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Class JMenuItem

java.lang.Object
- java.awt.Component
- - java.awt.Container
  - - javax.swing.JComponent
    - - javax.swing.AbstractButton
      - javax.swing.JMenuItem

All Implemented Interfaces:: ImageObserver, ItemSelectable, MenuContainer, Serializable, Accessible, MenuElement, SwingConstants

Direct Known Subclasses:: JCheckBoxMenuItem, JMenu, JRadioButtonMenuItem

public class JMenuItem
extends AbstractButton
implements Accessible, MenuElement

An implementation of an item in a menu. A menu item is essentially a button sitting in a list. When the user selects the "button", the action associated with the menu item is performed. A JMenuItem contained in a JPopupMenu performs exactly that function.

Menu items can be configured, and to some degree controlled, by Actions. Using an Action with a menu item has many benefits beyond directly configuring a menu item. Refer to Swing Components Supporting Action for more details, and you can find more information in How to Use Actions, a section in The Java Tutorial.

For further documentation and for examples, see How to Use Menus in The Java Tutorial.

Warning: Swing is not thread safe. For more information see Swing's Threading Policy.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans™ has been added to the java.beans package. Please see XMLEncoder.

See Also:: JPopupMenu, JMenu, JCheckBoxMenuItem, JRadioButtonMenuItem

Nested Classes

Nested Classes
Modifier and Type	Class and Description
`protected class`	`JMenuItem.AccessibleJMenuItem` This class implements accessibility support for the `JMenuItem` class.

Nested classes/interfaces inherited from class javax.swing.AbstractButton

AbstractButton.AccessibleAbstractButton, AbstractButton.ButtonChangeListener

Nested classes/interfaces inherited from class javax.swing.JComponent

JComponent.AccessibleJComponent

Nested classes/interfaces inherited from class java.awt.Container

Container.AccessibleAWTContainer

Nested classes/interfaces inherited from class java.awt.Component

Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy

Fields

Fields inherited from class javax.swing.AbstractButton

actionListener, BORDER_PAINTED_CHANGED_PROPERTY, changeEvent, changeListener, CONTENT_AREA_FILLED_CHANGED_PROPERTY, DISABLED_ICON_CHANGED_PROPERTY, DISABLED_SELECTED_ICON_CHANGED_PROPERTY, FOCUS_PAINTED_CHANGED_PROPERTY, HORIZONTAL_ALIGNMENT_CHANGED_PROPERTY, HORIZONTAL_TEXT_POSITION_CHANGED_PROPERTY, ICON_CHANGED_PROPERTY, itemListener, MARGIN_CHANGED_PROPERTY, MNEMONIC_CHANGED_PROPERTY, model, MODEL_CHANGED_PROPERTY, PRESSED_ICON_CHANGED_PROPERTY, ROLLOVER_ENABLED_CHANGED_PROPERTY, ROLLOVER_ICON_CHANGED_PROPERTY, ROLLOVER_SELECTED_ICON_CHANGED_PROPERTY, SELECTED_ICON_CHANGED_PROPERTY, TEXT_CHANGED_PROPERTY, VERTICAL_ALIGNMENT_CHANGED_PROPERTY, VERTICAL_TEXT_POSITION_CHANGED_PROPERTY

Fields inherited from class javax.swing.JComponent

listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW

Fields inherited from class java.awt.Component

accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields inherited from interface javax.swing.SwingConstants

BOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST

Fields inherited from interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructors

JMenuItem

public JMenuItem()

Creates a JMenuItem with no set text or icon.

JMenuItem

public JMenuItem(Icon icon)

Creates a JMenuItem with the specified icon.

Parameters:: icon - the icon of the JMenuItem

JMenuItem

public JMenuItem(String text)

Creates a JMenuItem with the specified text.

Parameters:: text - the text of the JMenuItem

JMenuItem

public JMenuItem(Action a)

Creates a menu item whose properties are taken from the specified Action.

Parameters:: a - the action of the JMenuItem
Since:: 1.3

JMenuItem

public JMenuItem(String text,
                 Icon icon)

Creates a JMenuItem with the specified text and icon.

Parameters:: text - the text of the JMenuItem; icon - the icon of the JMenuItem

JMenuItem

public JMenuItem(String text,
                 int mnemonic)

Creates a JMenuItem with the specified text and keyboard mnemonic.

Parameters:: text - the text of the JMenuItem; mnemonic - the keyboard mnemonic for the JMenuItem

Methods

setModel

public void setModel(ButtonModel newModel)

Sets the model that this button represents.

