javax.swing
Class JComboBox

java.lang.Object
  java.awt.Component
      java.awt.Container
          javax.swing.JComponent
              javax.swing.JComboBox

All Implemented Interfaces:

ActionListener, ImageObserver, ItemSelectable, MenuContainer, Serializable, EventListener, Accessible, ListDataListener

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

A component that combines a button or editable 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 an editable field into which the user can type a value.

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^TM has been added to the java.beans package. Please see XMLEncoder.

See How to Use Combo Boxes in The Java Tutorial for further information.

See Also:

ComboBoxModel, DefaultComboBoxModel

Nested 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.

 

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

 

Field Summary
protected  String	actionCommand           This protected field is implementation specific.
protected  ComboBoxModel	dataModel           This protected field is implementation specific.
protected  ComboBoxEditor	editor           This protected field is implementation specific.
protected  boolean	isEditable           This protected field is implementation specific.
protected  JComboBox.KeySelectionManager	keySelectionManager           This protected field is implementation specific.
protected  boolean	lightWeightPopupEnabled           This protected field is implementation specific.
protected  int	maximumRowCount           This protected field is implementation specific.
protected  ListCellRenderer	renderer           This protected field is implementation specific.
protected  Object	selectedItemReminder           This protected field is implementation specific.

 

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 its 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.
protected  void	actionPropertyChanged(Action action, String propertyName)           Updates the combobox's state in response to property changes in associated action.
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	addPopupMenuListener(PopupMenuListener l)           Adds a PopupMenu listener which will listen to notification messages from the popup portion of the combo box.
void	configureEditor(ComboBoxEditor anEditor, Object anItem)           Initializes the editor with the specified item.
protected  void	configurePropertiesFromAction(Action a)           Sets the properties on this combobox to match those in the specified Action.
void	contentsChanged(ListDataEvent e)           This method is public as an implementation side effect.
protected  PropertyChangeListener	createActionPropertyChangeListener(Action a)           Creates and returns a PropertyChangeListener that is responsible for listening for changes from the specified Action and updating the appropriate properties.
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.
void	firePopupMenuCanceled()           Notifies PopupMenuListeners that the popup portion of the combo box has been canceled.
void	firePopupMenuWillBecomeInvisible()           Notifies PopupMenuListeners that the popup portion of the combo box has become invisible.
void	firePopupMenuWillBecomeVisible()           Notifies PopupMenuListeners that the popup portion of the combo box will become visible.
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.
ActionListener[]	getActionListeners()           Returns an array of all the ActionListeners added to this JComboBox with addActionListener().
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.
ItemListener[]	getItemListeners()           Returns an array of all the ItemListeners added to this JComboBox with addItemListener().
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.
PopupMenuListener[]	getPopupMenuListeners()           Returns an array of all the PopupMenuListeners added to this JComboBox with addPopupMenuListener().
Object	getPrototypeDisplayValue()           Returns the "prototypical display" value - an Object used for the calculation of the display height and width.
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 current 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)           This method is public as an implementation side effect.
void	intervalRemoved(ListDataEvent e)           This method is public as an implementation side effect.
boolean	isEditable()           Returns true if the JComboBox is editable.
boolean	isLightWeightPopupEnabled()           Gets the value of the lightWeightPopupEnabled property.
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 a mutable data model.
void	removeItemListener(ItemListener aListener)           Removes an ItemListener.
void	removePopupMenuListener(PopupMenuListener l)           Removes a PopupMenuListener.
protected  void	selectedItemChanged()           This protected method is implementation specific.
boolean	selectWithKeyChar(char keyChar)           Selects the list item that corresponds 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 command 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)           Sets the lightWeightPopupEnabled property, which provides a hint as to whether or not a lightweight Component should be used to contain the JComboBox, versus a heavyweight Component such as a Panel or a Window.
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	setPrototypeDisplayValue(Object prototypeDisplayValue)           Sets the prototype display value used to calculate the size of the display for the UI portion.
void	setRenderer(ListCellRenderer aRenderer)           Sets the renderer that paints the list items and 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 combo box display area to the object in the argument.
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()           Resets the UI property to a value from the current look and feel.

 

Methods inherited from class javax.swing.JComponent

addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingForPrint, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintBorder, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processMouseEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, update

 

Methods inherited from class java.awt.Container

add, add, add, add, add, addContainerListener, addImpl, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, getMousePosition, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setLayout, transferFocusBackward, transferFocusDownCycle, validate, validateTree

 

Methods inherited from class java.awt.Component

action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, createVolatileImage, createVolatileImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusUpCycle

 

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

 

Field Detail

dataModel

protected ComboBoxModel dataModel

This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.

See Also:

getModel(), setModel(javax.swing.ComboBoxModel)

renderer

protected ListCellRenderer renderer

This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.

See Also:

getRenderer(), setRenderer(javax.swing.ListCellRenderer)

editor

protected ComboBoxEditor editor

This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.

See Also:

getEditor(), setEditor(javax.swing.ComboBoxEditor)

maximumRowCount

protected int maximumRowCount

This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.

See Also:

getMaximumRowCount(), setMaximumRowCount(int)

isEditable

protected boolean isEditable

This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.

See Also:

isEditable, setEditable(boolean)

keySelectionManager

protected JComboBox.KeySelectionManager keySelectionManager

This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.

See Also:

setKeySelectionManager(javax.swing.JComboBox.KeySelectionManager), getKeySelectionManager()

actionCommand

protected String actionCommand

This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.

See Also:

setActionCommand(java.lang.String), getActionCommand()

lightWeightPopupEnabled

protected boolean lightWeightPopupEnabled

This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.

See Also:

setLightWeightPopupEnabled(boolean), isLightWeightPopupEnabled()

selectedItemReminder

protected Object selectedItemReminder

This protected field is implementation specific. Do not access directly or override.

JComboBox

public JComboBox(ComboBoxModel aModel)

Creates a JComboBox that takes its 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

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()

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

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