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JDK 5 Documentation v1.1.8, Java 2 SDK 英文文档
Class java.awt.Menu - JDK 5 Documentation v1.1.8, Java 2 SDK 英文文档
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Class java.awt.Menu
java.lang.Object
|
+----java.awt.MenuComponent
|
+----java.awt.MenuItem
|
+----java.awt.Menu
- public class Menu
- extends MenuItem
- implements MenuContainer
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
).
- See Also:
- MenuItem, CheckboxMenuItem
-
Menu()
-
Constructs a new menu with an empty label.
-
Menu(String)
-
Constructs a new menu with the specified label.
-
Menu(String, boolean)
-
Constructs a new menu with the specified label.
-
add(MenuItem)
- Adds the specified menu item to this menu.
-
add(String)
- Adds an item with the specified label to this menu.
-
addNotify()
- Creates the menu's peer.
-
addSeparator()
- Adds a separator line, or a hypen, to the menu at the current position.
-
countItems()
-
Deprecated.
-
getItem(int)
- Gets the item located at the specified index of this menu.
-
getItemCount()
-
Get the number of items in this menu.
-
insert(MenuItem, int)
- Inserts a menu item into this menu
at the specified position.
-
insert(String, int)
- Inserts a menu item with the specified label into this menu
at the specified position.
-
insertSeparator(int)
- Inserts a separator at the specified position.
-
isTearOff()
- Indicates whether this menu is a tear-off menu.
-
paramString()
- Gets the parameter string representing the state of this menu.
-
remove(int)
- Removes the menu item at the specified index from this menu.
-
remove(MenuComponent)
- Removes the specified menu item from this menu.
-
removeAll()
- Removes all items from this menu.
-
removeNotify()
- Removes the menu's peer.
Menu
public Menu()
- Constructs a new menu with an empty label. This menu is not
a tear-off menu.
Menu
public Menu(String label)
- 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.
Menu
public Menu(String label,
boolean tearOff)
- Constructs a new menu with the specified label. If the
value of
tearOff
is true
,
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.
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.
countItems
public int countItems()
- Note: countItems() is 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, remove it
from that menu.
- Parameters:
- mi - the menu item to be added.
- Returns:
- the menu item added.
- See Also:
- insert, insert
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, insert
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.
- See Also:
- add, add
insert
public void insert(String label,
int index)
- Inserts a menu item with the specified label into this menu
at the specified position.
- Parameters:
- label - the text on the item.
- index - the position at which the menu item
should be inserted.
- See Also:
- add, add
addSeparator
public void addSeparator()
- Adds a separator line, or a hypen, to the menu at the current position.
- See Also:
- insertSeparator
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.
- 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.
- Parameters:
- item - the item to be removed from the menu
removeAll
public void removeAll()
- Removes all items from this menu.
paramString
public String paramString()
- Gets the parameter string representing the state of this menu.
This string is useful for debugging.
- Overrides:
- paramString in class MenuItem
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