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
TheList
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 thatlst = new List()
is equivalent tolist = 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 ofActionEvent
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
orActionListener
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 theList
class.-
Nested classes/interfaces inherited from class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
-
-
Field Summary
-
Fields inherited from class java.awt.Component
accessibleContext, 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
All Methods Instance Methods Concrete Methods Deprecated 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 byadd(String)
.void
addItem(String item, int index)
Deprecated.replaced byadd(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 byisMultipleMode()
.void
clear()
Deprecated.As of JDK version 1.1, replaced byremoveAll()
.int
countItems()
Deprecated.As of JDK version 1.1, replaced bygetItemCount()
.void
delItem(int position)
Deprecated.replaced byremove(String)
andremove(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 theAccessibleContext
associated with thisList
.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 asFooListener
s upon thisList
.Dimension
getMinimumSize()
Determines the minimum size of this scrolling list.Dimension
getMinimumSize(int rows)
Gets the minimum 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 methodmakeVisible
.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 byisIndexSelected(int)
.void
makeVisible(int index)
Makes the item at the specified index visible.Dimension
minimumSize()
Deprecated.As of JDK version 1.1, replaced bygetMinimumSize()
.Dimension
minimumSize(int rows)
Deprecated.As of JDK version 1.1, replaced bygetMinimumSize(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 bygetPreferredSize()
.Dimension
preferredSize(int rows)
Deprecated.As of JDK version 1.1, replaced bygetPreferredSize(int)
.protected void
processActionEvent(ActionEvent e)
Processes action events occurring on this component by dispatching them to any registeredActionListener
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 registeredItemListener
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 bysetMultipleMode(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
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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 forList(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 forList(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 ofmultipleMode
istrue
, then the user can select multiple items from the list. If it isfalse
, only one item at a time can be selected.- Parameters:
-
rows
- the number of items to show. -
multipleMode
- iftrue
, 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 classComponent
- 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 classComponent
- 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 bygetItemCount()
.
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 byadd(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 isnull
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 byadd(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
- ifindex
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 byremoveAll()
.
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 theposition
is less than 0 or greater thangetItemCount()-1
- Since:
- JDK1.1
- See Also:
-
add(String, int)
delItem
@Deprecated public void delItem(int position)
Deprecated. replaced byremove(String)
andremove(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)
getSelectedIndexes
public int[] getSelectedIndexes()
Gets the selected indexes on the list.- Returns:
- an array of the selected indexes on this scrolling list; if no item is selected, a zero-length array is returned.
- See Also:
-
select(int)
,deselect(int)
,isIndexSelected(int)
getSelectedItem
public String getSelectedItem()
Gets the selected item on this scrolling list.- Returns:
-
the selected item on the list; if no item is selected, or if multiple items are selected,
null
is returned. - See Also:
-
select(int)
,deselect(int)
,isIndexSelected(int)
getSelectedItems
public String[] getSelectedItems()
Gets the selected items on this scrolling list.- Returns:
- an array of the selected items on this scrolling list; if no item is selected, a zero-length array is returned.
- See Also:
-
select(int)
,deselect(int)
,isIndexSelected(int)
getSelectedObjects
public Object[] getSelectedObjects()
Gets the selected items on this scrolling list in an array of Objects.- Specified by:
-
getSelectedObjects
in interfaceItemSelectable
- Returns:
-
an array of
Object
s representing the selected items on this scrolling list; if no item is selected, a zero-length array is returned. - See Also:
-
getSelectedItems()
,ItemSelectable
select
public void select(int index)
Selects the item at the specified index in the scrolling list.Note that passing out of range parameters is invalid, and will result in unspecified behavior.
Note that this method should be primarily used to initially select an item in this component. Programmatically calling this method will not trigger an
ItemEvent
. The only way to trigger anItemEvent
is by user interaction.- Parameters:
-
index
- the position of the item to select - See Also:
-
getSelectedItem()
,deselect(int)
,isIndexSelected(int)
deselect
public void deselect(int index)
Deselects the item at the specified index.Note that passing out of range parameters is invalid, and will result in unspecified behavior.
If the item at the specified index is not selected, then the operation is ignored.
- Parameters:
-
index
- the position of the item to deselect - See Also:
-
select(int)
,getSelectedItem()
,isIndexSelected(int)
isIndexSelected
public boolean isIndexSelected(int index)
Determines if the specified item in this scrolling list is selected.- Parameters:
-
index
- the item to be checked - Returns:
-
true
if the specified item has been selected;false
otherwise - Since:
- JDK1.1
- See Also:
-
select(int)
,deselect(int)
isSelected
@Deprecated public boolean isSelected(int index)
Deprecated. As of JDK version 1.1, replaced byisIndexSelected(int)
.
