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:
-
ComboBoxModel
,DefaultComboBoxModel
, Serialized Form
Nested Class Summary
Modifier and Type | Class | Description |
---|---|---|
protected class | JComboBox.AccessibleJComboBox | This class implements accessibility support for the |
static interface | JComboBox.KeySelectionManager | The interface that defines a |
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(E[] items) | Creates a |
JComboBox(Vector<E> items) | Creates a |
JComboBox(ComboBoxModel<E> aModel) | Creates a |
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 |
void | addItem(E item) | Adds an item to the item list. |
void | addItemListener(ItemListener aListener) | Adds an |
void | addPopupMenuListener(PopupMenuListener l) | Adds a |
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 |
void | contentsChanged(ListDataEvent e) | This method is public as an implementation side effect. |
protected PropertyChangeListener | createActionPropertyChangeListener(Action a) | Creates and returns a |
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 |
void | firePopupMenuWillBecomeInvisible() | Notifies |
void | firePopupMenuWillBecomeVisible() | Notifies |
AccessibleContext | getAccessibleContext() | Gets the AccessibleContext associated with this JComboBox. |
Action | getAction() | Returns the currently 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 |
ComboBoxEditor | getEditor() | Returns the editor used to paint and edit the selected item in the |
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 |
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 |
PopupMenuListener[] | getPopupMenuListeners() | Returns an array of all the |
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 |
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 |
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 |
boolean | isLightWeightPopupEnabled() | Gets the value of the |
boolean | isPopupVisible() | Determines the visibility of the popup. |
protected String | paramString() | Returns a string representation of this |
void | processKeyEvent(KeyEvent e) | Handles |
void | removeActionListener(ActionListener l) | Removes an |
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 |
void | removeItemListener(ItemListener aListener) | Removes an |
void | removePopupMenuListener(PopupMenuListener l) | Removes a |
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 |
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 |
void | setEditor(ComboBoxEditor anEditor) | Sets the editor used to paint and edit the selected item in the |
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 |
void | setMaximumRowCount(int count) | Sets the maximum number of rows the |
void | setModel(ComboBoxModel<E> aModel) | Sets the data model that the |
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 |
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, 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, 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, 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
Field Detail
dataModel
protected ComboBoxModel<E> 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<E>)
renderer
protected ListCellRenderer<? super E> renderer
This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.
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.
lightWeightPopupEnabled
protected boolean lightWeightPopupEnabled
This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.
selectedItemReminder
protected Object selectedItemReminder
This protected field is implementation specific. Do not access directly or override.
Constructor Detail
JComboBox
public JComboBox(ComboBoxModel<E> 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
- theComboBoxModel
that provides the displayed list of items - See Also:
DefaultComboBoxModel
JComboBox
public JComboBox(E[] 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<E> 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()
Registers ancestor listener so that it will receive AncestorEvents
when it or any of its ancestors move or are made visible or invisible. Events are also sent when the component or its ancestors are added or removed from the containment hierarchy.
setUI
@BeanProperty(hidden=true, visualUpdate=true, description="The UI object that implements the Component\'s LookAndFeel.") public void setUI(ComboBoxUI ui)
Sets the L&F object that renders this component.
- Parameters:
-
ui
- theComboBoxUI
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 classJComponent
- See Also:
JComponent.updateUI()
getUIClassID
@BeanProperty(bound=false) public String getUIClassID()
Returns the name of the L&F class that renders this component.
- Overrides:
-
getUIClassID
in classJComponent
- 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.
- Overrides:
-
getUI
in classJComponent
- Returns:
- the ComboBoxUI object that renders this component
setModel
@BeanProperty(description="Model that the combo box uses to get data to display.") public void setModel(ComboBoxModel<E> aModel)
Sets the data model that the JComboBox
uses to obtain the list of items.
- Parameters:
-
aModel
- theComboBoxModel
that provides the displayed list of items
getModel
public ComboBoxModel<E> getModel()
Returns the data model currently used by the JComboBox
.
- Returns:
- the
ComboBoxModel
that provides the displayed list of items
setLightWeightPopupEnabled
@BeanProperty(expert=true, description="Set to <code>false</code> to require heavyweight popups.") public 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
. The decision of lightweight versus heavyweight is ultimately up to the JComboBox
. Lightweight windows are more efficient than heavyweight windows, but lightweight and heavyweight components do not mix well in a GUI. If your application mixes lightweight and heavyweight components, you should disable lightweight popups. The default value for the lightWeightPopupEnabled
property is true
, unless otherwise specified by the look and feel. Some look and feels always use heavyweight popups, no matter what the value of this property.
See the article Mixing Heavy and Light Components This method fires a property changed event.
- Parameters:
-
aFlag
- iftrue
, lightweight popups are desired
isLightWeightPopupEnabled
public boolean isLightWeightPopupEnabled()
Gets the value of the lightWeightPopupEnabled
property.
