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
).
MenuItem
, CheckboxMenuItem
, Serialized FormModifier and Type | Class and Description |
---|---|
protected class |
Menu.AccessibleAWTMenu Inner class of Menu used to provide default support for accessibility. |
MenuItem.AccessibleAWTMenuItem
MenuComponent.AccessibleAWTMenuComponent
public Menu() throws HeadlessException
Constructs a new menu with an empty label. This menu is not a tear-off menu.
HeadlessException
- if GraphicsEnvironment.isHeadless() returns true.GraphicsEnvironment.isHeadless()
public Menu(String label) throws HeadlessException
Constructs a new menu with the specified label. This menu is not a tear-off menu.
label
- the menu's label in the menu bar, or in another menu of which this menu is a submenu.HeadlessException
- if GraphicsEnvironment.isHeadless() returns true.GraphicsEnvironment.isHeadless()
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.
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.HeadlessException
- if GraphicsEnvironment.isHeadless() returns true.GraphicsEnvironment.isHeadless()
public void addNotify()
Creates the menu's peer. The peer allows us to modify the appearance of the menu without changing its functionality.
public void removeNotify()
Removes the menu's peer. The peer allows us to modify the appearance of the menu without changing its functionality.
removeNotify
in class MenuComponent
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.
true
if this is a tear-off menu; false
otherwise.public int getItemCount()
Get the number of items in this menu.
@Deprecated public int countItems()
Deprecated. As of JDK version 1.1, replaced by getItemCount()
.
public MenuItem getItem(int index)
Gets the item located at the specified index of this menu.
index
- the position of the item to be returned.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.
mi
- the menu item to be addedinsert(java.lang.String, int)
, insert(java.awt.MenuItem, int)
public void add(String label)
Adds an item with the specified label to this menu.
label
- the text on the iteminsert(java.lang.String, int)
, insert(java.awt.MenuItem, int)
public void insert(MenuItem menuitem, int index)
Inserts a menu item into this menu at the specified position.
menuitem
- the menu item to be inserted.index
- the position at which the menu item should be inserted.IllegalArgumentException
- if the value of index
is less than zeroadd(java.lang.String)
, add(java.awt.MenuItem)
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)
.
label
- the text on the itemindex
- the position at which the menu item should be insertedIllegalArgumentException
- if the value of index
is less than zeroadd(java.lang.String)
, add(java.awt.MenuItem)
public void addSeparator()
Adds a separator line, or a hypen, to the menu at the current position.
insertSeparator(int)
public void insertSeparator(int index)
Inserts a separator at the specified position.
index
- the position at which the menu separator should be inserted.IllegalArgumentException
- if the value of index
is less than 0.addSeparator()
public void remove(int index)
Removes the menu item at the specified index from this menu.
index
- the position of the item to be removed.public void remove(MenuComponent item)
Removes the specified menu item from this menu.
remove
in interface MenuContainer
item
- the item to be removed from the menu. If item
is null
or is not in this menu, this method does nothing.public void removeAll()
Removes all items from this menu.
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
.
paramString
in class MenuItem
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.
getAccessibleContext
in interface Accessible
getAccessibleContext
in class MenuItem
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