Overrides:: setModel in class AbstractButton
Parameters:: newModel - the new ButtonModel
See Also:: AbstractButton.getModel()

init

protected void init(String text,
                    Icon icon)

Initializes the menu item with the specified text and icon.

Overrides:: init in class AbstractButton
Parameters:: text - the text of the JMenuItem; icon - the icon of the JMenuItem

setUI

public void setUI(MenuItemUI ui)

Sets the look and feel object that renders this component.

Parameters:: ui - the JMenuItemUI L&F object
See Also:: UIDefaults.getUI(javax.swing.JComponent)

updateUI

public void updateUI()

Resets the UI property with a value from the current look and feel.

Overrides:: updateUI in class AbstractButton
See Also:: JComponent.updateUI()

getUIClassID

public String getUIClassID()

Returns the suffix used to construct the name of the L&F class used to render this component.

Overrides:: getUIClassID in class JComponent
Returns:: the string "MenuItemUI"
See Also:: JComponent.getUIClassID(), UIDefaults.getUI(javax.swing.JComponent)

setArmed

public void setArmed(boolean b)

Identifies the menu item as "armed". If the mouse button is released while it is over this item, the menu's action event will fire. If the mouse button is released elsewhere, the event will not fire and the menu item will be disarmed.

Parameters:: b - true to arm the menu item so it can be selected

isArmed

public boolean isArmed()

Returns whether the menu item is "armed".

Returns:: true if the menu item is armed, and it can be selected
See Also:: setArmed(boolean)

setEnabled

public void setEnabled(boolean b)

Enables or disables the menu item.

Overrides:: setEnabled in class AbstractButton
Parameters:: b - true to enable the item
See Also:: Component.isEnabled(), Component.isLightweight()

setAccelerator

public void setAccelerator(KeyStroke keyStroke)

Sets the key combination which invokes the menu item's action listeners without navigating the menu hierarchy. It is the UI's responsibility to install the correct action. Note that when the keyboard accelerator is typed, it will work whether or not the menu is currently displayed.

Parameters:: keyStroke - the KeyStroke which will serve as an accelerator

getAccelerator

public KeyStroke getAccelerator()

Returns the KeyStroke which serves as an accelerator for the menu item.

Returns:: a KeyStroke object identifying the accelerator key

configurePropertiesFromAction

protected void configurePropertiesFromAction(Action a)

Sets the properties on this button to match those in the specified Action. Refer to Swing Components Supporting Action for more details as to which properties this sets.

Overrides:: configurePropertiesFromAction in class AbstractButton
Parameters:: a - the Action from which to get the properties, or null
Since:: 1.3
See Also:: Action, AbstractButton.setAction(javax.swing.Action)

actionPropertyChanged

protected void actionPropertyChanged(Action action,
                                     String propertyName)

Updates the button's state in response to property changes in the associated action. This method is invoked from the PropertyChangeListener returned from createActionPropertyChangeListener. Subclasses do not normally need to invoke this. Subclasses that support additional Action properties should override this and configurePropertiesFromAction.

Refer to the table at Swing Components Supporting Action for a list of the properties this method sets.

Overrides:: actionPropertyChanged in class AbstractButton
Parameters:: action - the Action associated with this button; propertyName - the name of the property that changed
Since:: 1.6
See Also:: Action, AbstractButton.configurePropertiesFromAction(javax.swing.Action)

processMouseEvent

public void processMouseEvent(MouseEvent e,
                              MenuElement[] path,
                              MenuSelectionManager manager)

Processes a mouse event forwarded from the MenuSelectionManager and changes the menu selection, if necessary, by using the MenuSelectionManager's API.

Note: you do not have to forward the event to sub-components. This is done automatically by the MenuSelectionManager.

Specified by:: processMouseEvent in interface MenuElement
Parameters:: e - a MouseEvent; path - the MenuElement path array; manager - the MenuSelectionManager

processKeyEvent

public void processKeyEvent(KeyEvent e,
                            MenuElement[] path,
                            MenuSelectionManager manager)

Processes a key event forwarded from the MenuSelectionManager and changes the menu selection, if necessary, by using MenuSelectionManager's API.

Note: you do not have to forward the event to sub-components. This is done automatically by the MenuSelectionManager.

Specified by:: processKeyEvent in interface MenuElement
Parameters:: e - a KeyEvent; path - the MenuElement path array; manager - the MenuSelectionManager

processMenuDragMouseEvent

public void processMenuDragMouseEvent(MenuDragMouseEvent e)

Handles mouse drag in a menu.

Parameters:: e - a MenuDragMouseEvent object

processMenuKeyEvent

public void processMenuKeyEvent(MenuKeyEvent e)

Handles a keystroke in a menu.

Parameters:: e - a MenuKeyEvent object