- Returns:
- the value of the
lightWeightPopupEnabled
property - See Also:
setLightWeightPopupEnabled(boolean)
setEditable
@BeanProperty(preferred=true, description="If true, the user can type a new value in the combo box.") 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
@BeanProperty(preferred=true, description="The maximum number of rows the popup should have") 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
@BeanProperty(expert=true, description="The renderer that paints the item selected in the list.") public 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. 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 or an icon. 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
- theListCellRenderer
that displays the selected item - See Also:
setEditor(javax.swing.ComboBoxEditor)
getRenderer
public ListCellRenderer<? super E> getRenderer()
Returns the renderer used to display the selected item in the JComboBox
field.
- Returns:
- the
ListCellRenderer
that displays the selected item.
setEditor
@BeanProperty(expert=true, description="The editor that combo box uses to edit the current value") 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
- theComboBoxEditor
that displays the selected item - See Also:
setRenderer(javax.swing.ListCellRenderer<? super E>)
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
@BeanProperty(bound=false, preferred=true, description="Sets the selected item in the JComboBox.") public void setSelectedItem(Object anObject)
Sets the selected item in the combo box display area to the object in the argument. If anObject
is in the list, the display area shows anObject
selected.
If anObject
is not in the list and the combo box is uneditable, it will not change the current selection. For editable combo boxes, the selection will change to anObject
.
If this constitutes a change in the selected item, ItemListener
s added to the combo box will be notified with one or two ItemEvent
s. If there is a current selected item, an ItemEvent
will be fired and the state change will be ItemEvent.DESELECTED
. If anObject
is in the list and is not currently selected then an ItemEvent
will be fired and the state change will be ItemEvent.SELECTED
.
ActionListener
s added to the combo box will be notified with an ActionEvent
when this method is called.
- Parameters:
-
anObject
- the list object to select; usenull
to clear the selection
getSelectedItem
public Object getSelectedItem()
Returns the current selected item.
If the combo box is editable, then this value may not have been added to the combo box with addItem
, insertItemAt
or the data constructors.
- Returns:
- the current selected Object
- See Also:
setSelectedItem(java.lang.Object)
setSelectedIndex
@BeanProperty(bound=false, preferred=true, description="The item at index is selected.") 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 and -1 indicates no selection - Throws:
-
IllegalArgumentException
- ifanIndex
< -1 oranIndex
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
getPrototypeDisplayValue
public E getPrototypeDisplayValue()
Returns the "prototypical display" value - an Object used for the calculation of the display height and width.
- Returns:
- the value of the
prototypeDisplayValue
property - Since:
- 1.4
- See Also:
setPrototypeDisplayValue(E)
setPrototypeDisplayValue
@BeanProperty(visualUpdate=true, description="The display prototype value, used to compute display width and height.") public void setPrototypeDisplayValue(E prototypeDisplayValue)
Sets the prototype display value used to calculate the size of the display for the UI portion.
If a prototype display value is specified, the preferred size of the combo box is calculated by configuring the renderer with the prototype display value and obtaining its preferred size. Specifying the preferred display value is often useful when the combo box will be displaying large amounts of data. If no prototype display value has been specified, the renderer must be configured for each value from the model and its preferred size obtained, which can be relatively expensive.
- Parameters:
-
prototypeDisplayValue
- the prototype display value - Since:
- 1.4
- See Also:
getPrototypeDisplayValue()
addItem
public void addItem(E item)
Adds an item to the item list. This method works only if the JComboBox
uses a mutable data model.
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:
-
item
- the item to add to the list - See Also:
MutableComboBoxModel
insertItemAt
public void insertItemAt(E item, int index)
Inserts an item into the item list at a given index. This method works only if the JComboBox
uses a mutable data model.
- Parameters:
-
item
- the item to add to the list -
index
- an integer specifying the position at which to add the item - See Also:
MutableComboBoxModel
removeItem
public void removeItem(Object anObject)
Removes an item from the item list. This method works only if the JComboBox
uses a mutable data model.
- Parameters:
-
anObject
- the object to remove from the item list - See Also:
MutableComboBoxModel
removeItemAt
public void removeItemAt(int anIndex)
Removes the item at anIndex
This method works only if the JComboBox
uses a mutable data model.
- Parameters:
-
anIndex
- an int specifying the index of the item to remove, where 0 indicates the first item in the list - See Also:
MutableComboBoxModel
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.
- Parameters:
-
v
- iftrue
shows the popup, otherwise, hides the popup.
isPopupVisible
public boolean isPopupVisible()
Determines the visibility of the popup.
- Returns:
- true if the popup is visible, otherwise returns false
addItemListener
public void addItemListener(ItemListener aListener)
Adds an ItemListener
.
aListener
will receive one or two ItemEvent
s when the selected item changes.
