problems in a small dialog

[franky]

I wanted to create a small dialog that using buttons we can add some numbers.
First I designed a form by Qt Designer using Dialog Without Buttons template like this:

1.jpg

Then I wrote a calculator.h file like this:

#ifndef CALCULATOR_H
#define CALCULATOR_H
 
#include<QDialog>
#include "ui_Calculator.h"
 
class Calculator : public QDialog, public Ui::Calculator
{
    Q_OBJECT
 
public:
    Calculator(QWidget* parent = 0);
 
private slots:
   void myslot();
};
 
#endif // CALCULATOR_H

#ifndef CALCULATOR_H
#define CALCULATOR_H

#include<QDialog>
#include "ui_Calculator.h"

class Calculator : public QDialog, public Ui::Calculator
{
    Q_OBJECT

public:
    Calculator(QWidget* parent = 0);

private slots:
   void myslot();
};

#endif // CALCULATOR_H

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Then, a calculator.cpp this way:

#include <QtWidgets>
#include "calculator.h"
 
Calculator::Calculator(QWidget *parent)
    :QDialog(parent)
{
    setupUi(this);
 
    connect(oneButton,SIGNAL(clicked(bool)), lineEdit, SLOT(myslot()));
}
 
void Calculator::myslot(){
    lineEdit -> setText("1");
}

#include <QtWidgets>
#include "calculator.h"

Calculator::Calculator(QWidget *parent)
    :QDialog(parent)
{
    setupUi(this);

    connect(oneButton,SIGNAL(clicked(bool)), lineEdit, SLOT(myslot()));
}

void Calculator::myslot(){
    lineEdit -> setText("1");
}

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And finally the main.cpp this way:

#include <QApplication>
#include <QDialog>
 
#include "ui_Calculator.h"
 
int main(int argc, char* argv[])
{
    QApplication app(argc, argv);
 
    Ui::Calculator ui;
    QDialog* dialog = new QDialog;
    ui.setupUi(dialog);
    dialog -> show();
 
    return app.exec();
}

#include <QApplication>
#include <QDialog>

#include "ui_Calculator.h"

int main(int argc, char* argv[])
{
    QApplication app(argc, argv);

    Ui::Calculator ui;
    QDialog* dialog = new QDialog;
    ui.setupUi(dialog);
    dialog -> show();

    return app.exec();
}

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Now the code runs without any error but not as expected! That is when I click on '1' button nothing will be printed out onto the lineEdit.
Why please and how to solve it?

[anda_skoa]

You main() never creates an instance of Calculator, so there is no chance any of its could could ever be executed.

Instead of all the code between the QApplication creation and the return line, create an object of type Calculator and show it.

Cheers,
_

P.S.: additional suggestion would be to use the generated class as a member instead of inheriting from it

[franky]

Do you mean instead of:

int main(int argc, char* argv[])
{
    QApplication app(argc, argv);
    Ui::Calculator ui;
    QDialog* dialog = new QDialog;
    ui.setupUi(dialog);
    dialog -> show();
 
    return app.exec();
}

int main(int argc, char* argv[])
{
    QApplication app(argc, argv);
    Ui::Calculator ui;
    QDialog* dialog = new QDialog;
    ui.setupUi(dialog);
    dialog -> show();

    return app.exec();
}

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I should write:

int main(int argc, char* argv[])
{
    QApplication app(argc, argv);
 
    Calculator calc;
    calc.show();
 
    return app.exec();
}

int main(int argc, char* argv[])
{
    QApplication app(argc, argv);

    Calculator calc;
    calc.show();

    return app.exec();
}

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?

Can it be running?

[anda_skoa]

Yes, that is exactly what I meant and what you are intending to do.

Cheers.
_

[franky]

Thanks for the reply.
I made that changes but I got these errors:

1- C:\Users\Me\Documents\Qt\Calculator\main.cpp:9: error: 'Calculator' was not declared in this scope
Calculator calc;
^
2- C:\Users\Me\Documents\Qt\Calculator\main.cpp:10: error: 'calc' was not declared in this scope
calc.show();
^

[Ginsengelf]

Hi, you need to #include "calculator.h" in main.cpp

Ginsengelf

[franky]

Thank you.The problem is solved.