Parent and Child Window Communication in Qt - Child Window opens twice - qt

Question

I have two windows, one parent and one child. In parent window, I have a Next button, which onClick()'ed, opens up child window, but in my case two child windows are opening, what is the mistake am doing!?
Here are my codes:
.h files
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <info.h>
#include <QtGui>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow {
Q_OBJECT
public:
MainWindow(QWidget *parent = 0);
~MainWindow();
protected:
void changeEvent(QEvent *e);
private:
Ui::MainWindow *ui;
void setSignals();
private slots:
void process();
};
#endif // MAINWINDOW_H
info.h
#ifndef INFO_H
#define INFO_H
#include <QMainWindow>
namespace Ui {
class info;
}
class info : public QMainWindow {
Q_OBJECT
public:
info(QWidget *parent = 0);
~info();
protected:
void changeEvent(QEvent *e);
private:
Ui::info *ui;
};
#endif // INFO_H
.cpp files
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtGui/QApplication>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
setSignals();
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::changeEvent(QEvent *e)
{
QMainWindow::changeEvent(e);
switch (e->type()) {
case QEvent::LanguageChange:
ui->retranslateUi(this);
break;
default:
break;
}
}
void MainWindow::setSignals(){
connect(ui->pushButton,SIGNAL(clicked()),this,SLOT(process()));
connect(ui->pushButton_2,SIGNAL(clicked()),this,SLOT(close()));
}
void MainWindow::process(){
info *i;
i = new info;
this -> hide();
i -> show();
}
info.cpp
#include "info.h"
#include "ui_info.h"
info::info(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::info)
{
ui->setupUi(this);
}
info::~info()
{
delete ui;
}
void info::changeEvent(QEvent *e)
{
QMainWindow::changeEvent(e);
switch (e->type()) {
case QEvent::LanguageChange:
ui->retranslateUi(this);
break;
default:
break;
}
}
main.cpp
#include <QtGui/QApplication>
#include "mainwindow.h"
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}

Answer 1

I solved it, here was the problem:
In designer header file i.e., in ui_mainwindow.h, I have:
QObject::connect(pushButton, SIGNAL(clicked()), MainWindow, SLOT(process()));
QObject::connect(pushButton_2, SIGNAL(clicked()), MainWindow, SLOT(close()));
and in the source file i.e., mainwindow.cpp in setSignals(), I have again stated:
void MainWindow::setSignals()
{
connect(ui->pushButton,SIGNAL(clicked()),this,SLOT(process()));
connect(ui->pushButton_2,SIGNAL(clicked()),this,SLOT(close()));
}
So with the two connects, we get two calls to process() , we have to comment anyone to show only one child window. That's it :-)