java.awt
Class Menu

java.lang.Object
  |
  +--java.awt.MenuComponent
        |
        +--java.awt.MenuItem
              |
              +--java.awt.Menu

All Implemented Interfaces:

Accessible, MenuContainer, Serializable

Direct Known Subclasses:

PopupMenu

public class Menu

extends MenuItem

implements MenuContainer, Accessible

A Menu object is a pull-down menu component that is deployed from a menu bar.

A menu can optionally be a tear-off menu. A tear-off menu can be opened and dragged away from its parent menu bar or menu. It remains on the screen after the mouse button has been released. The mechanism for tearing off a menu is platform dependent, since the look and feel of the tear-off menu is determined by its peer. On platforms that do not support tear-off menus, the tear-off property is ignored.

Each item in a menu must belong to the MenuItem class. It can be an instance of MenuItem, a submenu (an instance of Menu), or a check box (an instance of CheckboxMenuItem).

Since:

JDK1.0

See Also:

MenuItem, CheckboxMenuItem, Serialized Form

Nested Class Summary

protected class

Menu.AccessibleAWTMenu Inner class of Menu used to provide default support for accessibility.

Nested classes inherited from class java.awt.MenuItem

Nested classes inherited from class java.awt.MenuComponent

Constructor Summary

Menu()
Constructs a new menu with an empty label.

Menu(String label)
Constructs a new menu with the specified label.

Menu(String label, boolean tearOff)
Constructs a new menu with the specified label, indicating whether the menu can be torn off.

Method Summary

MenuItem	add(MenuItem mi) Adds the specified menu item to this menu.
void	add(String label) Adds an item with the specified label to this menu.
void	addNotify() Creates the menu's peer.
void	addSeparator() Adds a separator line, or a hypen, to the menu at the current position.
int	countItems() Deprecated. As of JDK version 1.1, replaced by getItemCount().
AccessibleContext	getAccessibleContext() Gets the AccessibleContext associated with this Menu.
MenuItem	getItem(int index) Gets the item located at the specified index of this menu.
int	getItemCount() Get the number of items in this menu.
void	insert(MenuItem menuitem, int index) Inserts a menu item into this menu at the specified position.
void	insert(String label, int index) Inserts a menu item with the specified label into this menu at the specified position.
void	insertSeparator(int index) Inserts a separator at the specified position.
boolean	isTearOff() Indicates whether this menu is a tear-off menu.
String	paramString() Returns a string representing the state of this Menu.
void	remove(int index) Removes the menu item at the specified index from this menu.
void	remove(MenuComponent item) Removes the specified menu item from this menu.
void	removeAll() Removes all items from this menu.
void	removeNotify() Removes the menu's peer.

Methods inherited from class java.awt.MenuItem

addActionListener, deleteShortcut, disable, disableEvents, enable, enable, enableEvents, getActionCommand, getActionListeners, getLabel, getListeners, getShortcut, isEnabled, processActionEvent, processEvent, removeActionListener, setActionCommand, setEnabled, setLabel, setShortcut

Methods inherited from class java.awt.MenuComponent

dispatchEvent, getFont, getName, getParent, getPeer, getTreeLock, postEvent, setFont, setName, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.awt.MenuContainer

getFont, postEvent

Constructor Detail

Menu

public Menu()
     throws HeadlessException

Constructs a new menu with an empty label. This menu is not a tear-off menu.

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

Since:

JDK1.1

See Also:

GraphicsEnvironment.isHeadless()

Menu

public Menu(String label)
     throws HeadlessException

Constructs a new menu with the specified label. This menu is not a tear-off menu.

Parameters:

label - the menu's label in the menu bar, or in another menu of which this menu is a submenu.

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

See Also:

GraphicsEnvironment.isHeadless()

Menu

public Menu(String label,
            boolean tearOff)
     throws HeadlessException

Constructs a new menu with the specified label, indicating whether the menu can be torn off.

