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/OpenJDK 21

Class JComboBox<E>

java.lang.Object

java.awt.Component

java.awt.Container

javax.swing.JComponent

javax.swing.JComboBox<E>

Type Parameters:: E - the type of the elements of this combo box

All Implemented Interfaces:: ActionListener, ImageObserver, ItemSelectable, MenuContainer, Serializable, EventListener, Accessible, ListDataListener

@JavaBean(defaultProperty="UI", description="A combination of a text field and a drop-down list.") public class JComboBox<E> 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 has been added to the java.beans package. Please see XMLEncoder.

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

Since:

1.2

See Also:

Nested Class Summary

Modifier and Type	Class	Description
`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 declared in class javax.swing.JComponent

JComponent.AccessibleJComponent

Nested classes/interfaces declared in class java.awt.Container

Container.AccessibleAWTContainer

Nested classes/interfaces declared in class java.awt.Component

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

Field Summary

Modifier and Type	Field	Description
`protected String`	`actionCommand`	This protected field is implementation specific.
`protected ComboBoxModel<E>`	`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<? super E>`	`renderer`	This protected field is implementation specific.
`protected Object`	`selectedItemReminder`	This protected field is implementation specific.

Fields declared in class javax.swing.JComponent

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

Fields declared in class java.awt.Component

accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields declared in interface java.awt.image.ImageObserver

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

Constructor Summary

Constructor	Description
`JComboBox()`	Creates a `JComboBox` with a default data model.
`JComboBox(E[] items)`	Creates a `JComboBox` that contains the elements in the specified array.
`JComboBox(Vector<E> items)`	Creates a `JComboBox` that contains the elements in the specified Vector.
`JComboBox(ComboBoxModel<E> aModel)`	Creates a `JComboBox` that takes its items from an existing `ComboBoxModel`.

Method Summary

Modifier and Type	Method	Description
`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(E item)`	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 `PopupMenuListener`s that the popup portion of the combo box has been canceled.
`void`	`firePopupMenuWillBecomeInvisible()`	Notifies `PopupMenuListener`s that the popup portion of the combo box has become invisible.
`void`	`firePopupMenuWillBecomeVisible()`	Notifies `PopupMenuListener`s 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 `ActionListener`s added to this JComboBox with addActionListener().
`ComboBoxEditor`	`getEditor()`	Returns the editor used to paint and edit the selected item in the `JComboBox` field.
`E`	`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 `ItemListener`s 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<E>`	`getModel()`	Returns the data model currently used by the `JComboBox`.
`PopupMenuListener[]`	`getPopupMenuListeners()`	Returns an array of all the `PopupMenuListener`s added to this JComboBox with addPopupMenuListener().
`E`	`getPrototypeDisplayValue()`	Returns the "prototypical display" value - an Object used for the calculation of the display height and width.
`ListCellRenderer<? super E>`	`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(E item, int index)`	Inserts an item into the item list at a given index.
`protected void`	`installAncestorListener()`	Registers ancestor listener so that it will receive `AncestorEvents` when it or any of its ancestors move or are made visible or invisible.
`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 `KeyEvent`s, 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<E> 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(E prototypeDisplayValue)`	Sets the prototype display value used to calculate the size of the display for the UI portion.
`void`	`setRenderer(ListCellRenderer<? super E> 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 declared in class javax.swing.JComponent

addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, 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, hide, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingForPrint, isPaintingOrigin, 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 declared in 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, transferFocusDownCycle, validate, validateTree

Methods declared in 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, 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, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, 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, requestFocus, requestFocus, requestFocusInWindow, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setMixingCutoutShape, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait