JavaTM 2 Platform
Std. Ed. v1.3.1

javax.swing
Class JComboBox

java.lang.Object
  |
  +--java.awt.Component
        |
        +--java.awt.Container
              |
              +--javax.swing.JComponent
                    |
                    +--javax.swing.JComboBox
All Implemented Interfaces:
Accessible, ActionListener, EventListener, ImageObserver, ItemSelectable, ListDataListener, MenuContainer, Serializable

public class JComboBox
extends JComponent
implements ItemSelectable, ListDataListener, ActionListener, Accessible

A component that combines a button or text field and a drop-down list. The user can select a value from the drop-down list, which appears at the user's request. If you make the combo box editable, then the combo box includes a text field into which the user can type a value. For examples and information on using combo boxes see How to Use Combo Boxes, a section in The Java Tutorial.

For the keyboard keys used by this component in the standard Look and Feel (L&F) renditions, see the JComboBox 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:
Serialized Form

Inner Class Summary
protected  class JComboBox.AccessibleJComboBox
          This class implements accessibility support for the JComboBox class.
static interface JComboBox.KeySelectionManager
          The interface that defines a KeySelectionManager.
 
Inner classes inherited from class javax.swing.JComponent
JComponent.AccessibleJComponent
 
Inner classes inherited from class java.awt.Container
Container.AccessibleAWTContainer
 
Inner classes inherited from class java.awt.Component
Component.AccessibleAWTComponent
 
Field Summary
protected  String actionCommand
           
protected  ComboBoxModel dataModel
           
protected  ComboBoxEditor editor
           
protected  boolean isEditable
           
protected  JComboBox.KeySelectionManager keySelectionManager
           
protected  boolean lightWeightPopupEnabled
           
protected  int maximumRowCount
           
protected  ListCellRenderer renderer
           
protected  Object selectedItemReminder
           
 
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
 
Fields inherited from interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
 
Constructor Summary
JComboBox()
          Creates a JComboBox with a default data model.
JComboBox(ComboBoxModel aModel)
          Creates a JComboBox that takes it's items from an existing ComboBoxModel.
JComboBox(Object[] items)
          Creates a JComboBox that contains the elements in the specified array.
JComboBox(Vector items)
          Creates a JComboBox that contains the elements in the specified Vector.
 
Method Summary
 void actionPerformed(ActionEvent e)
          This method is public as an implementation side effect.
 void addActionListener(ActionListener l)
          Adds an ActionListener.
 void addItem(Object anObject)
          Adds an item to the item list.
 void addItemListener(ItemListener aListener)
          Adds an ItemListener.
 void configureEditor(ComboBoxEditor anEditor, Object anItem)
          Initializes the editor with the specified item.
protected  void configurePropertiesFromAction(Action a)
          Factory method which sets the ActionEvent source's properties according to values from the Action instance.
 void contentsChanged(ListDataEvent e)
          This method is public as an implementation side effect.
protected  PropertyChangeListener createActionPropertyChangeListener(Action a)
          Factory method which creates the PropertyChangeListener used to update the ActionEvent source as properties change on its Action instance.
protected  JComboBox.KeySelectionManager createDefaultKeySelectionManager()
          Returns an instance of the default key-selection manager.
protected  void fireActionEvent()
          Notifies all listeners that have registered interest for notification on this event type.
protected  void fireItemStateChanged(ItemEvent e)
          Notifies all listeners that have registered interest for notification on this event type.
 AccessibleContext getAccessibleContext()
          Gets the AccessibleContext associated with this JComboBox.
 Action getAction()
          Returns the currently set Action for this ActionEvent source, or null if no Action is set.
 String getActionCommand()
          Returns the action command that is included in the event sent to action listeners.
 ComboBoxEditor getEditor()
          Returns the editor used to paint and edit the selected item in the JComboBox field.
 Object getItemAt(int index)
          Returns the list item at the specified index.
 int getItemCount()
          Returns the number of items in the list.
 JComboBox.KeySelectionManager getKeySelectionManager()
          Returns the list's key-selection manager.
 int getMaximumRowCount()
          Returns the maximum number of items the combo box can display without a scrollbar
 ComboBoxModel getModel()
          Returns the data model currently used by the JComboBox.
 ListCellRenderer getRenderer()
          Returns the renderer used to display the selected item in the JComboBox field.
 int getSelectedIndex()
          Returns the first item in the list that matches the given item.
 Object getSelectedItem()
          Returns the currently selected item.
 Object[] getSelectedObjects()
          Returns an array containing the selected item.
 ComboBoxUI getUI()
          Returns the L&F object that renders this component.
 String getUIClassID()
          Returns the name of the L&F class that renders this component.
 void hidePopup()
          Causes the combo box to close its popup window.
 void insertItemAt(Object anObject, int index)
          Inserts an item into the item list at a given index.
protected  void installAncestorListener()
           
