A Qt könyvtárban írt programomra a Qt creator azt írja, hogy no such slot mit csináljak, hogy jó legyen?

Lefordul egyébként el is indul de hiába nyomkodom a létrehozott gombot semmi mert a SLOT ban a függvény amit létrehoztam a header fájlban azt nem találja a slot.

buttons.cpp

#include "buttons.h"

Buttons::Buttons(QWidget *parent):

Windows(parent),

quitButton(new QPushButton("Quit" ,this)),

plus(new QPushButton("+", this)),

minus(new QPushButton("-", this)),

label(new QLabel("0", this))

{

quitButton->setGeometry(0, 0, 35, 25);

plus->setGeometry(0, 50, 50, 30);

minus->setGeometry(0, 80, 50, 30);

label->setGeometry(100, 65, 20, 30);

connect(quitButton, SIGNAL(clicked()), qApp, SLOT(quit()));

connect(plus, SIGNAL(clicked()), this, SLOT(onPlus()));

connect(minus, SIGNAL(clicked()), this, SLOT(onMinus()));

}

Buttons::~Buttons()

{

delete quitButton;

delete plus;

delete minus;

delete label;

}

void Buttons::onPlus()const

{

int number(label->text().toInt());

label->setText(QString::number(++number));

}

void Buttons::onMinus()const

{

int number(label->text().toInt());

label->setText(QString::number(--number));

}

buttons.h

#ifndef BUTTONS_H

#define BUTTONS_H

#include <QApplication>

#include <QPushButton>

#include <QLabel>

#include "windows.h"

class Buttons: public Windows

{

public:

Buttons(QWidget *parent = nullptr);

~Buttons();

private slots:

void onPlus()const;

void onMinus()const;

private:

QPushButton *const quitButton;

QPushButton *const plus;

QPushButton *const minus;

QLabel *const label;

};

#endif // BUTTONS_H

windows.cpp

#include <windows.h>

Windows::Windows(QWidget *parent):

QMainWindow(parent)

{

this->setFixedSize(550, 550);

this->setWindowTitle("Gamedesire Pool8 Fraud");

this->setWindowFlags(Qt::WindowMinimizeButtonHint | Qt::WindowCloseButtonHint);

}

Windows::~Windows()

{

}

windows.h

#ifndef MAINWINDOW_H

#define MAINWINDOW_H

#include <QMainWindow>

class Windows: public QMainWindow

{

public:

Windows(QWidget *parent = nullptr);

~Windows();

};

#endif // MAINWINDOW_H

main.cpp

#include "buttons.h"

typedef Buttons MyFinalWindow;

int main(int argc, char *argv[])

{

QApplication App(argc, argv);

MyFinalWindow MyWindow;

MyWindow.show();

return App.exec();

}