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Class jclass.bwt.JCComboBox

java.lang.Object
   |
   +----java.awt.Component
           |
           +----java.awt.Container
                   |
                   +----java.awt.Panel
                           |
                           +----jclass.bwt.JCContainer
                                   |
                                   +----jclass.bwt.JCComboBox

public class JCComboBox

extends JCContainer

implements KeyListener, JCListListener, JCActionListener, JCItemSelectable

Note that on MS-Windows, AWT currently uses a Windows ComboBox as the peer for its Choice component. JCComboBox provides this functionality on all platforms.

The list may be displayed at all times, or may only drop down when the user presses an arrow button next to the TextField (a "drop-down" ComboBox).

Behavior
If the arrow button is pressed and released, the list pops up and stays up until the user clicks an item inside it, hits RETURN, clicks outside the list, or presses ESCAPE. If an item is clicked or RETURN is hit, the item is copied to the text field.

Properties

Name	Method
Background	setBackground
Font	setFont
Foreground	setForeground
Items	setItems
Insets	setInsets
PreferredSize	setPreferredSize
Style	setStyle
Text	setText
UserData	setUserData
VisibleRows	setVisibleRows

Events

Class	Listener	Description
JCActionEvent	addActionListener	Called when the ENTER key is hit
JCItemEvent	addItemListener	Cafter the user selects an item
JCComboBoxEvent	addComboBoxListener	Called before the list is displayed, and after the user has made a selection

actionListeners

List of JCActionEvent listeners

BEGIN

COMBOBOX_DROPDOWN

COMBOBOX_DROPDOWN_LIST

COMBOBOX_SIMPLE

END

itemListeners

List of JCItemEvent listeners

listeners

List of JCComboBoxEvent listeners

JCComboBox()

Creates an empty ComboBox.

JCComboBox(JCVector)

Creates an empty ComboBox with the specified list items.

JCComboBox(JCVector, Applet, String)

Creates a comboBox which reads parameters from the applet's HTML file.

JCComboBox(String[], String)

Creates a comboBox with the specified items and name.

actionPerformed(JCActionEvent)

If the arrow button was clicked, calls showListAction to display the list.
If the list is displayed and the RETURN key was hit, calls setTextAction to copy the selected item to the text field.

add(String)

Adds an item to the list.

addActionListener(JCActionListener)

Adds the specified action listener to receive JCTextField action events.

addComboBoxListener(JCComboBoxListener)

Adds the specified JCComboBoxEvent listener to receive events.

addItemListener(JCItemListener)

Adds the specified item listener to receive item selection events.

addNotify()

Creates the Panel's peer.

getButton()

Gets the button component.

getItem(int)

Returns the item at the specified index in the list.

getItemCount()

Returns the number of items in the list.

getItems()

Gets the list's values as a list of Strings.

getList()

Gets the list component.

getParameters()

Reads the parameter values from the HTML page using the component's applet.

getSelectedIndex()

Returns the index of the currently selected item.

getSelectedIndexes()

Returns an array (length 1) containing the currently selected item.

getSelectedItem()

Returns a String representation of the current choice.

getSelectedObjects()

Returns an array (length 1) containing the currently selected item.

getStyle()

Gets the Style value.

getText()

Gets the value of the text.

getTextField()

Gets the component to be used as the data entry field.

itemStateChanged(JCItemEvent)

JCItemListener method - no-op

keyPressed(KeyEvent)

keyReleased(KeyEvent)

keyTyped(KeyEvent)

layout()

listItemSelectBegin(JCListEvent)

JCListListener method - no-op

listItemSelectEnd(JCListEvent)

If the user clicked an item, calls setTextAction to copy the item to the text field.

paintInterior(Graphics)

Draws the shadows and title.

postComboBoxEvent(int, Object)

Posts a JCComboBoxEvent

preferredHeight()

Gets the subclass' preferred height (default: 100).

preferredWidth()

Gets the subclass' preferred width (default: 100).

