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Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Class JMenuBar - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

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javax.swing
Class JMenuBar

java.lang.Object
  |
  +--java.awt.Component
        |
        +--java.awt.Container
              |
              +--javax.swing.JComponent
                    |
                    +--javax.swing.JMenuBar
Direct Known Subclasses:
BasicInternalFrameTitlePane.SystemMenuBar
public class JMenuBar
extends JComponent
implements Accessible, MenuElement

An implementation of a MenuBar. You add JMenu objects to the menu bar to construct a menu. When the user selects a JMenu object, its associated JPopupMenu is displayed, allowing the user to select one of the JMenuItems on it.

For the keyboard keys used by this component in the standard Look and Feel (L&F) renditions, see the JMenuBar key assignments.

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. A future release of Swing will provide support for long term persistence.

See Also:
JMenu, JPopupMenu, JMenuItem, Serialized Form

Inner Class Summary
protected  class JMenuBar.AccessibleJMenuBar
          The class used to obtain the accessible role for this object.
 
Inner classes inherited from class javax.swing.JComponent
JComponent.AccessibleJComponent
 
Fields inherited from class javax.swing.JComponent
accessibleContext, 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
BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
 
Constructor Summary
JMenuBar()
          Creates a new menu bar.
 
Method Summary
 JMenu add(JMenu c)
          Appends the specified menu to the end of the menu bar.
 void addNotify()
          Overrides JComponent.addNotify to register this menu bar with the current KeyboardManager.
 AccessibleContext getAccessibleContext()
          Get the AccessibleContext associated with this JComponent
 Component getComponent()
          Implemented to be a MenuElement.
 Component getComponentAtIndex(int i)
          Returns the component at the specified index.
 int getComponentIndex(Component c)
          Returns the index of the specified component.
 JMenu getHelpMenu()
          Gets the help menu for the menu bar.
 Insets getMargin()
          Returns the margin between the menubar's border and its menus.
 JMenu getMenu(int index)
          Gets the menu at the specified position in the menu bar.
 int getMenuCount()
          Returns the number of items in the menu bar.
 SingleSelectionModel getSelectionModel()
          Returns the model object that handles single selections.
 MenuElement[] getSubElements()
          Implemented to be a MenuElement -- returns the menus in this menu bar.
 MenuBarUI getUI()
          Returns the menubar's current UI.
 String getUIClassID()
          Returns the name of the L&F class that renders this component.
 boolean isBorderPainted()
          Returns true if the Menubar's border should be painted.
 boolean isManagingFocus()
          Returns true to indicate that this component manages focus events internally.
 boolean isSelected()
          Returns true if the MenuBar currently has a component selected
 void menuSelectionChanged(boolean isIncluded)
          Implemented to be a MenuElement -- does nothing.
protected  void paintBorder(Graphics g)
          Paint the menubar's border if BorderPainted property is true.
protected  String paramString()
          Returns a string representation of this JMenuBar.
 void processKeyEvent(KeyEvent e, MenuElement[] path, MenuSelectionManager manager)
          Implemented to be a MenuElement -- does nothing.
 void processMouseEvent(MouseEvent event, MenuElement[] path, MenuSelectionManager manager)
          Implemented to be a MenuElement -- does nothing.
 void removeNotify()
          Overrides JComponent.removeNotify to unregister this menu bar with the current KeyboardManager.
 void setBorderPainted(boolean b)
          Sets whether the border should be painted.
 void setHelpMenu(JMenu menu)
          Sets the help menu that appears when the user selects the "help" option in the menu bar.
 void setMargin(Insets m)
          Sets the margin between the menubar's border and its menus.
 void setSelected(Component sel)
          Sets the currently selected component, producing a a change to the selection model.
 void setSelectionModel(SingleSelectionModel model)
          Set the model object to handle single selections.
 void setUI(MenuBarUI ui)
          Sets the L&F object that renders this component.
 void updateUI()
          Notification from the UIFactory that the L&F has changed.
 