- Specified by:
-
addItemListener
in interfaceItemSelectable
- Parameters:
-
aListener
- theItemListener
that is to be notified - See Also:
setSelectedItem(java.lang.Object)
removeItemListener
public void removeItemListener(ItemListener aListener)
Removes an ItemListener
.
- Specified by:
-
removeItemListener
in interfaceItemSelectable
- Parameters:
-
aListener
- theItemListener
to remove - See Also:
ItemEvent
getItemListeners
@BeanProperty(bound=false) public ItemListener[] getItemListeners()
Returns an array of all the ItemListener
s added to this JComboBox with addItemListener().
- Returns:
- all of the
ItemListener
s added or an empty array if no listeners have been added - Since:
- 1.4
addActionListener
public void addActionListener(ActionListener l)
Adds an ActionListener
.
The ActionListener
will receive an ActionEvent
when a selection has been made. If the combo box is editable, then an ActionEvent
will be fired when editing has stopped.
- Parameters:
-
l
- theActionListener
that is to be notified - See Also:
setSelectedItem(java.lang.Object)
removeActionListener
public void removeActionListener(ActionListener l)
Removes an ActionListener
.
- Parameters:
-
l
- theActionListener
to remove
getActionListeners
@BeanProperty(bound=false) public ActionListener[] getActionListeners()
Returns an array of all the ActionListener
s added to this JComboBox with addActionListener().
- Returns:
- all of the
ActionListener
s added or an empty array if no listeners have been added - Since:
- 1.4
addPopupMenuListener
public void addPopupMenuListener(PopupMenuListener l)
Adds a PopupMenu
listener which will listen to notification messages from the popup portion of the combo box.
For all standard look and feels shipped with Java, the popup list portion of combo box is implemented as a JPopupMenu
. A custom look and feel may not implement it this way and will therefore not receive the notification.
- Parameters:
-
l
- thePopupMenuListener
to add - Since:
- 1.4
removePopupMenuListener
public void removePopupMenuListener(PopupMenuListener l)
Removes a PopupMenuListener
.
- Parameters:
-
l
- thePopupMenuListener
to remove - Since:
- 1.4
- See Also:
addPopupMenuListener(javax.swing.event.PopupMenuListener)
getPopupMenuListeners
@BeanProperty(bound=false) public PopupMenuListener[] getPopupMenuListeners()
Returns an array of all the PopupMenuListener
s added to this JComboBox with addPopupMenuListener().
- Returns:
- all of the
PopupMenuListener
s added or an empty array if no listeners have been added - Since:
- 1.4
firePopupMenuWillBecomeVisible
public void firePopupMenuWillBecomeVisible()
Notifies PopupMenuListener
s that the popup portion of the combo box will become visible.
This method is public but should not be called by anything other than the UI delegate.
- Since:
- 1.4
- See Also:
addPopupMenuListener(javax.swing.event.PopupMenuListener)
firePopupMenuWillBecomeInvisible
public void firePopupMenuWillBecomeInvisible()
Notifies PopupMenuListener
s that the popup portion of the combo box has become invisible.
This method is public but should not be called by anything other than the UI delegate.
- Since:
- 1.4
- See Also:
addPopupMenuListener(javax.swing.event.PopupMenuListener)
firePopupMenuCanceled
public void firePopupMenuCanceled()
Notifies PopupMenuListener
s that the popup portion of the combo box has been canceled.
This method is public but should not be called by anything other than the UI delegate.
- Since:
- 1.4
- See Also:
addPopupMenuListener(javax.swing.event.PopupMenuListener)
setActionCommand
public void setActionCommand(String aCommand)
Sets the action command 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
@BeanProperty(visualUpdate=true, description="the Action instance connected with this ActionEvent source") 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
independently added with addActionListener
. If the Action
is already a registered ActionListener
for the ActionEvent
source, it is not re-registered.
Setting the Action
results in immediately changing all the properties described in Swing Components Supporting Action
. Subsequently, the combobox's properties are automatically updated as the Action
's properties change.
This method uses three other methods to set and help track the Action
's property values. It uses the configurePropertiesFromAction
method to immediately change the combobox's properties. To track changes in the Action
's property values, this method registers the PropertyChangeListener
returned by createActionPropertyChangeListener
. The default PropertyChangeListener
invokes the actionPropertyChanged
method when a property in the Action
changes.
- Parameters:
-
a
- theAction
for theJComboBox
, ornull
. - Since:
- 1.3
- See Also:
-
Action
,getAction()
,configurePropertiesFromAction(javax.swing.Action)
,createActionPropertyChangeListener(javax.swing.Action)
,actionPropertyChanged(javax.swing.Action, java.lang.String)
getAction
public Action getAction()
Returns the currently set Action
for this ActionEvent
source, or null
if no Action
is set.
