java.awt
Class List

java.lang.Object   
  java.awt.Component   
      java.awt.List

All Implemented Interfaces:

ImageObserver , ItemSelectable , MenuContainer , Serializable , Accessible

public class List
extends Component   
implements ItemSelectable   , Accessible   

The List component presents the user with a scrolling list of text items. The list can be set up so that the user can choose either one item or multiple items.

For example, the code . . .

 List lst = new List(4, false);
 lst.add("Mercury");
 lst.add("Venus");
 lst.add("Earth");
 lst.add("JavaSoft");
 lst.add("Mars");
 lst.add("Jupiter");
 lst.add("Saturn");
 lst.add("Uranus");
 lst.add("Neptune");
 lst.add("Pluto");
 cnt.add(lst);
 

where cnt is a container, produces the following scrolling list:

If the List allows multiple selections, then clicking on an item that is already selected deselects it. In the preceding example, only one item from the scrolling list can be selected at a time, since the second argument when creating the new scrolling list is false. If the List does not allow multiple selections, selecting an item causes any other selected item to be deselected.

Note that the list in the example shown was created with four visible rows. Once the list has been created, the number of visible rows cannot be changed. A default List is created with four rows, so that lst = new List() is equivalent to list = new List(4, false).

Beginning with Java 1.1, the Abstract Window Toolkit sends the List object all mouse, keyboard, and focus events that occur over it. (The old AWT event model is being maintained only for backwards compatibility, and its use is discouraged.)

When an item is selected or deselected by the user, AWT sends an instance of ItemEvent to the list. When the user double-clicks on an item in a scrolling list, AWT sends an instance of ActionEvent to the list following the item event. AWT also generates an action event when the user presses the return key while an item in the list is selected.

If an application wants to perform some action based on an item in this list being selected or activated by the user, it should implement ItemListener or ActionListener as appropriate and register the new listener to receive events from this list.

For multiple-selection scrolling lists, it is considered a better user interface to use an external gesture (such as clicking on a button) to trigger the action.

Since:

JDK1.0

See Also:

ItemEvent , ItemListener , ActionEvent , ActionListener , Serialized Form

Nested Class Summary

protected class

List.AccessibleAWTList This class implements accessibility support for the List class.

Nested classes/interfaces inherited from class java.awt.Component

Component.AccessibleAWTComponent , Component.BltBufferStrategy , Component.FlipBufferStrategy

Field Summary

Fields inherited from class java.awt.Component

BOTTOM_ALIGNMENT , CENTER_ALIGNMENT , LEFT_ALIGNMENT , RIGHT_ALIGNMENT , TOP_ALIGNMENT

Fields inherited from interface java.awt.image.ImageObserver

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

Constructor Summary

List ()
Creates a new scrolling list.

List (int rows)
Creates a new scrolling list initialized with the specified number of visible lines.

List (int rows, boolean multipleMode)
Creates a new scrolling list initialized to display the specified number of rows.