getRows
public int getRows()
Gets the number of visible lines in this list. Note that once theList
has been created, this number will never change.- Returns:
- the number of visible lines in this scrolling list
isMultipleMode
public boolean isMultipleMode()
Determines whether this list allows multiple selections.- Returns:
-
true
if this list allows multiple selections; otherwise,false
- Since:
- JDK1.1
- See Also:
-
setMultipleMode(boolean)
allowsMultipleSelections
@Deprecated public boolean allowsMultipleSelections()
Deprecated. As of JDK version 1.1, replaced byisMultipleMode()
.
setMultipleMode
public void setMultipleMode(boolean b)
Sets the flag that determines whether this list allows multiple selections. When the selection mode is changed from multiple-selection to single-selection, the selected items change as follows: If a selected item has the location cursor, only that item will remain selected. If no selected item has the location cursor, all items will be deselected.- Parameters:
-
b
- iftrue
then multiple selections are allowed; otherwise, only one item from the list can be selected at once - Since:
- JDK1.1
- See Also:
-
isMultipleMode()
setMultipleSelections
@Deprecated public void setMultipleSelections(boolean b)
Deprecated. As of JDK version 1.1, replaced bysetMultipleMode(boolean)
.
getVisibleIndex
public int getVisibleIndex()
Gets the index of the item that was last made visible by the methodmakeVisible
.- Returns:
- the index of the item that was last made visible
- See Also:
-
makeVisible(int)
makeVisible
public void makeVisible(int index)
Makes the item at the specified index visible.- Parameters:
-
index
- the position of the item - See Also:
-
getVisibleIndex()
getPreferredSize
public Dimension getPreferredSize(int rows)
Gets the preferred dimensions for a list with the specified number of rows.- Parameters:
-
rows
- number of rows in the list - Returns:
- the preferred dimensions for displaying this scrolling list given that the specified number of rows must be visible
- Since:
- JDK1.1
- See Also:
-
Component.getPreferredSize()
preferredSize
@Deprecated public Dimension preferredSize(int rows)
Deprecated. As of JDK version 1.1, replaced bygetPreferredSize(int)
.
getPreferredSize
public Dimension getPreferredSize()
Gets the preferred size of this scrolling list.- Overrides:
-
getPreferredSize
in classComponent
- Returns:
- the preferred dimensions for displaying this scrolling list
- Since:
- JDK1.1
- See Also:
-
Component.getPreferredSize()
preferredSize
@Deprecated public Dimension preferredSize()
Deprecated. As of JDK version 1.1, replaced bygetPreferredSize()
.- Overrides:
-
preferredSize
in classComponent
getMinimumSize
public Dimension getMinimumSize(int rows)
Gets the minimum dimensions for a list with the specified number of rows.- Parameters:
-
rows
- number of rows in the list - Returns:
- the minimum dimensions for displaying this scrolling list given that the specified number of rows must be visible
- Since:
- JDK1.1
- See Also:
-
Component.getMinimumSize()
minimumSize
@Deprecated public Dimension minimumSize(int rows)
Deprecated. As of JDK version 1.1, replaced bygetMinimumSize(int)
.
getMinimumSize
public Dimension getMinimumSize()
Determines the minimum size of this scrolling list.- Overrides:
-
getMinimumSize
in classComponent
- Returns:
- the minimum dimensions needed to display this scrolling list
- Since:
- JDK1.1
- See Also:
-
Component.getMinimumSize()
minimumSize
@Deprecated public Dimension minimumSize()
Deprecated. As of JDK version 1.1, replaced bygetMinimumSize()
.- Overrides:
-
minimumSize
in classComponent
addItemListener
public void addItemListener(ItemListener l)
Adds the specified item listener to receive item events from this list. Item events are sent in response to user input, but not in response to calls toselect
ordeselect
. If listenerl
isnull
, no exception is thrown and no action is performed.Refer to AWT Threading Issues for details on AWT's threading model.
- Specified by:
-
addItemListener
in interfaceItemSelectable
- Parameters:
-
l
- the item listener - Since:
- JDK1.1
- See Also:
-
removeItemListener(java.awt.event.ItemListener)
,getItemListeners()
,select(int)
,deselect(int)
,ItemEvent
,ItemListener
removeItemListener
public void removeItemListener(ItemListener l)
Removes the specified item listener so that it no longer receives item events from this list. If listenerl
isnull
, no exception is thrown and no action is performed.Refer to AWT Threading Issues for details on AWT's threading model.
