CODEWITHSUNDEEP
c++qt
Lizard_Paszczyk
Lizard_Paszczyk

Reputation: 159

Qt: How to transfer base class to object created in that class

I've created base class - MainWindow. In this class I create object of another class "SecondWindow". By using object of SecondWindow I want to use function() method that is defined in base class. How can I do this?

I've tried to transfer my base class as a parameter to SecondWindow object but that wasn't working (probably becouse in MainWindow I have included "secondWindow.h" and in SecondWindow I tried to include "mainwindow.h" header files). Is there way to simply use functions/variables of base class?

mainwindow.h

#include<QMainWindow>
#include "secondwindow.h"
class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow();
    SecondWindow *secondWindow;
    void function();
}

mainwindow.cpp

#include "mainwindow.h"
MainWindow::MainWindow()
{
    secondWindow = new secondWindow();
    function();
}
void MainWindow::function()
{
    qDebug()<<"yes";
}

secondwindow.h

class SecondWindow : public QMainWindow
{
    Q_OBJECT
public:
    SecondWindow();

}

secondwindow.cpp

#include "secondwindow.h"

SecondWindow::SecondWindow()
{
//here I want to use function();
}

Upvotes: 0

Views: 111

Answers (1)

Chris
Chris

Reputation: 2304

You would want to inherit your MainWindow class, which would then inherit QMainWindow()

So in secondwindow.h you would change

class SecondWindow : public QMainWindow
{
    Q_OBJECT
public:
    SecondWindow();

};

to

#include "mainwindow.h"    
class SecondWindow : public MainWindow
{
    Q_OBJECT
public:
    SecondWindow();

};

And you will then be able to use function() in secondwindow.cpp

Also, you have another issue at hand and it's that your mainwindow uses a pointer to second window, but you will then have a circular dependence issue. (You need SecondWindow in order to compile MainWindow, however, you want SecondWindow to be able to use function()).

To resolve this, you need to forward-declare SecondWindow in your MainWindow class.

In mainwindow.h remove #include "secondwindow.h" and replace it with class SecondWindow;

Upvotes: 2

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