QMenuBar not displaying

Saviz

I am trying to create a simple QMenuBar with one QMenu.

mainwindow.h file:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QMenuBar>
#include <QMenu>

class MainWindow : public QMainWindow
{
// Macros
    Q_OBJECT

// Constructors
public:
    MainWindow(QWidget *parent = nullptr);

// Destructors
public:
    ~MainWindow();

// QWidgets
private:
    QWidget *QWidget_CenteralWidget;
    QMenuBar *QMenuBar_Bar;
    QMenu *QMenu_File;

// Methods
private:
    void setupGUI();
};

#endif

mainwindow.cpp file:

#include "mainwindow.h"

MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent)
{
    setupGUI();
}

MainWindow::~MainWindow()
{
}

mainwindow_gui.cpp file:

#include "mainwindow.h"

void MainWindow::setupGUI()
{
    // MainWindow
    if (this->objectName().isEmpty())
    {
        this->setObjectName(QString::fromUtf8("QMainWindow_MainWindow"));
    }

    this->setWindowState(Qt::WindowMaximized);


    // Centeral Widget
    QWidget_CenteralWidget = new QWidget(this);

    QWidget_CenteralWidget->setStyleSheet("background-color: gray;");

    this->setCentralWidget(QWidget_CenteralWidget);


    // QMenuBar
    QMenuBar_Bar = new QMenuBar(this);
    QMenuBar_Bar->setVisible(true);
    QMenuBar_Bar->setStyleSheet("background-color: red;");

    QMenu_File = new QMenu(QMenuBar_Bar);
    QMenu_File->setObjectName(

                QString::fromUtf8("QMenu_File")
                );


    QMenuBar_Bar->addMenu(QMenu_File);

    this->setMenuBar(QMenuBar_Bar);
}

Here is the output:

As you can see, the menu bar is nowhere to be found.

Why is this happening?

Chris Kawa

Your menu has no text, so it occupies no space. Give it something to show e.g.

QMenu_File = new QMenu("&File", QMenuBar_Bar);
QMenuBar_Bar->addMenu(QMenu_File);

or a shorthand:

QMenu_File = QMenuBar_Bar->addMenu("&File");

Btw. setObjectName has an overload that takes QAnyStringView, so you can use it and save on dynamically allocating temporary QString: setObjectName("QMainWindow_MainWindow").

Btw.2 Calling this->setWindowState(Qt::WindowMaximized);or any other variant of show() in the constructor is a bad practice. A widget should not dictate how it is shown. This should be the responsibility of the code that creates it. It would also make calling QMenuBar_Bar->setVisible(true); unnecessary, as it would be shown automatically when the parent is shown.

Saviz

@Chris-Kawa Thank you for your solutions and suggestions. I made sure to use the overload and to change my code to use the following in the appropriate place:

this->setWindowState(Qt::WindowMaximized);

Thank you again.