Class MenuBar

java.lang.Object

java.awt.MenuComponent

java.awt.MenuBar

All Implemented Interfaces:

MenuContainer, Serializable, Accessible

public class MenuBar
extends MenuComponent
implements MenuContainer, Accessible

The MenuBar class encapsulates the platform's concept of a menu bar bound to a frame. In order to associate the menu bar with a Frame object, call the frame's setMenuBar method.

This is what a menu bar might look like:

A menu bar handles keyboard shortcuts for menu items, passing them along to its child menus. (Keyboard shortcuts, which are optional, provide the user with an alternative to the mouse for invoking a menu item and the action that is associated with it.) Each menu item can maintain an instance of MenuShortcut. The MenuBar class defines several methods, shortcuts() and getShortcutMenuItem(MenuShortcut) that retrieve information about the shortcuts a given menu bar is managing.

Since:

1.0

See Also:

• Frame
• Frame.setMenuBar(java.awt.MenuBar)
• Menu
• MenuItem
• MenuShortcut
• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	MenuBar.AccessibleAWTMenuBar	Inner class of MenuBar used to provide default support for accessibility.

Nested classes/interfaces declared in class MenuComponent

MenuComponent.AccessibleAWTMenuComponent

Modifier and Type	Class	Description
protected class	MenuComponent.AccessibleAWTMenuComponent	Inner class of MenuComponent used to provide default support for accessibility.

Constructor Summary

Constructors

Constructor	Description
MenuBar()	Creates a new menu bar.

Method Summary

Modifier and Type	Method	Description
Menu	add(Menu m)	Adds the specified menu to the menu bar.
void	addNotify()	Creates the menu bar's peer.
int	countMenus()	Deprecated. As of JDK version 1.1, replaced by getMenuCount().
void	deleteShortcut(MenuShortcut s)	Deletes the specified menu shortcut.
AccessibleContext	getAccessibleContext()	Gets the AccessibleContext associated with this MenuBar.
Menu	getHelpMenu()	Gets the help menu on the menu bar.
Menu	getMenu(int i)	Gets the specified menu.
int	getMenuCount()	Gets the number of menus on the menu bar.
MenuItem	getShortcutMenuItem(MenuShortcut s)	Gets the instance of MenuItem associated with the specified MenuShortcut object, or null if none of the menu items being managed by this menu bar is associated with the specified menu shortcut.
void	remove(int index)	Removes the menu located at the specified index from this menu bar.
void	remove(MenuComponent m)	Removes the specified menu component from this menu bar.
void	removeNotify()	Removes the menu bar's peer.
void	setHelpMenu(Menu m)	Sets the specified menu to be this menu bar's help menu.
Enumeration<MenuShortcut>	shortcuts()	Gets an enumeration of all menu shortcuts this menu bar is managing.

Methods declared in class MenuComponent

dispatchEvent, getFont, getName, getParent, getTreeLock, paramString, postEvent, processEvent, setFont, setName, toString

Modifier and Type	Method	Description
final void	dispatchEvent(AWTEvent e)	Delivers an event to this component or one of its sub components.
Font	getFont()	Gets the font used for this menu component.
String	getName()	Gets the name of the menu component.
MenuContainer	getParent()	Returns the parent container for this menu component.
protected final Object	getTreeLock()	Gets this component's locking object (the object that owns the thread synchronization monitor) for AWT component-tree and layout operations.
protected String	paramString()	Returns a string representing the state of this MenuComponent.
boolean	postEvent(Event evt)	Deprecated. As of JDK version 1.1, replaced by dispatchEvent.
protected void	processEvent(AWTEvent e)	Processes events occurring on this menu component.
void	setFont(Font f)	Sets the font to be used for this menu component to the specified font.
void	setName(String name)	Sets the name of the component to the specified string.
String	toString()	Returns a representation of this menu component as a string.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Methods declared in interface MenuContainer

getFont, postEvent

Modifier and Type	Method	Description
Font	getFont()	Returns the font in use by this container.
boolean	postEvent(Event evt)	Deprecated. As of JDK version 1.1 replaced by dispatchEvent(AWTEvent).

Constructor Details

MenuBar

public MenuBar()
        throws HeadlessException

Creates a new menu bar.

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

See Also:

• GraphicsEnvironment.isHeadless()

Method Details

addNotify

public void addNotify()

Creates the menu bar's peer. The peer allows us to change the appearance of the menu bar without changing any of the menu bar's functionality.

removeNotify

public void removeNotify()

Removes the menu bar's peer. The peer allows us to change the appearance of the menu bar without changing any of the menu bar's functionality.

Overrides:

removeNotify in class MenuComponent

getHelpMenu

public Menu getHelpMenu()

Gets the help menu on the menu bar.

Returns:

the help menu on this menu bar.

setHelpMenu

public void setHelpMenu(Menu m)

Sets the specified menu to be this menu bar's help menu. If this menu bar has an existing help menu, the old help menu is removed from the menu bar, and replaced with the specified menu.

Parameters:

m - the menu to be set as the help menu

add

public Menu add(Menu m)

Adds the specified menu to the menu bar. If the menu has been part of another menu bar, removes it from that menu bar.

Parameters:

m - the menu to be added

Returns:

the menu added

See Also:

• remove(int)
• remove(java.awt.MenuComponent)

remove

public void remove(int index)

Removes the menu located at the specified index from this menu bar.

Parameters:

index - the position of the menu to be removed.

See Also:

• add(java.awt.Menu)

remove

public void remove(MenuComponent m)

Removes the specified menu component from this menu bar.

Specified by:

remove in interface MenuContainer

Parameters:

m - the menu component to be removed.

See Also:

• add(java.awt.Menu)

getMenuCount

public int getMenuCount()

Gets the number of menus on the menu bar.

Returns:

the number of menus on the menu bar.

Since:

1.1

countMenus

@Deprecated
public int countMenus()

Deprecated.

As of JDK version 1.1, replaced by getMenuCount().

Gets the number of menus on the menu bar.

Returns:

the number of menus on the menu bar.

getMenu

public Menu getMenu(int i)

Gets the specified menu.

Parameters:

i - the index position of the menu to be returned.

Returns:

the menu at the specified index of this menu bar.

shortcuts

public Enumeration<MenuShortcut> shortcuts()

Gets an enumeration of all menu shortcuts this menu bar is managing.

Returns:

an enumeration of menu shortcuts that this menu bar is managing.

Since:

1.1

See Also:

• MenuShortcut

getShortcutMenuItem

public MenuItem getShortcutMenuItem(MenuShortcut s)

Gets the instance of MenuItem associated with the specified MenuShortcut object, or null if none of the menu items being managed by this menu bar is associated with the specified menu shortcut.

Parameters:

s - the specified menu shortcut.

Returns:

the menu item for the specified shortcut.

Since:

1.1

See Also:

• MenuItem
• MenuShortcut

deleteShortcut

public void deleteShortcut(MenuShortcut s)

Deletes the specified menu shortcut.

Parameters:

s - the menu shortcut to delete.

Since:

1.1

getAccessibleContext

public AccessibleContext getAccessibleContext()

Gets the AccessibleContext associated with this MenuBar. For menu bars, the AccessibleContext takes the form of an AccessibleAWTMenuBar. A new AccessibleAWTMenuBar instance is created if necessary.

Specified by:

getAccessibleContext in interface Accessible

Overrides:

getAccessibleContext in class MenuComponent

Returns:

an AccessibleAWTMenuBar that serves as the AccessibleContext of this MenuBar

Since:

1.3