List (Java Platform SE 7 )

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

Nested Classes
Modifier and Type Class and Description

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.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy

Nested Classes
Modifier and Type	Class and Description
`protected class`	`List.AccessibleAWTList` This class implements accessibility support for the `List` class.

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

Constructors
Constructor and Description
`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

Methods
Modifier and Type	Method and Description
`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 `FooListener`s 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, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAlignmentX, getAlignmentY, getBackground, getBaseline, getBaselineResizeBehavior, 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, getMousePosition, 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, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, 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, revalidate, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, update, validate

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - List
```
public List()
     throws HeadlessException
```
    Creates a new scrolling list. By default, there are four visible lines and multiple selections are not allowed. Note that this is a convenience method for List(0, false). Also note that the number of visible lines in the list cannot be changed after it has been created.
    
    Throws:
    
    HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
    See Also:
    GraphicsEnvironment.isHeadless()
  - List
```
public List(int rows)
     throws HeadlessException
```
    Creates a new scrolling list initialized with the specified number of visible lines. By default, multiple selections are not allowed. Note that this is a convenience method for List(rows, false). Also note that the number of visible rows in the list cannot be changed after it has been created.
    
    Parameters:
    rows - the number of items to show.
    
    Throws:
    
    HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
    Since:
    
    JDK1.1
    
    See Also:
    GraphicsEnvironment.isHeadless()
  - List
```
public List(int rows,
    boolean multipleMode)
     throws HeadlessException
```
    Creates a new scrolling list initialized to display the specified number of rows. Note that if zero rows are specified, then the list will be created with a default of four rows. Also note that the number of visible rows in the list cannot be changed after it has been created. If the value of multipleMode is true, then the user can select multiple items from the list. If it is false, only one item at a time can be selected.
    
    Parameters:
    rows - the number of items to show.
    multipleMode - if true, then multiple selections are allowed; otherwise, only one item can be selected at a time.
    
    Throws:
    
    HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
    See Also:
    GraphicsEnvironment.isHeadless()
- Method Detail
  - addNotify
```
public void addNotify()
```
    Creates the peer for the list. The peer allows us to modify the list's appearance without changing its functionality.
    
    Overrides:
    
    addNotify in class Component
    
    See Also:
    Component.isDisplayable(), Component.removeNotify(), Component.invalidate()
  - removeNotify
```
public void removeNotify()
```
    Removes the peer for this list. The peer allows us to modify the list's appearance without changing its functionality.
    
    Overrides:
    
    removeNotify in class Component
    
    See Also:
    Component.isDisplayable(), Component.addNotify()
  - getItemCount
```
public int getItemCount()
```
    Gets the number of items in the list.
    
    Returns:
    the number of items in the list
    Since:
    
    JDK1.1
    
    See Also:
    getItem(int)
  - countItems
```
@Deprecated
public int countItems()
```
    Deprecated. As of JDK version 1.1, replaced by getItemCount().
  - getItem
```
public String getItem(int index)
```
    Gets the item associated with the specified index.
    
    Parameters:
    index - the position of the item
    
    Returns:
    an item that is associated with the specified index
    See Also:
    getItemCount()
  - getItems
```
public String[] getItems()
```
    Gets the items in the list.
    
    Returns:
    a string array containing items of the list
    Since:
    
    JDK1.1
    
    See Also:
    select(int), deselect(int), isIndexSelected(int)
  - add
```
public void add(String item)
```
    Adds the specified item to the end of scrolling list.
    
    Parameters:
    item - the item to be added
    Since:
    
    JDK1.1
  - addItem
```
@Deprecated
public void addItem(String item)
```
    Deprecated. replaced by add(String).
  - add
```
public void add(String item,
       int index)
```
    Adds the specified item to the the scrolling list at the position indicated by the index. The index is zero-based. If the value of the index is less than zero, or if the value of the index is greater than or equal to the number of items in the list, then the item is added to the end of the list.
    
    Parameters:
    item - the item to be added; if this parameter is null then the item is treated as an empty string, ""
    index - the position at which to add the item
    Since:
    
    JDK1.1
  - addItem
```
@Deprecated
public void addItem(String item,
                      int index)
```
    Deprecated. replaced by add(String, int).
  - replaceItem
```
public void replaceItem(String newValue,
               int index)
```
    Replaces the item at the specified index in the scrolling list with the new string.
    
    Parameters:
    newValue - a new string to replace an existing item
    index - the position of the item to replace
    
    Throws:
    
    ArrayIndexOutOfBoundsException - if index is out of range
  - removeAll
```
public void removeAll()
```
    Removes all items from this list.
    
    Since:
    
    JDK1.1
    
    See Also:
    remove(java.lang.String), delItems(int, int)
  - clear
```
@Deprecated
public void clear()
```
    Deprecated. As of JDK version 1.1, replaced by removeAll().
  - remove
```
public void remove(String item)
```
    Removes the first occurrence of an item from the list. If the specified item is selected, and is the only selected item in the list, the list is set to have no selection.
    
    Parameters:
    item - the item to remove from the list
    
    Throws:
    
    IllegalArgumentException - if the item doesn't exist in the list
    Since:
    
    JDK1.1
  - remove
```
public void remove(int position)
```
    Removes the item at the specified position from this scrolling list. If the item with the specified position is selected, and is the only selected item in the list, the list is set to have no selection.
    
    Parameters:
    position - the index of the item to delete
    
    Throws:
    
    ArrayIndexOutOfBoundsException - if the position is less than 0 or greater than getItemCount()-1
    Since:
    
    JDK1.1
    
    See Also:
    add(String, int)
  - delItem
```
@Deprecated
public void delItem(int position)
```
    Deprecated. replaced by remove(String) and remove(int).
  - getSelectedIndex
```
public int getSelectedIndex()
```
    Gets the index of the selected item on the list,
    
    Returns:
    the index of the selected item; if no item is selected, or if multiple items are selected, -1 is returned.
    See Also:
    select(int), deselect(int), isIndexSelected(int)

Class List

Nested Class Summary

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

Field Summary

Fields inherited from class java.awt.Component

Fields inherited from interface java.awt.image.ImageObserver

Constructor Summary

Method Summary

Methods inherited from class java.awt.Component

Methods inherited from class java.lang.Object

Constructor Detail

List

List

List

Method Detail

addNotify

removeNotify

getItemCount

countItems

getItem

getItems

add

addItem

add

addItem

replaceItem

removeAll

clear

remove

remove

delItem

getSelectedIndex