QT Slots and signals, showing 2nd form/window - c++

Question

I have a QT application and I'm trying to have a button in one of my windows open another window.
The way I have done my window objects so far in the main is like this:
Website control;
control.show();
This displays my first window fine and if I declare my other window in a similar way that also displays at runtime, although this is not what I want
Then in a separate header file:
class Website: public QWidget, public Ui::Website
{
public:
Website();
}
Then in the corresponding Cpp file I have:
Website::Website()
{
setupUi(this);
}
Now all this works and have added a custom slot so that when I click a button it triggers a slot in my other cpp file. The issue is I'm not sure how to show my other window as I declare them in my main so can't access them to do .show()?
Any help would be appreciated, I'm fairly new to C++ and QT

Answer 1

It's not clear to me what you want to do. But i might understand your struggle as I had one myself the first time approaching this framework.
So let's say you have a MainWindow class that controls the main Window view. Than you want to create a second window controlled by Website class.
You then want to connect the two classes so that when you click a button on the Website window something happens in the MainWindow.
I made a simple example for you that is also on GitHub:
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "website.h"
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
public slots:
void changeText();
private slots:
void on_openButton_clicked();
private:
Ui::MainWindow *ui;
//You want to keep a pointer to a new Website window
Website* webWindow;
};
#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);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::changeText()
{
ui->text->setText("New Text");
delete webWindow;
}
void MainWindow::on_openButton_clicked()
{
webWindow = new Website();
QObject::connect(webWindow, SIGNAL(buttonPressed()), this, SLOT(changeText()));
webWindow->show();
}
website.h
#ifndef WEBSITE_H
#define WEBSITE_H
#include <QDialog>
namespace Ui {
class Website;
}
class Website : public QDialog
{
Q_OBJECT
public:
explicit Website(QWidget *parent = 0);
~Website();
signals:
void buttonPressed();
private slots:
void on_changeButton_clicked();
private:
Ui::Website *ui;
};
#endif // WEBSITE_H
website.cpp
#include "website.h"
#include "ui_website.h"
Website::Website(QWidget *parent) :
QDialog(parent),
ui(new Ui::Website)
{
ui->setupUi(this);
}
Website::~Website()
{
delete ui;
}
void Website::on_changeButton_clicked()
{
emit buttonPressed();
}
Project composed:
SOURCES += main.cpp\
mainwindow.cpp \
website.cpp
HEADERS += mainwindow.h \
website.h
FORMS += mainwindow.ui \
website.ui
Consider the Uis to be composed:
Main Window: a label called "text" and a button called "openButton"
Website Window: a button called "changeButton"
So the keypoints are the connections between signals and slots and the management of windows pointers or references.