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Class com.sun.java.swing.JComboBox

java.lang.Object
   |
   +----java.awt.Component
           |
           +----java.awt.Container
                   |
                   +----com.sun.java.swing.JComponent
                           |
                           +----com.sun.java.swing.JComboBox

public class JComboBox

extends JComponent

implements ItemSelectable, ListDataListener, ActionListener, Accessible

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 Swing1.0 applications. It will not be possible to load serialized Swing1.0 objects with future releases of Swing. The JDK1.2 release of Swing will be the compatibility baseline for the serialized form of Swing objects.

actionCommand

dataModel

editor

isEditable

keySelectionManager

lightWeightPopupEnabled

maximumRowCount

renderer

selectedItemReminder

JComboBox()

Creates a JComboBox with a default data model.

JComboBox(ComboBoxModel)

Creates a JComboBox that takes its items from an existing ComboBoxDataModel.

JComboBox(Object[])

Creates a JComboBox that contains the elements in the specified array.

JComboBox(Vector)

Creates a JComboBox that contains the elements in the specified Vector.

actionPerformed(ActionEvent)

This method is public as an implementation side effect.

addActionListener(ActionListener)

Adds an ActionListener.

addItem(Object)

Adds an item to the item list.

addItemListener(ItemListener)

Adds an ItemListener.

configureEditor(ComboBoxEditor, Object)

Initializes the editor with the specified item.

contentsChanged(ListDataEvent)

This method is public as an implementation side effect.

createDefaultKeySelectionManager()

Returns an instance of the default key-selection manager.

fireActionEvent()

Notify all listeners that have registered interest for notification on this event type.

fireItemStateChanged(ItemEvent)

Notify all listeners that have registered interest for notification on this event type.

getAccessibleContext()

Get the AccessibleContext associated with this JComponent

getActionCommand()

Returns the action commnand that is included in the event sent to action listeners.

getEditor()

Returns the editor used to paint and edit the selected item in the JComboBox field.

getItemAt(int)

Returns the list item at the specified index.

getItemCount()

Returns the number of items in the list.

getKeySelectionManager()

Returns the list's key-selection manager.

getMaximumRowCount()

Returns the maximum number of items the combo box can display without a scrollbar

getModel()

Returns the data model currently used by the JComboBox.

getRenderer()

Returns the renderer used to display the selected item in the JComboBox field.

getSelectedIndex()

Returns the index of the currently selected item in the list.

getSelectedItem()

Returns the currently selected item.

getSelectedObjects()

Returns an array containing the selected item.

getUI()

Returns the L&F object that renders this component.

getUIClassID()

Returns the name of the L&F class that renders this component.

hidePopup()

Causes the combo box to close its popup window

insertItemAt(Object, int)

Inserts an item into the item list at a given index.

installAncestorListener()

intervalAdded(ListDataEvent)

Invoked items have been added to the internal data model.

intervalRemoved(ListDataEvent)

Invoked when values have been removed from the data model.

isEditable()

Returns true if the JComboBox is editable.

isFocusTraversable()

Returns true if the component can receive the focus.

isLightWeightPopupEnabled()

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

isOpaque()

Returns true to indicate that this component paints every pixel in its range.

processKeyEvent(KeyEvent)

Handles KeyEvents, looking for the Tab key.

removeActionListener(ActionListener)

Removes an ActionListener

removeAllItems()

Removes all items from the item list.

removeItem(Object)

Removes an item from the item list.

removeItemAt(int)

Removes the item at anIndex This method works only if the JComboBox uses the default data model.

removeItemListener(ItemListener)

Removes an ItemListener

selectedItemChanged()

This method is called when the selected item changes.

selectWithKeyChar(char)

Selects the list item that correponds to the specified keyboard character and returns true, if there is an item corresponding to that character.

setActionCommand(String)

Sets the action commnand that should be included in the event sent to action listeners.

setEditable(boolean)

Determines whether the JComboBox field is editable.

setEditor(ComboBoxEditor)

Sets the editor used to paint and edit the selected item in the JComboBox field.

setEnabled(boolean)

Enables the combo box so that items can be selected.

setKeySelectionManager(JComboBox. KeySelectionManager)

Sets the object that translates a keyboard character into a list selection.

setLightWeightPopupEnabled(boolean)

When displaying the popup, JComboBox choose to use a light weight popup if it fits.

setMaximumRowCount(int)

Sets the maximum number of rows the JComboBox displays.

setModel(ComboBoxModel)

Sets the data model that the JComboBox uses to obtain the list of items.

setRenderer(ListCellRenderer)

Sets the renderer that paints the item selected from the list in the JComboBox field.

setSelectedIndex(int)

Selects the item at index anIndex.

setSelectedItem(Object)

Sets the selected item in the JComboBox by specifying the object in the list.

setUI(ComboBoxUI)

Sets the L&F object that renders this component.

showPopup()

Causes the combo box to display its popup window

updateUI()

Notification from the UIFactory that the L&F has changed.

 protected ComboBoxModel dataModel

 protected ListCellRenderer renderer

 protected ComboBoxEditor editor

 protected int maximumRowCount

 protected boolean isEditable

 protected Object selectedItemReminder

 protected JComboBox. KeySelectionManager keySelectionManager

 protected String actionCommand

 protected boolean lightWeightPopupEnabled

 public JComboBox(ComboBoxModel aModel)

Creates a JComboBox that takes its items from an existing ComboBoxDataModel.

Parameters:

aModel - the ComboBoxModel that provides the displayed list of items

 public JComboBox(Object items[])

Creates a JComboBox that contains the elements in the specified array.

 public JComboBox(Vector items)

Creates a JComboBox that contains the elements in the specified Vector.