 void intervalAdded(ListDataEvent e)
          Invoked items have been added to the internal data model.
 void intervalRemoved(ListDataEvent e)
          Invoked when values have been removed from the data model.
 boolean isEditable()
          Returns true if the JComboBox is editable.
 boolean isFocusTraversable()
          Returns true if the component can receive the focus.
 boolean isLightWeightPopupEnabled()
          Returns true if lightweight (all-Java) popups are in use, or false if heavyweight (native peer) popups are being used.
 boolean isPopupVisible()
          Determines the visibility of the popup.
protected  String paramString()
          Returns a string representation of this JComboBox.
 void processKeyEvent(KeyEvent e)
          Handles KeyEvents, looking for the Tab key.
 void removeActionListener(ActionListener l)
          Removes an ActionListener.
 void removeAllItems()
          Removes all items from the item list.
 void removeItem(Object anObject)
          Removes an item from the item list.
 void removeItemAt(int anIndex)
          Removes the item at anIndex This method works only if the JComboBox uses the default data model.
 void removeItemListener(ItemListener aListener)
          Removes an ItemListener.
protected  void selectedItemChanged()
          This method is called when the selected item changes.
 boolean selectWithKeyChar(char keyChar)
          Selects the list item that correponds to the specified keyboard character and returns true, if there is an item corresponding to that character.
 void setAction(Action a)
          Sets the Action for the ActionEvent source.
 void setActionCommand(String aCommand)
          Sets the action commnand that should be included in the event sent to action listeners.
 void setEditable(boolean aFlag)
          Determines whether the JComboBox field is editable.
 void setEditor(ComboBoxEditor anEditor)
          Sets the editor used to paint and edit the selected item in the JComboBox field.
 void setEnabled(boolean b)
          Enables the combo box so that items can be selected.
 void setKeySelectionManager(JComboBox.KeySelectionManager aManager)
          Sets the object that translates a keyboard character into a list selection.
 void setLightWeightPopupEnabled(boolean aFlag)
          When displaying the popup, JComboBox choose to use a light weight popup if it fits.
 void setMaximumRowCount(int count)
          Sets the maximum number of rows the JComboBox displays.
 void setModel(ComboBoxModel aModel)
          Sets the data model that the JComboBox uses to obtain the list of items.
 void setPopupVisible(boolean v)
          Sets the visibility of the popup.
 void setRenderer(ListCellRenderer aRenderer)
          Sets the renderer that paints the item selected from the list in the JComboBox field.
 void setSelectedIndex(int anIndex)
          Selects the item at index anIndex.
 void setSelectedItem(Object anObject)
          Sets the selected item in the JComboBox by specifying the object in the list.
 void setUI(ComboBoxUI ui)
          Sets the L&F object that renders this component.
 void showPopup()
          Causes the combo box to display its popup window.
 void updateUI()
          Notification from the UIFactory that the L&F has changed.
 
