The line edit widget shows nothing - qt

Question

I've recently started learning Qt and I'm a beginner of it now. So as first example for myself I wrote the following simple example.
The example is named Calculator. It now only has two buttons an a line edit. It's here:
:
My Calculator.h is 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
And the Calculator.cpp is this:
#include <QtWidgets>
#include "calculator.h"
Calculator::Calculator(QWidget *parent)
:QDialog(parent)
{
setupUi(this);
connect(oneButton,SIGNAL(clicked(bool)), this, SLOT(myslot()));
}
void Calculator::myslot(){
lineEdit -> setText("1");
}
And this is the main.cpp:
#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();
}
The program runs fine without any error. But when I click on 1 button, nothing will be printed/shown in the line edit. Why please?
And what part of my program should I change to solve the issue please?

Answer 1

You are setting up the wrong class in your main.
You should use your custom Calculator class and not QDialog.
setupUi only initializes your elements but your code in Calculator never gets called. Your main should look like this:
int main(int argc, char* argv[])
{
QApplication app(argc, argv);
Calculator calc; //using your Calculator class.
calc.show();
return app.exec();
}
And don't include ui_calculator.h but calculator.h