 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.

 protected void installAncestorListener()

 public void setUI(ComboBoxUI ui)

Sets the L&F object that renders this component.

Parameters:

ui - the ComboBoxUI L&F object

See Also:

getUI

 public void updateUI()

Notification from the UIFactory that the L&F has changed.

Overrides:

updateUI in class JComponent

See Also:

updateUI

 public String getUIClassID()

Returns the name of the L&F class that renders this component.

Returns:

"ComboBoxUI"

Overrides:

getUIClassID in class JComponent

See Also:

getUIClassID, getUI

 public ComboBoxUI getUI()

Returns the L&F object that renders this component.

Returns:

the ComboBoxUI object that renders this component

 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

 public ComboBoxModel getModel()

Returns the data model currently used by the JComboBox.

Returns:

the ComboBoxModel that provides the displayed list of items

 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.

 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

 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 inthe field, but the selection cannot be modified.

Parameters:

aFlag - a boolean value, where true indicates that the field is editable

 public boolean isEditable()

Returns true if the JComboBox is editable.

Returns:

true if the JComboBox is editable, else false

 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 int specifying the maximum number of items to display in the list before using a scrollbar

 public int getMaximumRowCount()

Returns the maximum number of items the combo box can display without a scrollbar

Returns:

an int specifying the maximum number of items that are displayed in the list before using a scrollbar

 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

 public ListCellRenderer getRenderer()

Returns the renderer used to display the selected item in the JComboBox field.

Returns:

the ListCellRenderer that displays the selected item.

 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

 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

 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. If the object does not exist in the list, the default data model selects the first item in the list.

Parameters:

anObject - the list object to select

 public Object getSelectedItem()

Returns the currently selected item.

Returns:

the currently selected list object from the data model

 public void setSelectedIndex(int anIndex)

Selects the item at index anIndex.

Parameters:

anIndex - an int specifying the list item to select, where 0 specifies the first item in the list

 public int getSelectedIndex()

Returns the index of the currently selected item in the list. The result is not always defined if the JComboBox box allows selected items that are not in the list. Returns -1 if the receiving JComboBox has no selected item or if the selected item is not in the list of items.

Returns:

an int 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

 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.

Parameters:

anObject - the Object to add to the list

 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 int specifying the position at which to add the item

 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

 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

 public void removeAllItems()

Removes all items 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.

 public void showPopup()

Causes the combo box to display its popup window

 public void hidePopup()

Causes the combo box to close its popup window

 public void addItemListener(ItemListener aListener)

Adds an ItemListener. aListener will receive an event when the selected item changes.

Parameters:

aListener - the ItemListener that is to be notified

 public void removeItemListener(ItemListener aListener)

Removes an ItemListener

Parameters:

aListener - the ItemListener to remove

 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

 public void removeActionListener(ActionListener l)

Removes an ActionListener

Parameters:

l - the ActionListener to remove

 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.

 public String getActionCommand()

Returns the action commnand that is included in the event sent to action listeners.

Returns:

the string containing the "command" that is sent to action listeners.

 protected void fireItemStateChanged(ItemEvent e)

Notify all listeners that have registered interest for notification on this event type.

See Also:

EventListenerList

 protected void fireActionEvent()

Notify all listeners that have registered interest for notification on this event type.

See Also:

EventListenerList

 protected void selectedItemChanged()

This method is called when the selected item changes. Its default implementation notifies the item listeners

 public Object[] getSelectedObjects()

Returns an array containing the selected item. This method is implemented for compatibility with ItemSelectable.

Returns:

s an array of Objects containing one element -- the selected item

 public void actionPerformed(ActionEvent e)

This method is public as an implementation side effect. do not call or override.

 public void contentsChanged(ListDataEvent e)

This method is public as an implementation side effect. do not call or override.

See Also:

ListDataListener

 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

 public void intervalAdded(ListDataEvent e)

Invoked items have been added to the internal data model. The "interval" includes the first and last values added.

See Also:

ListDataListener

 public void intervalRemoved(ListDataEvent e)

Invoked when values have been removed from the data model. The"interval" includes the first and last values removed.

See Also:

ListDataListener

 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).

Parameters:

b - a boolean value, where true enables the component and false disables it

Overrides:

setEnabled in class Component

 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

 public void processKeyEvent(KeyEvent e)

Handles KeyEvents, looking for the Tab key. If the Tab key is found, the popup window is closed.

Parameters:

e - the KeyEvent containing the keyboard key that was pressed

Overrides:

processKeyEvent in class JComponent

 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.

Returns:

true if the component can receive the focus, else false.

Overrides:

isFocusTraversable in class JComponent

 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.

 public JComboBox. KeySelectionManager getKeySelectionManager()

Returns the list's key-selection manager.

Returns:

the KeySelectionManager currently in use

 public int getItemCount()

Returns the number of items in the list.

Returns:

an int equal to the number of items in the list

 public Object getItemAt(int index)

Returns the list item at the specified index.

Parameters:

index - an int indicating the list position, where the first item starts at zero

Returns:

the Object at that list position

 protected JComboBox. KeySelectionManager createDefaultKeySelectionManager()

Returns an instance of the default key-selection manager.

Returns:

the KeySelectionManager currently used by the list

See Also:

setKeySelectionManager

 public boolean isOpaque()

Returns true to indicate that this component paints every pixel in its range. (In other words, it does not have a transparent background or foreground.)

Overrides:

isOpaque in class JComponent

See Also:

isOpaque

 public AccessibleContext getAccessibleContext()

Get the AccessibleContext associated with this JComponent

Returns:

the AccessibleContext of this JComponent

Overrides:

getAccessibleContext in class JComponent

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