- Returns:
- the
Action
for thisActionEvent
source; ornull
- Since:
- 1.3
- See Also:
-
Action
,setAction(javax.swing.Action)
configurePropertiesFromAction
protected void configurePropertiesFromAction(Action a)
Sets the properties on this combobox to match those in the specified Action
. Refer to Swing Components Supporting Action
for more details as to which properties this sets.
- Parameters:
-
a
- theAction
from which to get the properties, ornull
- Since:
- 1.3
- See Also:
-
Action
,setAction(javax.swing.Action)
createActionPropertyChangeListener
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.
Warning: If you subclass this do not create an anonymous inner class. If you do the lifetime of the combobox will be tied to that of the Action
.
- Parameters:
-
a
- the combobox's action - Returns:
- the
PropertyChangeListener
- Since:
- 1.3
- See Also:
-
Action
,setAction(javax.swing.Action)
actionPropertyChanged
protected void actionPropertyChanged(Action action, String propertyName)
Updates the combobox's state in response to property changes in 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.
- Parameters:
-
action
- theAction
associated with this combobox -
propertyName
- the name of the property that changed - Since:
- 1.6
- See Also:
-
Action
,configurePropertiesFromAction(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.
- See Also:
EventListenerList
selectedItemChanged
protected void selectedItemChanged()
This protected method is implementation specific. Do not access directly or override.
getSelectedObjects
@BeanProperty(bound=false) public Object[] getSelectedObjects()
Returns an array containing the selected item. This method is implemented for compatibility with ItemSelectable
.
- Specified by:
-
getSelectedObjects
in interfaceItemSelectable
- Returns:
- an array of
Objects
containing one element -- the selected item
actionPerformed
public void actionPerformed(ActionEvent e)
This method is public as an implementation side effect. do not call or override.
- Specified by:
-
actionPerformed
in interfaceActionListener
- Parameters:
-
e
- the event to be processed
contentsChanged
public void contentsChanged(ListDataEvent e)
This method is public as an implementation side effect. do not call or override.
- Specified by:
-
contentsChanged
in interfaceListDataListener
- Parameters:
-
e
- aListDataEvent
encapsulating the event information
intervalAdded
public void intervalAdded(ListDataEvent e)
This method is public as an implementation side effect. do not call or override.
- Specified by:
-
intervalAdded
in interfaceListDataListener
- Parameters:
-
e
- aListDataEvent
encapsulating the event information
intervalRemoved
public void intervalRemoved(ListDataEvent e)
This method is public as an implementation side effect. do not call or override.
- Specified by:
-
intervalRemoved
in interfaceListDataListener
- Parameters:
-
e
- aListDataEvent
encapsulating the event information
selectWithKeyChar
public 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. Otherwise, returns false.
- Parameters:
-
keyChar
- a char, typically this is a keyboard key typed by the user - Returns:
-
true
if there is an item corresponding to that character. Otherwise, returnsfalse
.
setEnabled
@BeanProperty(preferred=true, description="The enabled state of the component.") 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 classJComponent
- Parameters:
-
b
- a boolean value, where true enables the component and false disables it - See Also:
-
Component.isEnabled()
,Component.isLightweight()
configureEditor
public void configureEditor(ComboBoxEditor anEditor, Object anItem)
Initializes the editor with the specified item.
- Parameters:
-
anEditor
- theComboBoxEditor
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 KeyEvent
s, looking for the Tab key. If the Tab key is found, the popup window is closed.
- Overrides:
-
processKeyEvent
in classJComponent
- Parameters:
-
e
- theKeyEvent
containing the keyboard key that was pressed - See Also:
-
KeyEvent
,KeyListener
,KeyboardFocusManager
,DefaultKeyboardFocusManager
,Component.processEvent(java.awt.AWTEvent)
,Component.dispatchEvent(java.awt.AWTEvent)
,Component.addKeyListener(java.awt.event.KeyListener)
,Component.enableEvents(long)
,Component.isShowing()
setKeySelectionManager
@BeanProperty(bound=false, expert=true, description="The objects that changes the selection when a key is pressed.") 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.
- Parameters:
-
aManager
- a key selection manager
getKeySelectionManager
public JComboBox.KeySelectionManager getKeySelectionManager()
Returns the list's key-selection manager.
- Returns:
- the
KeySelectionManager
currently in use
getItemCount
@BeanProperty(bound=false) 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 E 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 item 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 classJComponent
- Returns:
- a string representation of this
JComboBox
getAccessibleContext
@BeanProperty(bound=false) 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 interfaceAccessible
- Overrides:
-
getAccessibleContext
in classComponent
- Returns:
- an AccessibleJComboBox that serves as the AccessibleContext of this JComboBox