- java.lang.Object
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- java.awt.Component
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- java.awt.List
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- All Implemented Interfaces:
ImageObserver,ItemSelectable,MenuContainer,Serializable,Accessible
public class List extends Component implements ItemSelectable, Accessible
TheListcomponent 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
cntis 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
Listis 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
Listobject 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
ItemEventto the list. When the user double-clicks on an item in a scrolling list, AWT sends an instance ofActionEventto 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
ItemListenerorActionListeneras 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:
- 1.0
- See Also:
ItemEvent,ItemListener,ActionEvent,ActionListener, Serialized Form
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Nested Class Summary
Nested Classes Modifier and Type Class Description protected classList.AccessibleAWTListThis class implements accessibility support for theListclass.-
Nested classes/interfaces declared in class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
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Field Summary
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Fields declared in class java.awt.Component
accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
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Fields declared in interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
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Constructor Summary
Constructors Constructor 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.
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Method Summary
All Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description voidadd(String item)Adds the specified item to the end of scrolling list.voidadd(String item, int index)Adds the specified item to the scrolling list at the position indicated by the index.voidaddActionListener(ActionListener l)Adds the specified action listener to receive action events from this list.voidaddItem(String item)Deprecated.replaced byadd(String).voidaddItem(String item, int index)Deprecated.replaced byadd(String, int).voidaddItemListener(ItemListener l)Adds the specified item listener to receive item events from this list.voidaddNotify()Creates the peer for the list.booleanallowsMultipleSelections()Deprecated.As of JDK version 1.1, replaced byisMultipleMode().voidclear()Deprecated.As of JDK version 1.1, replaced byremoveAll().intcountItems()Deprecated.As of JDK version 1.1, replaced bygetItemCount().voiddelItem(int position)Deprecated.replaced byremove(String)andremove(int).voiddelItems(int start, int end)Deprecated.As of JDK version 1.1, Not for public use in the future.voiddeselect(int index)Deselects the item at the specified index.AccessibleContextgetAccessibleContext()Gets theAccessibleContextassociated with thisList.ActionListener[]getActionListeners()Returns an array of all the action listeners registered on this list.StringgetItem(int index)Gets the item associated with the specified index.intgetItemCount()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 asFooListeners upon thisList.DimensiongetMinimumSize()Determines the minimum size of this scrolling list.DimensiongetMinimumSize(int rows)Gets the minimum dimensions for a list with the specified number of rows.DimensiongetPreferredSize()Gets the preferred size of this scrolling list.DimensiongetPreferredSize(int rows)Gets the preferred dimensions for a list with the specified number of rows.intgetRows()Gets the number of visible lines in this list.intgetSelectedIndex()Gets the index of the selected item on the list,int[]getSelectedIndexes()Gets the selected indexes on the list.StringgetSelectedItem()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.intgetVisibleIndex()Gets the index of the item that was last made visible by the methodmakeVisible.booleanisIndexSelected(int index)Determines if the specified item in this scrolling list is selected.booleanisMultipleMode()Determines whether this list allows multiple selections.booleanisSelected(int index)Deprecated.As of JDK version 1.1, replaced byisIndexSelected(int).voidmakeVisible(int index)Makes the item at the specified index visible.DimensionminimumSize()Deprecated.As of JDK version 1.1, replaced bygetMinimumSize().DimensionminimumSize(int rows)Deprecated.As of JDK version 1.1, replaced bygetMinimumSize(int).protected StringparamString()Returns the parameter string representing the state of this scrolling list.DimensionpreferredSize()Deprecated.As of JDK version 1.1, replaced bygetPreferredSize().DimensionpreferredSize(int rows)Deprecated.As of JDK version 1.1, replaced bygetPreferredSize(int).protected voidprocessActionEvent(ActionEvent e)Processes action events occurring on this component by dispatching them to any registeredActionListenerobjects.protected