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# QMenuBar Class Reference
[com.trolltech.qt.gui module]

The `QMenuBar` class provides a horizontal menu bar. More...

Inherits `QWidget`.

## Detailed Description

The `QMenuBar` class provides a horizontal menu bar.

A menu bar consists of a list of pull-down menu items. You add menu items with `addMenu`. For example, asuming that `menubar` is a pointer to a `QMenuBar` and `fileMenu` is a pointer to a `QMenu`, the following statement inserts the menu into the menu bar:

        menubar->addMenu(fileMenu);

The ampersand in the menu item's text sets Alt+F as a shortcut for this menu. (You can use "&&" to get a real ampersand in the menu bar.)

There is no need to lay out a menu bar. It automatically sets its own geometry to the top of the parent widget and changes it appropriately whenever the parent is resized.

In most main window style applications you would use the menuBar() provided in `QMainWindow`, adding `QMenu`s to the menu bar and adding `QAction`s to the popup menus.

Example (from the Menus example):

            fileMenu = menuBar()->addMenu(tr("&File"));
            fileMenu->addAction(newAct);

Menu items may be removed with `removeAction`.

### Platform Dependent Look and Feel

Different platforms have different requirements for the appearance of menu bars and their behavior when the user interacts with them. For example, Windows systems are often configured so that the underlined character mnemonics that indicate keyboard shortcuts for items in the menu bar are only shown when the Alt key is pressed.

| The Plastique widget style, like most other styles, handles the Help menu in the same way as it handles any other menu.
| The Motif widget style treats Help menus in a special way, placing them at right-hand end of the menu bar.

### QMenuBar on Qt/Mac

`QMenuBar` on Qt/Mac is a wrapper for using the system-wide menu bar. If you have multiple menu bars in one dialog the outermost menu bar (normally inside a widget with widget flag Qt::Window) will be used for the system-wide menu bar.

Qt/Mac also provides a menu bar merging feature to make `QMenuBar` conform more closely to accepted Mac OS X menu bar layout. The merging functionality is based on string matching the title of a `QMenu` entry. These strings are translated (using QObject::tr()) in the "`QMenuBar`" context. If an entry is moved its slots will still fire as if it was in the original place. The table below outlines the strings looked for and where the entry is placed if matched:

String matches | Placement | Notes
--- | --- | ---
about.* | Application Menu | About <application name> | If this entry is not found no About item will appear in the Application Menu
config, options, setup, settings or preferences | Application Menu | Preferences | If this entry is not found the Settings item will be disabled
quit or exit | Application Menu | Quit <application name> | If this entry is not found a default Quit item will be created to call QApplication::quit()

You can override this behavior by using the QAction::menuRole() property.

If you wish to make all windows in a Mac application share the same menu bar, you need to create a menu bar that does not have a parent. The menu bar is created like this:

          QMenuBar *menuBar = new QMenuBar(0);

Note: The text used for the application name in the menu bar is obtained from the value set in the `Info.plist` file in the application's bundle. See Deploying an Application on Qt/Mac for more information.

### Examples

The Menus example shows how to use `QMenuBar` and `QMenu`. The other main window application examples also provide menus using these classes.

See also `QMenu`, `QShortcut`, `QAction`, Introduction to Apple Human Interface Guidelines, GUI Design Handbook: Menu Bar, and Menus Example.