Methods inherited from class javax.swing.JComponent
addAncestorListener, addNotify, addPropertyChangeListener, addPropertyChangeListener, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAutoscrolls, getBorder, getBounds, getClientProperty, getComponentGraphics, getConditionForKeyStroke, getDebugGraphicsOptions, getGraphics, getHeight, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getVerifyInputWhenFocusTarget, getVisibleRect, getWidth, getX, getY, grabFocus, hasFocus, hide, isDoubleBuffered, isFocusCycleRoot, isLightweightComponent, isManagingFocus, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isOptimizedDrawingEnabled, isPaintingTile, isPreferredSizeSet, isRequestFocusEnabled, isValidateRoot, paint, paintBorder, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processFocusEvent, processKeyBinding, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setDebugGraphicsOptions, setDoubleBuffered, setFont, setForeground, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setUI, setVerifyInputWhenFocusTarget, 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, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setLayout, validate, validateTree
 
Methods inherited from class java.awt.Component
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, getBackground, getBounds, getColorModel, getComponentOrientation, getCursor, getDropTarget, getFont, getFontMetrics, getForeground, getGraphicsConfiguration, getInputContext, getInputMethodRequests, getLocale, getLocation, getLocationOnScreen, getName, getParent, getPeer, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, 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, processComponentEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, repaint, repaint, repaint, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, 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
 

Field Detail

dataModel

protected ComboBoxModel dataModel

renderer

protected ListCellRenderer renderer

editor

protected ComboBoxEditor editor

maximumRowCount

protected int maximumRowCount

isEditable

protected boolean isEditable

selectedItemReminder

protected Object selectedItemReminder

keySelectionManager

protected JComboBox.KeySelectionManager keySelectionManager

actionCommand

protected String actionCommand

lightWeightPopupEnabled

protected boolean lightWeightPopupEnabled
Constructor Detail

JComboBox

public JComboBox(ComboBoxModel aModel)
Creates a JComboBox that takes it's items from an existing ComboBoxModel. Since the ComboBoxModel is provided, a combo box created using this constructor does not create a default combo box model and may impact how the insert, remove and add methods behave.
Parameters:
aModel - the ComboBoxModel that provides the displayed list of items
See Also:
DefaultComboBoxModel

JComboBox

public JComboBox(Object[] items)
Creates a JComboBox that contains the elements in the specified array. By default the first item in the array (and therefore the data model) becomes selected.
Parameters:
items - an array of objects to insert into the combo box
See Also:
DefaultComboBoxModel

JComboBox

public JComboBox(Vector items)
Creates a JComboBox that contains the elements in the specified Vector. By default the first item in the vector and therefore the data model) becomes selected.
Parameters:
items - an array of vectors to insert into the combo box
See Also:
DefaultComboBoxModel

JComboBox

public JComboBox()
Creates a JComboBox with a default data model. The default data model is an empty list of objects. Use addItem to add items. By default the first item in the data model becomes selected.
See Also:
DefaultComboBoxModel
Method Detail

installAncestorListener

protected void installAncestorListener()

setUI

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

updateUI

public void updateUI()
Notification from the UIFactory that the L&F has changed.
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:
the string "ComboBoxUI"
See Also:
JComponent.getUIClassID(), UIDefaults.getUI(javax.swing.JComponent)

getUI

public ComboBoxUI getUI()
Returns the L&F object that renders this component.
Returns:
the ComboBoxUI object that renders this component

setModel

public void setModel(ComboBoxModel aModel)
Sets the data model that the JComboBox uses to obtain the list of items.
Parameters:
aModel - the ComboBoxModel that provides the displayed list of items

getModel

public ComboBoxModel getModel()
Returns the data model currently used by the JComboBox.
Returns:
the ComboBoxModel that provides the displayed list of items

setLightWeightPopupEnabled

public void setLightWeightPopupEnabled(boolean aFlag)
When displaying the popup, JComboBox choose to use a light weight popup if it fits. This method allows you to disable this feature. You have to do disable it if your application mixes light weight and heavy weights components.

isLightWeightPopupEnabled

public boolean isLightWeightPopupEnabled()
Returns true if lightweight (all-Java) popups are in use, or false if heavyweight (native peer) popups are being used.
Returns:
true if lightweight popups are in use

setEditable

public void setEditable(boolean aFlag)
Determines whether the JComboBox field is editable. An editable JComboBox allows the user to type into the field or selected an item from the list to initialize the field, after which it can be edited. (The editing affects only the field, the list item remains intact.) A non editable JComboBox displays the selected item in the field, but the selection cannot be modified.
Parameters:
aFlag - a boolean value, where true indicates that the field is editable

isEditable

public boolean isEditable()
Returns true if the JComboBox is editable. By default, a combo box is not editable.
Returns:
true if the JComboBox is editable, else false