remove(String)

Removes the first occurrence of an item from the list.

removeActionListener(JCActionListener)

Removes the specified action listener so it no longer receives action events.

removeAll()

Removes all items from the list.

removeComboBoxListener(JCComboBoxListener)

Removes the specified listener so it no longer receives JCComboBoxEvents.

removeItemListener(JCItemListener)

Removes the specified item listener so it no longer receives item events.

select(int)

Selects the item with the specified postion.

select(Object)

Selects the specified item.

setItems(String[])

Sets the list's values as a list of Strings.

setLayout(LayoutManager)

Sets the layout manager for this container.

setStyle(int)

Sets the style, which specifies whether the list is always displayed and whether the text field is editable.

setText(String)

Sets the text field's value to the specified string.

HTML param name/value: "Text"/string

setTextAction(String)

Copies the item to the text field, after first posting a JCComboBoxEvent to allow the application to disallow the selection or change its value.

setVisibleRows(int)

Sets the number of visible rows; if set to 0 (default), the list will attempt to resize itself so that all its items are visible.

HTML param name/value: "VisibleRows"/int

showListAction(JCActionEvent)

Displays the list if it is not visible.

  public final static int COMBOBOX_SIMPLE

  public final static int COMBOBOX_DROPDOWN

  public final static int COMBOBOX_DROPDOWN_LIST

  protected JCVector itemListeners

List of JCItemEvent listeners

  protected JCVector actionListeners

List of JCActionEvent listeners

  protected JCVector listeners

List of JCComboBoxEvent listeners

  protected final static int BEGIN

  protected final static int END

  public JCComboBox()

Creates an empty ComboBox. No parameters are read from an HTML file.

  public JCComboBox(JCVector items)

Creates an empty ComboBox with the specified list items.

  public JCComboBox(String items[],
                    String name)

Creates a comboBox with the specified items and name. No parameters are read from an HTML file.

  public JCComboBox(JCVector items,
                    Applet applet,
                    String name)

Creates a comboBox which reads parameters from the applet's HTML file.

Parameters:

applet - the applet whose PARAM tags are to be read

name - if this is not null, only parameters preceded by this name are read

See Also:

getParameter

  protected void getParameters()

Reads the parameter values from the HTML page using the component's applet. The values will override those previously set.

Overrides:

getParameters in class JCContainer

  public JCTextField getTextField()

Gets the component to be used as the data entry field.

  public JCList getList()

Gets the list component.

  public JCArrowButton getButton()

Gets the button component.

  public synchronized void setText(String s)

Sets the text field's value to the specified string.

HTML param name/value: "Text"/string

  public synchronized String getText()

Gets the value of the text.

See Also:

setText

  public synchronized void setItems(String items[])

Sets the list's values as a list of Strings.

  public synchronized String[] getItems()

Gets the list's values as a list of Strings.

See Also:

setItems

  public int getStyle()

Gets the Style value.

See Also:

setStyle

  public void setStyle(int v)

Sets the style, which specifies whether the list is always displayed and whether the text field is editable. If the list is hidden, it can be displayed by pressing the arrow button or hitting the down or up arrow key. The value must be one of the following values:

 COMBOBOX_SIMPLE           list is always displayed, text field is editable
 COMBOBOX_DROPDOWN         list is hidden, text field is editable (default)
 COMBOBOX_DROPDOWN_LIST    list is hidden, text field is uneditable
 

Throws: IllegalArgumentException

If an invalid value is set

  public int getItemCount()

Returns the number of items in the list.

See Also:

getItem

  public Object getItem(int index)

Returns the item at the specified index in the list.

See Also:

getItemCount

  public synchronized void add(String item)

Adds an item to the list.

Throws: NullPointerException

If the item's value is null.

  public synchronized void remove(String item)

Removes the first occurrence of an item from the list.

Throws: IllegalArgumentException

If the item doesn't exist

  public synchronized void removeAll()

Removes all items from the list.