Methods inherited from class javax.swing.JComponent
addAncestorListener, addPropertyChangeListener, addPropertyChangeListener, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getAlignmentX, getAlignmentY, getAutoscrolls, getBorder, getBounds, getClientProperty, getComponentGraphics, getConditionForKeyStroke, getDebugGraphicsOptions, getGraphics, getHeight, getInsets, getInsets, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getVisibleRect, getWidth, getX, getY, grabFocus, hasFocus, isDoubleBuffered, isFocusCycleRoot, isFocusTraversable, isLightweightComponent, isOpaque, isOptimizedDrawingEnabled, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintChildren, paintComponent, paintImmediately, paintImmediately, processComponentKeyEvent, processFocusEvent, processKeyEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removePropertyChangeListener, removePropertyChangeListener, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setDebugGraphicsOptions, setDoubleBuffered, setEnabled, setFont, setForeground, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setUI, setVisible, unregisterKeyboardAction, update
 
Methods inherited from class java.awt.Container
add, add, add, add, add, addContainerListener, addImpl, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getLayout, insets, invalidate, isAncestorOf, layout, list, list, locate, minimumSize, paintComponents, preferredSize, print, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setCursor, setLayout, validate, validateTree
 
Methods inherited from class java.awt.Component
action, add, addComponentListener, addFocusListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, disable, disableEvents, dispatchEvent, enable, enable, enableEvents, enableInputMethods, getBackground, getBounds, getColorModel, getComponentOrientation, getCursor, getDropTarget, getFont, getFontMetrics, getForeground, getInputContext, getInputMethodRequests, getLocale, getLocation, getLocationOnScreen, getName, getParent, getPeer, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hide, imageUpdate, inside, isDisplayable, isEnabled, isLightweight, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, printAll, processComponentEvent, processInputMethodEvent, processMouseEvent, remove, removeComponentListener, removeFocusListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, repaint, repaint, repaint, resize, resize, setBounds, setBounds, setComponentOrientation, setDropTarget, setLocale, setLocation, setLocation, setName, setSize, setSize, show, show, size, toString, transferFocus
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

JMenuBar

public JMenuBar()
Creates a new menu bar.
Method Detail

getUI

public MenuBarUI getUI()
Returns the menubar's current UI.
See Also:
setUI(javax.swing.plaf.MenuBarUI)

setUI

public void setUI(MenuBarUI ui)
Sets the L&F object that renders this component.
Parameters:
ui - the new MenuBarUI L&F object
See Also:
UIDefaults.getUI(javax.swing.JComponent)

updateUI

public void updateUI()
Notification from the UIFactory that the L&F has changed. Called to replace the UI with the latest version from the UIFactory.
Overrides:
updateUI in class JComponent
See Also:
JComponent.updateUI()

getUIClassID

public String getUIClassID()
Returns the name of the L&F class that renders this component.
Overrides:
getUIClassID in class JComponent
Returns:
"MenuBarUI"
See Also:
JComponent.getUIClassID(), UIDefaults.getUI(javax.swing.JComponent)

getSelectionModel

public SingleSelectionModel getSelectionModel()
Returns the model object that handles single selections.
Returns:
the SingleSelectionModel in use
See Also:
SingleSelectionModel

setSelectionModel

public void setSelectionModel(SingleSelectionModel model)
Set the model object to handle single selections.
Parameters:
model - the SingleSelectionModel to use
See Also:
SingleSelectionModel

add

public JMenu add(JMenu c)
Appends the specified menu to the end of the menu bar.
Parameters:
c - the JMenu component to add

getMenu

public JMenu getMenu(int index)
Gets the menu at the specified position in the menu bar.
Parameters:
index - an int giving the position in the menu bar, where 0 is the first position
Returns:
the JMenu at that position

getMenuCount

public int getMenuCount()
Returns the number of items in the menu bar.
Returns:
the number of items in the menu bar

setHelpMenu

public void setHelpMenu(JMenu menu)
Sets the help menu that appears when the user selects the "help" option in the menu bar. This method is not yet implemented.
Parameters:
menu - the JMenu that delivers help to the user

getHelpMenu

public JMenu getHelpMenu()
Gets the help menu for the menu bar.
Returns:
the JMenu that delivers help to the user

