. //        qDebug()<<"25";
  49. //        break;
  50. //    default:
  51. //        qDebug()<<"default";
  52. //        break;
  53. //    }
  54.  
  55.     return 0;
  56. }
  57.  
  58. void MainWindow::help()
  59. {
  60.     Help help;
  61.     help.exec();
  62. }
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main.cpp
Qt Code: 
  1. #include "mainwindow.h"
  2. #include <QApplication>
  3.  
  4. int main(int argc, char *argv[])
  5. {
  6.     QApplication a(argc, argv);
  7.     MainWindow w;
  8.     w.show();
  9.  
  10.     return a.exec();
  11. }
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