Tear-off functionality may not be supported by all implementations of AWT. If a particular implementation doesn't support tear-off menus, this value is silently ignored.

Parameters:

label - the menu's label in the menu bar, or in another menu of which this menu is a submenu.

tearOff - if true, the menu is a tear-off menu.

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

Since:

JDK1.0.

See Also:

GraphicsEnvironment.isHeadless()

Method Detail

addNotify

public void addNotify()

Creates the menu's peer. The peer allows us to modify the appearance of the menu without changing its functionality.

Overrides:

addNotify in class MenuItem

removeNotify

public void removeNotify()

Removes the menu's peer. The peer allows us to modify the appearance of the menu without changing its functionality.

Overrides:

removeNotify in class MenuComponent

isTearOff

public boolean isTearOff()

Indicates whether this menu is a tear-off menu.

Tear-off functionality may not be supported by all implementations of AWT. If a particular implementation doesn't support tear-off menus, this value is silently ignored.

Returns:

true if this is a tear-off menu; false otherwise.

getItemCount

public int getItemCount()

Get the number of items in this menu.

Returns:

the number of items in this menu.

Since:

JDK1.1

countItems

public int countItems()

Deprecated. As of JDK version 1.1, replaced by getItemCount().

getItem

public MenuItem getItem(int index)

Gets the item located at the specified index of this menu.

Parameters:

index - the position of the item to be returned.

Returns:

the item located at the specified index.

add

public MenuItem add(MenuItem mi)

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

Parameters:

mi - the menu item to be added

Returns:

the menu item added

See Also:

insert(java.lang.String, int), insert(java.awt.MenuItem, int)

add

public void add(String label)

Adds an item with the specified label to this menu.

Parameters:

label - the text on the item

See Also:

insert(java.lang.String, int), insert(java.awt.MenuItem, int)

insert

public void insert(MenuItem menuitem,
                   int index)

Inserts a menu item into this menu at the specified position.

Parameters:

menuitem - the menu item to be inserted.

index - the position at which the menu item should be inserted.

Throws:

IllegalArgumentException - if the value of index is less than zero

Since:

JDK1.1

See Also:

add(java.lang.String), add(java.awt.MenuItem)

insert

public void insert(String label,
                   int index)

Inserts a menu item with the specified label into this menu at the specified position. This is a convenience method for insert(menuItem, index).

Parameters:

label - the text on the item

index - the position at which the menu item should be inserted

Throws:

IllegalArgumentException - if the value of index is less than zero

Since:

JDK1.1

See Also:

add(java.lang.String), add(java.awt.MenuItem)

addSeparator

public void addSeparator()

Adds a separator line, or a hypen, to the menu at the current position.

See Also:

insertSeparator(int)

insertSeparator

public void insertSeparator(int index)

Inserts a separator at the specified position.

Parameters:

index - the position at which the menu separator should be inserted.

Throws:

IllegalArgumentException - if the value of index is less than 0.

Since:

JDK1.1

See Also:

addSeparator()

remove

public void remove(int index)

Removes the menu item at the specified index from this menu.

Parameters:

index - the position of the item to be removed.

remove

public void remove(MenuComponent item)

Removes the specified menu item from this menu.

Specified by:

remove in interface MenuContainer

Parameters:

item - the item to be removed from the menu. If item is null or is not in this menu, this method does nothing.

removeAll

public void removeAll()

Removes all items from this menu.

Since:

JDK1.0.

paramString

public String paramString()

Returns a string representing the state of this Menu. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be null.

Overrides:

paramString in class MenuItem

Returns:

the parameter string of this menu

getAccessibleContext

public AccessibleContext getAccessibleContext()

Gets the AccessibleContext associated with this Menu. For menus, the AccessibleContext takes the form of an AccessibleAWTMenu. A new AccessibleAWTMenu instance is created if necessary.

Specified by:

getAccessibleContext in interface Accessible

Overrides:

getAccessibleContext in class MenuItem

Returns:

an AccessibleAWTMenu that serves as the AccessibleContext of this Menu