How to use qAction submenu in Qt

Question

I want to implement simple commands like a qDebug() when I click on a sub menu in the mainwindow. I was referring to sample program given along with the Qt 5 IDE (...\Qt\Qt5.2.0\5.2.0\msvc2010\examples\widgets\mainwindows\menus), and using it, I managed to construct the code. I do not receive any compile time or run time errors.

I created the mainwindow.ui using the design mode. It has an object of the QAction class called actionInterval.

But when I click on it, nothing happens, I am not able to implement the command in void interval(). I guess I am not connecting properly. What am I missing here? Please advise.

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QDebug>
namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();


private:
    Ui::MainWindow *ui;
    void createActions();

private slots:
    void interval();
};

#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    createActions();
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::createActions()
{
    ui->actionInterval = new QAction(tr("&Interval"), this);
    ui->actionInterval->setStatusTip(tr("Set the interval for capturing delta & reference images"));
    connect(ui->actionInterval, SIGNAL(triggered()), this, SLOT(interval()));
}

void MainWindow::interval()
{
    qDebug()<<"inside interval qdialog";
}

main.cpp

#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    return a.exec();
}

Answer 1

void MainWindow::createActions()
{
    ui->actionInterval->setStatusTip(tr("Set the interval for capturing delta & reference images"));
    connect(ui->actionInterval, SIGNAL(triggered()), this, SLOT(interval()));
}

You shouldn't need that ui->actionInterval = new QAction(tr("&Interval"), this); line, the ui->setupUi() handles that for you, so it's potentially causing an incorrect reference so when you do click on it it's not firing correctly.