setMaximumRowCount

public void setMaximumRowCount(int count)
Sets the maximum number of rows the JComboBox displays. If the number of objects in the model is greater than count, the combo box uses a scrollbar.
Parameters:
count - an integer specifying the maximum number of items to display in the list before using a scrollbar

getMaximumRowCount

public int getMaximumRowCount()
Returns the maximum number of items the combo box can display without a scrollbar
Returns:
an integer specifying the maximum number of items that are displayed in the list before using a scrollbar

setRenderer

public void setRenderer(ListCellRenderer aRenderer)
Sets the renderer that paints the item selected from the list in the JComboBox field. The renderer is used if the JComboBox is not editable. If it is editable, the editor is used to render and edit the selected item.

The default renderer displays a string, obtained by calling the selected object's toString method. Other renderers can handle graphic images and composite items.

To display the selected item, aRenderer.getListCellRendererComponent is called, passing the list object and an index of -1.

Parameters:
aRenderer - the ListCellRenderer that displays the selected item
See Also:
setEditor(javax.swing.ComboBoxEditor)

getRenderer

public ListCellRenderer getRenderer()
Returns the renderer used to display the selected item in the JComboBox field.
Returns:
the ListCellRenderer that displays the selected item.

setEditor

public void setEditor(ComboBoxEditor anEditor)
Sets the editor used to paint and edit the selected item in the JComboBox field. The editor is used only if the receiving JComboBox is editable. If not editable, the combo box uses the renderer to paint the selected item.
Parameters:
anEditor - the ComboBoxEditor that displays the selected item
See Also:
setRenderer(javax.swing.ListCellRenderer)

getEditor

public ComboBoxEditor getEditor()
Returns the editor used to paint and edit the selected item in the JComboBox field.
Returns:
the ComboBoxEditor that displays the selected item

setSelectedItem

public void setSelectedItem(Object anObject)
Sets the selected item in the JComboBox by specifying the object in the list. If anObject is in the list, the list displays with anObject selected.
Parameters:
anObject - the list object to select

getSelectedItem

public Object getSelectedItem()
Returns the currently selected item.
Returns:
the currently selected list object from the data model

setSelectedIndex

public void setSelectedIndex(int anIndex)
Selects the item at index anIndex.
Parameters:
anIndex - an integer specifying the list item to select, where 0 specifies the first item in the list
Throws:
IllegalArgumentException - if anIndex < -1 or anIndex is greater than or equal to size

getSelectedIndex

public int getSelectedIndex()
Returns the first item in the list that matches the given item. The result is not always defined if the JComboBox allows selected items that are not in the list. Returns -1 if there is no selected item or if the user specified an item which is not in the list.
Returns:
an integer specifying the currently selected list item, where 0 specifies the first item in the list; or -1 if no item is selected or if the currently selected item is not in the list

addItem

public void addItem(Object anObject)
Adds an item to the item list. This method works only if the JComboBox uses the default data model. JComboBox uses the default data model when created with the empty constructor and no other model has been set.

Warning: Focus and keyboard navigation problems may arise if you add duplicate String objects. A workaround is to add new objects instead of String objects and make sure that the toString() method is defined. For example:

   comboBox.addItem(makeObj("Item 1"));
   comboBox.addItem(makeObj("Item 1"));
   ...
   private Object makeObj(final String item)  {
     return new Object() { public String toString() { return item; } };
   }
 
Parameters:
anObject - the Object to add to the list

insertItemAt

public void insertItemAt(Object anObject,
                         int index)
Inserts an item into the item list at a given index. This method works only if the JComboBox uses the default data model. JComboBox uses the default data model when created with the empty constructor and no other model has been set.
Parameters:
anObject - the Object to add to the list
index - an integer specifying the position at which to add the item

removeItem

public void removeItem(Object anObject)
Removes an item from the item list. This method works only if the JComboBox uses the default data model. JComboBox uses the default data model when created with the empty constructor and no other model has been set.
Parameters:
anObject - the object to remove from the item list

removeItemAt

public void removeItemAt(int anIndex)
Removes the item at anIndex This method works only if the JComboBox uses the default data model. JComboBox uses the default data model when created with the empty constructor and no other model has been set.
Parameters:
anIndex - an int specifying the idex of the item to remove, where 0 indicates the first item in the list

removeAllItems

public void removeAllItems()
Removes all items from the item list.

