java.awt
Class List

java.lang.Object
  |
  +--java.awt.Component
        |
        +--java.awt.List
All Implemented Interfaces:
Accessible, ImageObserver, ItemSelectable, MenuContainer, Serializable
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("hostname");
 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:

Clicking on an item that isn't selected selects it. 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. Selecting an item causes any other selected item to be automatically 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 inherited from class java.awt.Component
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.
 EventListener[] getListeners(Class 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()
    Returns the selected items on the 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)
    Remove 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, firePropertyChange, firePropertyChange, getAlignmentX, getAlignmentY, getBackground, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeys, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMouseListeners, getMouseMotionListeners, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, invalidate, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusCycleRoot, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isOpaque, isShowing, isValid, isVisible, keyDown, keyUp, layout, list, list, list, list, list, locate, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paint, paintAll, postEvent, prepareImage, prepareImage, print, printAll, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setName, setSize, setSize, setVisible, show, show, size, toString, transfer