Overrides:

removeAll in class Container

See Also:

remove

  public synchronized String getSelectedItem()

Returns a String representation of the current choice.

See Also:

getSelectedIndex

  public int getSelectedIndex()

Returns the index of the currently selected item.

See Also:

getSelectedItem

  public synchronized void select(int pos)

Selects the item with the specified postion.

Throws: IllegalArgumentException

If the choice item position is invalid.

See Also:

getSelectedItem, getSelectedIndex

  public synchronized void select(Object item)

Selects the specified item.

See Also:

getSelectedItem, getSelectedIndex

  public synchronized Object[] getSelectedObjects()

Returns an array (length 1) containing the currently selected item.

See Also:

JCItemSelectable, getSelectedIndex

  public synchronized int[] getSelectedIndexes()

Returns an array (length 1) containing the currently selected item.

See Also:

JCItemSelectable

  public void setVisibleRows(int v)

Sets the number of visible rows; if set to 0 (default), the list will attempt to resize itself so that all its items are visible.

HTML param name/value: "VisibleRows"/int

See Also:

setItems

  public void addComboBoxListener(JCComboBoxListener l)

Adds the specified JCComboBoxEvent listener to receive events.

See Also:

JCComboBoxEvent

  public void removeComboBoxListener(JCComboBoxListener l)

Removes the specified listener so it no longer receives JCComboBoxEvents.

See Also:

addComboBoxListener

  public void addActionListener(JCActionListener l)

Adds the specified action listener to receive JCTextField action events.

See Also:

JCActionEvent

  public void removeActionListener(JCActionListener l)

Removes the specified action listener so it no longer receives action events.

See Also:

addActionListener

  public void addItemListener(JCItemListener l)

Adds the specified item listener to receive item selection events.

See Also:

JCItemEvent, JCItemListener

  public void removeItemListener(JCItemListener l)

Removes the specified item listener so it no longer receives item events.

  protected int preferredWidth()

Gets the subclass' preferred width (default: 100).

Overrides:

preferredWidth in class JCContainer

  protected int preferredHeight()

Gets the subclass' preferred height (default: 100).

Overrides:

preferredHeight in class JCContainer

  public void addNotify()

Creates the Panel's peer.

Overrides:

addNotify in class JCContainer

  public synchronized void layout()

Overrides:

layout in class Container

  public void showListAction(JCActionEvent ev)

Displays the list if it is not visible. A JCComboBoxEvent is first posted.

  protected void setTextAction(String value)

Copies the item to the text field, after first posting a JCComboBoxEvent to allow the application to disallow the selection or change its value. After the value is copied, an JCItemEvent is posted.

See Also:

addComboBoxListener, addItemListener

  protected JCComboBoxEvent postComboBoxEvent(int stage,
                                              Object value)

Posts a JCComboBoxEvent

Returns:

the posted event, or null if there are no listeners

See Also:

addComboBoxListener, JCComboBoxEvent

  public void itemStateChanged(JCItemEvent ev)

JCItemListener method - no-op

  public void keyPressed(KeyEvent ev)

  public void keyReleased(KeyEvent ev)

  public void keyTyped(KeyEvent ev)

  public void actionPerformed(JCActionEvent ev)

If the arrow button was clicked, calls showListAction to display the list.
If the list is displayed and the RETURN key was hit, calls setTextAction to copy the selected item to the text field.

See Also:

showListAction, setTextAction

  public void listItemSelectBegin(JCListEvent ev)

JCListListener method - no-op

  public void listItemSelectEnd(JCListEvent ev)

If the user clicked an item, calls setTextAction to copy the item to the text field.

See Also:

setTextAction

  public final void setLayout(LayoutManager mgr)

Sets the layout manager for this container. This method is overridden to prevent the layout mgr from being set.

Overrides:

setLayout in class Container

  public void paintInterior(Graphics gc)

Draws the shadows and title.

Overrides:

paintInterior in class JCContainer

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