voidprocessEvent(AWTEvent e)Processes events on this scrolling list.protected voidprocessItemEvent(ItemEvent e)Processes item events occurring on this list by dispatching them to any registeredItemListenerobjects.voidremove(int position)Removes the item at the specified position from this scrolling list.voidremove(String item)Removes the first occurrence of an item from the list.voidremoveActionListener(ActionListener l)Removes the specified action listener so that it no longer receives action events from this list.voidremoveAll()Removes all items from this list.voidremoveItemListener(ItemListener l)Removes the specified item listener so that it no longer receives item events from this list.voidremoveNotify()Removes the peer for this list.voidreplaceItem(String newValue, int index)Replaces the item at the specified index in the scrolling list with the new string.voidselect(int index)Selects the item at the specified index in the scrolling list.voidsetMultipleMode(boolean b)Sets the flag that determines whether this list allows multiple selections.voidsetMultipleSelections(boolean b)Deprecated.As of JDK version 1.1, replaced bysetMultipleMode(boolean).-
Methods declared in 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, 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, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, revalidate, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setMixingCutoutShape, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, update, validate
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Constructor Detail
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List
public List() throws HeadlessExceptionCreates 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()
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List
public List(int rows) throws HeadlessExceptionCreates 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:
- 1.1
- See Also:
GraphicsEnvironment.isHeadless()
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List
public List(int rows, boolean multipleMode) throws HeadlessExceptionCreates 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 ofmultipleModeistrue, 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()
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Method Detail
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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:
addNotifyin classComponent- See Also:
Component.isDisplayable(),Component.removeNotify(),Component.invalidate()
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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:
removeNotifyin classComponent- See Also:
Component.isDisplayable(),Component.addNotify()
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getItemCount
public int getItemCount()
Gets the number of items in the list.- Returns:
- the number of items in the list
- Since:
- 1.1
- See Also:
getItem(int)
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countItems
@Deprecated public int countItems()
Deprecated.As of JDK version 1.1, replaced bygetItemCount().Returns the number of items in the list.- Returns:
- the number of items in the list
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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()
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getItems
public String[] getItems()
Gets the items in the list.- Returns:
- a string array containing items of the list
- Since:
- 1.1
- See Also:
select(int),deselect(int),isIndexSelected(int)
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add
public void add(String item)
Adds the specified item to the end of scrolling list.- Parameters:
item- the item to be added- Since:
- 1.1
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addItem
@Deprecated public void addItem(String item)
Deprecated.replaced byadd(String).Adds the specified item to the end of the list.- Parameters:
item- the item to be added
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add
public void add(String item, int index)
Adds the specified item to 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 isnullthen the item is treated as an empty string,""index- the position at which to add the item- Since:
- 1.1
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addItem
@Deprecated public void addItem(String item, int index)
Deprecated.replaced byadd(String, int).Adds the specified item to the list at the position indicated by the index.- Parameters:
item- the item to be addedindex- the position at which to add the item
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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 itemindex- the position of the item to replace- Throws:
ArrayIndexOutOfBoundsException- ifindexis out of range
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removeAll
public void removeAll()
Removes all items from this list.- Since:
- 1.1
- See Also:
remove(java.lang.String),delItems(int, int)
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clear
@Deprecated public void clear()
Deprecated.As of JDK version 1.1, replaced byremoveAll().