Method Summary

void	add (String item) Adds the specified item to the end of scrolling list.
void	add (String item, int index) Adds the specified item to the the scrolling list at the position indicated by the index.
void	addActionListener (ActionListener l) Adds the specified action listener to receive action events from this list.
void	addItem (String item) Deprecated. replaced by add(String).
void	addItem (String item, int index) Deprecated. replaced by add(String, int).
void	addItemListener (ItemListener l) Adds the specified item listener to receive item events from this list.
void	addNotify () Creates the peer for the list.
boolean	allowsMultipleSelections () Deprecated. As of JDK version 1.1, replaced by isMultipleMode().
void	clear () Deprecated. As of JDK version 1.1, replaced by removeAll().
int	countItems () Deprecated. As of JDK version 1.1, replaced by getItemCount().
void	delItem (int position) Deprecated. replaced by remove(String) and remove(int).
void	delItems (int start, int end) Deprecated. As of JDK version 1.1, Not for public use in the future. This method is expected to be retained only as a package private method.
void	deselect (int index) Deselects the item at the specified index.
AccessibleContext	getAccessibleContext () Gets the AccessibleContext associated with this List.
ActionListener []	getActionListeners () Returns an array of all the action listeners registered on this list.
String	getItem (int index) Gets the item associated with the specified index.
int	getItemCount () Gets the number of items in the list.
ItemListener []	getItemListeners () Returns an array of all the item listeners registered on this list.
String []	getItems () Gets the items in the list.
<T extends EventListener > T[]	getListeners (Class <T> listenerType) Returns an array of all the objects currently registered as FooListeners upon this List.
Dimension	getMinimumSize () Determines the minimum size of this scrolling list.
Dimension	getMinimumSize (int rows) Gets the minumum dimensions for a list with the specified number of rows.
Dimension	getPreferredSize () Gets the preferred size of this scrolling list.
Dimension	getPreferredSize (int rows) Gets the preferred dimensions for a list with the specified number of rows.
int	getRows () Gets the number of visible lines in this list.
int	getSelectedIndex () Gets the index of the selected item on the list,
int[]	getSelectedIndexes () Gets the selected indexes on the list.
String	getSelectedItem () Gets the selected item on this scrolling list.
String []	getSelectedItems () Gets the selected items on this scrolling list.
Object []	getSelectedObjects () Gets the selected items on this scrolling list in an array of Objects.
int	getVisibleIndex () Gets the index of the item that was last made visible by the method makeVisible.
boolean	isIndexSelected (int index) Determines if the specified item in this scrolling list is selected.
boolean	isMultipleMode () Determines whether this list allows multiple selections.
boolean	isSelected (int index) Deprecated. As of JDK version 1.1, replaced by isIndexSelected(int).
void	makeVisible (int index) Makes the item at the specified index visible.
Dimension	minimumSize () Deprecated. As of JDK version 1.1, replaced by getMinimumSize().
Dimension	minimumSize (int rows) Deprecated. As of JDK version 1.1, replaced by getMinimumSize(int).
protected String	paramString () Returns the parameter string representing the state of this scrolling list.
Dimension	preferredSize () Deprecated. As of JDK version 1.1, replaced by getPreferredSize().
Dimension	preferredSize (int rows) Deprecated. As of JDK version 1.1, replaced by getPreferredSize(int).
protected void	processActionEvent (ActionEvent e) Processes action events occurring on this component by dispatching them to any registered ActionListener objects.
protected void	processEvent (AWTEvent e) Processes events on this scrolling list.
protected void	processItemEvent (ItemEvent e) Processes item events occurring on this list by dispatching them to any registered ItemListener objects.
void	remove (int position) Removes the item at the specified position from this scrolling list.
void	remove (String item) Removes the first occurrence of an item from the list.
void	removeActionListener (ActionListener l) Removes the specified action listener so that it no longer receives action events from this list.
void	removeAll () Removes all items from this list.
void	removeItemListener (ItemListener l) Removes the specified item listener so that it no longer receives item events from this list.
void	removeNotify () Removes the peer for this list.
void	replaceItem (String newValue, int index) Replaces the item at the specified index in the scrolling list with the new string.
void	select (int index) Selects the item at the specified index in the scrolling list.
void	setMultipleMode (boolean b) Sets the flag that determines whether this list allows multiple selections.
void	setMultipleSelections (boolean b) Deprecated. As of JDK version 1.1, replaced by setMultipleMode(boolean).

Methods inherited from class java.awt.Component

action , add , addComponentListener , addFocusListener , addHierarchyBoundsListener , addHierarchyListener , addInputMethodListener , addKeyListener , addMouseListener , addMouseMotionListener , addMouseWheelListener , addPropertyChangeListener , addPropertyChangeListener , applyComponentOrientation , areFocusTraversalKeysSet , bounds , checkImage , checkImage , coalesceEvents , contains , contains , createImage , createImage , createVolatileImage , createVolatileImage , deliverEvent , disable , disableEvents , dispatchEvent , doLayout , enable , enable , enableEvents , enableInputMethods , firePropertyChange