showPopup

public void showPopup()
Causes the combo box to display its popup window.
See Also:
setPopupVisible(boolean)

hidePopup

public void hidePopup()
Causes the combo box to close its popup window.
See Also:
setPopupVisible(boolean)

setPopupVisible

public void setPopupVisible(boolean v)
Sets the visibility of the popup.

isPopupVisible

public boolean isPopupVisible()
Determines the visibility of the popup.

addItemListener

public void addItemListener(ItemListener aListener)
Adds an ItemListener. aListener will receive an event when the selected item changes.
Specified by:
addItemListener in interface ItemSelectable
Parameters:
aListener - the ItemListener that is to be notified

removeItemListener

public void removeItemListener(ItemListener aListener)
Removes an ItemListener.
Specified by:
removeItemListener in interface ItemSelectable
Parameters:
aListener - the ItemListener to remove

addActionListener

public void addActionListener(ActionListener l)
Adds an ActionListener. The listener will receive an action event the user finishes making a selection.
Parameters:
l - the ActionListener that is to be notified

removeActionListener

public void removeActionListener(ActionListener l)
Removes an ActionListener.
Parameters:
l - the ActionListener to remove

setActionCommand

public void setActionCommand(String aCommand)
Sets the action commnand that should be included in the event sent to action listeners.
Parameters:
aCommand - a string containing the "command" that is sent to action listeners; the same listener can then do different things depending on the command it receives

getActionCommand

public String getActionCommand()
Returns the action command that is included in the event sent to action listeners.
Returns:
the string containing the "command" that is sent to action listeners.

setAction

public void setAction(Action a)
Sets the Action for the ActionEvent source. The new Action replaces any previously set Action but does not affect ActionListeners independantly added with addActionListener. If the Action is already a registered ActionListener for the ActionEvent source, it is not re-registered.

A side-effect of setting the Action is that the ActionEvent source's properties are immedately set from the values in the Action (performed by the method configurePropertiesFromAction) and subsequently updated as the Action's properties change (via a PropertyChangeListener created by the method createActionPropertyChangeListener.

Parameters:
a - the Action for the JComboBox, or null.
Since:
1.3
See Also:
Action, getAction(), configurePropertiesFromAction(javax.swing.Action), createActionPropertyChangeListener(javax.swing.Action)

getAction

public Action getAction()
Returns the currently set Action for this ActionEvent source, or null if no Action is set.
Returns:
the Action for this ActionEvent source; or null
Since:
1.3
See Also:
Action, setAction(javax.swing.Action)

configurePropertiesFromAction

protected void configurePropertiesFromAction(Action a)
Factory method which sets the ActionEvent source's properties according to values from the Action instance. The properties which are set may differ for subclasses. By default, the properties which get set are Enabled and ToolTipText.
Parameters:
a - the Action from which to get the properties, or null
Since:
1.3
See Also:
Action, setAction(javax.swing.Action)

createActionPropertyChangeListener

protected PropertyChangeListener createActionPropertyChangeListener(Action a)
Factory method which creates the PropertyChangeListener used to update the ActionEvent source as properties change on its Action instance. Subclasses may override this in order to provide their own PropertyChangeListener if the set of properties which should be kept up to date differs from the default properties (Text, Icon, Enabled, ToolTipText). Note that PropertyChangeListeners should avoid holding strong references to the ActionEvent source, as this may hinder garbage collection of the ActionEvent source and all components in its containment hierarchy.
Since:
1.3
See Also:
Action, setAction(javax.swing.Action)

fireItemStateChanged

protected void fireItemStateChanged(ItemEvent e)
Notifies all listeners that have registered interest for notification on this event type.
Parameters:
e - the event of interest
See Also:
EventListenerList

fireActionEvent

protected void fireActionEvent()
Notifies all listeners that have registered interest for notification on this event type.
Parameters:
e - the event of interest
See Also:
EventListenerList

selectedItemChanged

protected void selectedItemChanged()
This method is called when the selected item changes. Its default implementation notifies the item listeners.