getComponentAtIndex

public Component getComponentAtIndex(int i)
Returns the component at the specified index. This method is obsolete, please use getComponent(int i) instead.
Parameters:
i - an int specifying the position, where 0 = first
Returns:
the Component at the position, or null for an invalid index

getComponentIndex

public int getComponentIndex(Component c)
Returns the index of the specified component.
Parameters:
c - the Component to find
Returns:
an int giving the component's position, where 0 = first

setSelected

public void setSelected(Component sel)
Sets the currently selected component, producing a a change to the selection model.
Parameters:
sel - the Component to select

isSelected

public boolean isSelected()
Returns true if the MenuBar currently has a component selected
Returns:
true if a selection has been made, else false

isBorderPainted

public boolean isBorderPainted()
Returns true if the Menubar's border should be painted.
Returns:
true if the border should be painted, else false

setBorderPainted

public void setBorderPainted(boolean b)
Sets whether the border should be painted.
Parameters:
b - if true and border property is not null, the border is painted.
See Also:
isBorderPainted()

paintBorder

protected void paintBorder(Graphics g)
Paint the menubar's border if BorderPainted property is true.
Overrides:
paintBorder in class JComponent
Parameters:
g - the Graphics context to use for painting
See Also:
JComponent.paint(java.awt.Graphics), JComponent.setBorder(javax.swing.border.Border)

setMargin

public void setMargin(Insets m)
Sets the margin between the menubar's border and its menus. Setting to null will cause the menubar to use the default margins.
Parameters:
margin - an Insets object containing the margin values
See Also:
Insets

getMargin

public Insets getMargin()
Returns the margin between the menubar's border and its menus.
Returns:
an Insets object containing the margin values
See Also:
Insets

processMouseEvent

public void processMouseEvent(MouseEvent event,
                              MenuElement[] path,
                              MenuSelectionManager manager)
Implemented to be a MenuElement -- does nothing.
Specified by:
processMouseEvent in interface MenuElement
See Also:
getSubElements()

processKeyEvent

public void processKeyEvent(KeyEvent e,
                            MenuElement[] path,
                            MenuSelectionManager manager)
Implemented to be a MenuElement -- does nothing.
Specified by:
processKeyEvent in interface MenuElement
See Also:
getSubElements()

menuSelectionChanged

public void menuSelectionChanged(boolean isIncluded)
Implemented to be a MenuElement -- does nothing.
Specified by:
menuSelectionChanged in interface MenuElement
See Also:
getSubElements()

getSubElements

public MenuElement[] getSubElements()
Implemented to be a MenuElement -- returns the menus in this menu bar. This is the reason for implementing the MenuElement interface -- so that the menu bar can be treated the same as other menu elements.
Specified by:
getSubElements in interface MenuElement
Tags copied from interface: MenuElement
Returns:
an array of MenuElements

getComponent

public Component getComponent()
Implemented to be a MenuElement. Returns this object.
Specified by:
getComponent in interface MenuElement
Returns:
the current Component (this)
See Also:
getSubElements()

paramString

protected String paramString()
Returns a string representation of this JMenuBar. 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 JComponent
Returns:
a string representation of this JMenuBar.

getAccessibleContext

public AccessibleContext getAccessibleContext()
Get the AccessibleContext associated with this JComponent
Specified by:
getAccessibleContext in interface Accessible
Overrides:
getAccessibleContext in class JComponent
Returns:
the AccessibleContext of this JComponent

isManagingFocus

public boolean isManagingFocus()
Returns true to indicate that this component manages focus events internally.
Overrides:
isManagingFocus in class JComponent
Returns:
true

addNotify

public void addNotify()
Overrides JComponent.addNotify to register this menu bar with the current KeyboardManager.
Overrides:
addNotify in class JComponent
Tags copied from class: JComponent
See Also:
JComponent.registerKeyboardAction(java.awt.event.ActionListener, java.lang.String, javax.swing.KeyStroke, int)

removeNotify

public void removeNotify()
Overrides JComponent.removeNotify to unregister this menu bar with the current KeyboardManager.
Overrides:
removeNotify in class JComponent
Tags copied from class: JComponent
See Also:
JComponent.registerKeyboardAction(java.awt.event.ActionListener, java.lang.String, javax.swing.KeyStroke, int)
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