- Specified by:
-
removeItemListener
in interfaceItemSelectable
- Parameters:
-
l
- the item listener - Since:
- JDK1.1
- See Also:
-
addItemListener(java.awt.event.ItemListener)
,getItemListeners()
,ItemEvent
,ItemListener
getItemListeners
public ItemListener[] getItemListeners()
Returns an array of all the item listeners registered on this list.- Returns:
-
all of this list's
ItemListener
s or an empty array if no item listeners are currently registered - Since:
- 1.4
- See Also:
-
addItemListener(java.awt.event.ItemListener)
,removeItemListener(java.awt.event.ItemListener)
,ItemEvent
,ItemListener
addActionListener
public void addActionListener(ActionListener l)
Adds the specified action listener to receive action events from this list. Action events occur when a user double-clicks on a list item or types Enter when the list has the keyboard focus.If listener
l
isnull
, no exception is thrown and no action is performed.Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the action listener - Since:
- JDK1.1
- See Also:
-
removeActionListener(java.awt.event.ActionListener)
,getActionListeners()
,ActionEvent
,ActionListener
removeActionListener
public void removeActionListener(ActionListener l)
Removes the specified action listener so that it no longer receives action events from this list. Action events occur when a user double-clicks on a list item. If listenerl
isnull
, no exception is thrown and no action is performed.Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the action listener - Since:
- JDK1.1
- See Also:
-
addActionListener(java.awt.event.ActionListener)
,getActionListeners()
,ActionEvent
,ActionListener
getActionListeners
public ActionListener[] getActionListeners()
Returns an array of all the action listeners registered on this list.- Returns:
-
all of this list's
ActionListener
s or an empty array if no action listeners are currently registered - Since:
- 1.4
- See Also:
-
addActionListener(java.awt.event.ActionListener)
,removeActionListener(java.awt.event.ActionListener)
,ActionEvent
,ActionListener
getListeners
public <T extends EventListener> T[] getListeners(Class<T> listenerType)
Returns an array of all the objects currently registered asFooListener
s upon thisList
.FooListener
s are registered using theaddFooListener
method.You can specify the
listenerType
argument with a class literal, such asFooListener.class
. For example, you can query aList
l
for its item listeners with the following code:ItemListener[] ils = (ItemListener[])(l.getListeners(ItemListener.class));
If no such listeners exist, this method returns an empty array.- Overrides:
-
getListeners
in classComponent
- Parameters:
-
listenerType
- the type of listeners requested; this parameter should specify an interface that descends fromjava.util.EventListener
- Returns:
-
an array of all objects registered as
FooListener
s on this list, or an empty array if no such listeners have been added - Throws:
-
ClassCastException
- iflistenerType
doesn't specify a class or interface that implementsjava.util.EventListener
- Since:
- 1.3
- See Also:
-
getItemListeners()
processEvent
protected void processEvent(AWTEvent e)
Processes events on this scrolling list. If an event is an instance ofItemEvent
, it invokes theprocessItemEvent
method. Else, if the event is an instance ofActionEvent
, it invokesprocessActionEvent
. If the event is not an item event or an action event, it invokesprocessEvent
on the superclass.Note that if the event parameter is
null
the behavior is unspecified and may result in an exception.- Overrides:
-
processEvent
in classComponent
- Parameters:
-
e
- the event - Since:
- JDK1.1
- See Also:
-
ActionEvent
,ItemEvent
,processActionEvent(java.awt.event.ActionEvent)
,processItemEvent(java.awt.event.ItemEvent)
processItemEvent
protected void processItemEvent(ItemEvent e)
Processes item events occurring on this list by dispatching them to any registeredItemListener
objects.This method is not called unless item events are enabled for this component. Item events are enabled when one of the following occurs:
- An
ItemListener
object is registered viaaddItemListener
. - Item events are enabled via
enableEvents
.
Note that if the event parameter is
null
the behavior is unspecified and may result in an exception.- Parameters:
-
e
- the item event - Since:
- JDK1.1
- See Also:
-
ItemEvent
,ItemListener
,addItemListener(java.awt.event.ItemListener)
,Component.enableEvents(long)
- An
processActionEvent
protected void processActionEvent(ActionEvent e)
Processes action events occurring on this component by dispatching them to any registeredActionListener
objects.This method is not called unless action events are enabled for this component. Action events are enabled when one of the following occurs:
- An
ActionListener
object is registered viaaddActionListener
. - Action events are enabled via
enableEvents
.
Note that if the event parameter is
null
the behavior is unspecified and may result in an exception.- Parameters:
-
e
- the action event - Since:
- JDK1.1
- See Also:
-
ActionEvent
,ActionListener
,addActionListener(java.awt.event.ActionListener)
,Component.enableEvents(long)
- An
paramString
protected String paramString()
Returns the parameter string representing the state of this scrolling list. This string is useful for debugging.- Overrides:
-
paramString
in classComponent
- Returns:
- the parameter string of this scrolling list
delItems
@Deprecated public 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.
getAccessibleContext
public AccessibleContext getAccessibleContext()
Gets theAccessibleContext
associated with thisList
. For lists, theAccessibleContext
takes the form of anAccessibleAWTList
. A newAccessibleAWTList
instance is created, if necessary.- Specified by:
-
getAccessibleContext
in interfaceAccessible
- Overrides:
-
getAccessibleContext
in classComponent
- Returns:
-
an
AccessibleAWTList
that serves as theAccessibleContext
of thisList
- Since:
- 1.3
-
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