getSelectedObjects

public Object[] getSelectedObjects()
Returns an array containing the selected item. This method is implemented for compatibility with ItemSelectable.
Specified by:
getSelectedObjects in interface ItemSelectable

actionPerformed

public void actionPerformed(ActionEvent e)
This method is public as an implementation side effect. do not call or override.
Specified by:
actionPerformed in interface ActionListener

contentsChanged

public void contentsChanged(ListDataEvent e)
This method is public as an implementation side effect. do not call or override.
Specified by:
contentsChanged in interface ListDataListener
See Also:
ListDataListener

selectWithKeyChar

public boolean selectWithKeyChar(char keyChar)
Selects the list item that correponds to the specified keyboard character and returns true, if there is an item corresponding to that character. Otherwise, returns false.
Parameters:
keyChar - a char, typically this is a keyboard key typed by the user

intervalAdded

public void intervalAdded(ListDataEvent e)
Invoked items have been added to the internal data model. The "interval" includes the first and last values added.
Specified by:
intervalAdded in interface ListDataListener
See Also:
ListDataListener

intervalRemoved

public void intervalRemoved(ListDataEvent e)
Invoked when values have been removed from the data model. The "interval" includes the first and last values removed.
Specified by:
intervalRemoved in interface ListDataListener
See Also:
ListDataListener

setEnabled

public void setEnabled(boolean b)
Enables the combo box so that items can be selected. When the combo box is disabled, items cannot be selected and values cannot be typed into its field (if it is editable).
Overrides:
setEnabled in class JComponent
Parameters:
b - a boolean value, where true enables the component and false disables it

configureEditor

public void configureEditor(ComboBoxEditor anEditor,
                            Object anItem)
Initializes the editor with the specified item.
Parameters:
anEditor - the ComboBoxEditor that displays the list item in the combo box field and allows it to be edited
anItem - the object to display and edit in the field

processKeyEvent

public void processKeyEvent(KeyEvent e)
Handles KeyEvents, looking for the Tab key. If the Tab key is found, the popup window is closed.
Overrides:
processKeyEvent in class JComponent
Parameters:
e - the KeyEvent containing the keyboard key that was pressed

isFocusTraversable

public boolean isFocusTraversable()
Returns true if the component can receive the focus. In this case, the component returns false if it is editable, so that the Editor object receives the focus, instead of the component.
Overrides:
isFocusTraversable in class JComponent
Returns:
true if the component can receive the focus, else false

setKeySelectionManager

public void setKeySelectionManager(JComboBox.KeySelectionManager aManager)
Sets the object that translates a keyboard character into a list selection. Typically, the first selection with a matching first character becomes the selected item.

getKeySelectionManager

public JComboBox.KeySelectionManager getKeySelectionManager()
Returns the list's key-selection manager.
Returns:
the KeySelectionManager currently in use

getItemCount

public int getItemCount()
Returns the number of items in the list.
Returns:
an integer equal to the number of items in the list

getItemAt

public Object getItemAt(int index)
Returns the list item at the specified index. If index is out of range (less than zero or greater than or equal to size) it will return null.
Parameters:
index - an integer indicating the list position, where the first item starts at zero
Returns:
the Object at that list position; or null if out of range

createDefaultKeySelectionManager

protected JComboBox.KeySelectionManager createDefaultKeySelectionManager()
Returns an instance of the default key-selection manager.
Returns:
the KeySelectionManager currently used by the list
See Also:
setKeySelectionManager(javax.swing.JComboBox.KeySelectionManager)

paramString

protected String paramString()
Returns a string representation of this JComboBox. 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 JComboBox

getAccessibleContext

public AccessibleContext getAccessibleContext()
Gets the AccessibleContext associated with this JComboBox. For combo boxes, the AccessibleContext takes the form of an AccessibleJComboBox. A new AccessibleJComboBox instance is created if necessary.
Specified by:
getAccessibleContext in interface Accessible
Overrides:
getAccessibleContext in class JComponent
Returns:
an AccessibleJComboBox that serves as the AccessibleContext of this JComboBox

JavaTM 2 Platform
Std. Ed. v1.3.1

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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