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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:
- 1.1
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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 thepositionis less than 0 or greater thangetItemCount()-1- Since:
- 1.1
- See Also:
add(String, int)
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delItem
@Deprecated public void delItem(int position)
Deprecated.replaced byremove(String)andremove(int).Removes the item at the specified position.- Parameters:
position- the index of the item to delete
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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,
-1is returned. - See Also:
select(int),deselect(int),isIndexSelected(int)
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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)
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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,
nullis returned. - See Also:
select(int),deselect(int),isIndexSelected(int)
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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)
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getSelectedObjects
public Object[] getSelectedObjects()
Gets the selected items on this scrolling list in an array of Objects.- Specified by:
getSelectedObjectsin interfaceItemSelectable- Returns:
- an array of
Objects representing the selected items on this scrolling list; if no item is selected, a zero-length array is returned. - See Also:
getSelectedItems(),ItemSelectable
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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 anItemEventis by user interaction.- Parameters:
index- the position of the item to select- See Also:
getSelectedItem(),deselect(int),isIndexSelected(int)
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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)
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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:
trueif the specified item has been selected;falseotherwise- Since:
- 1.1
- See Also:
select(int),deselect(int)
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isSelected
@Deprecated public boolean isSelected(int index)
Deprecated.As of JDK version 1.1, replaced byisIndexSelected(int).Determines if the specified item in the list is selected.- Parameters:
index- specifies the item to be checked- Returns:
trueif the item is selected; otherwisefalse
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getRows
public int getRows()
Gets the number of visible lines in this list. Note that once theListhas been created, this number will never change.- Returns:
- the number of visible lines in this scrolling list
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isMultipleMode
public boolean isMultipleMode()
Determines whether this list allows multiple selections.- Returns:
trueif this list allows multiple selections; otherwise,false- Since:
- 1.1
- See Also:
setMultipleMode(boolean)
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allowsMultipleSelections
@Deprecated public boolean allowsMultipleSelections()
Deprecated.As of JDK version 1.1, replaced byisMultipleMode().Determines whether this list allows multiple selections.- Returns:
trueif this list allows multiple selections; otherwisefalse
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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- iftruethen multiple selections are allowed; otherwise, only one item from the list can be selected at once- Since:
- 1.1
- See Also:
isMultipleMode()
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setMultipleSelections
@Deprecated public void setMultipleSelections(boolean b)
Deprecated.As of JDK version 1.1, replaced bysetMultipleMode(boolean).Enables or disables multiple selection mode for this list.- Parameters:
b-trueto enable multiple mode,falseotherwise
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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)
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makeVisible
public void makeVisible(int index)
Makes the item at the specified index visible.- Parameters:
index- the position of the item- See Also:
getVisibleIndex()
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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:
- 1.1
- See Also:
Component.getPreferredSize()
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preferredSize
@Deprecated public Dimension preferredSize(int rows)
Deprecated.As of JDK version 1.1, replaced bygetPreferredSize(int).Returns the preferred size of this component assuming it has the specified number of rows.- Parameters:
rows- the number of rows- Returns:
- the preferred dimensions for displaying this list
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getPreferredSize
public Dimension getPreferredSize()
Gets the preferred size of this scrolling list.- Overrides:
getPreferredSizein classComponent- Returns:
- the preferred dimensions for displaying this scrolling list
- Since:
- 1.1
- See Also:
Component.getPreferredSize()
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preferredSize
@Deprecated public Dimension preferredSize()
Deprecated.As of JDK version 1.1, replaced bygetPreferredSize().Description copied from class:ComponentReturns the component's preferred size.- Overrides:
preferredSizein classComponent- Returns:
- the component's preferred size
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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:
- 1.1
- See Also:
Component.getMinimumSize()
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minimumSize
@Deprecated public Dimension minimumSize(int rows)
Deprecated.As of JDK version 1.1, replaced bygetMinimumSize(int).Returns the minimum dimensions for the list with the specified number of rows.- Parameters:
rows- the number of rows in the list- Returns:
- the minimum dimensions for displaying this list
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getMinimumSize
public Dimension getMinimumSize()
Determines the minimum size of this scrolling list.- Overrides:
getMinimumSizein classComponent- Returns:
- the minimum dimensions needed to display this scrolling list
- Since:
- 1.1
- See Also:
Component.getMinimumSize()
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minimumSize
@Deprecated public Dimension minimumSize()
Deprecated.As of JDK version 1.1, replaced bygetMinimumSize().Description copied from class:ComponentReturns the minimum size of this component.- Overrides:
minimumSizein classComponent- Returns:
- the minimum size of this component
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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 toselectordeselect. If listenerlisnull, no exception is thrown and no action is performed.Refer to AWT Threading Issues for details on AWT's threading model.
- Specified by:
addItemListenerin interfaceItemSelectable- Parameters:
l- the item listener- Since:
- 1.1
- See Also:
removeItemListener(java.awt.event.ItemListener),getItemListeners(),select(int),deselect(int),ItemEvent,ItemListener
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removeItemListener
public void removeItemListener(ItemListener l)
Removes the specified item listener so that it no longer receives item events from this list. If listenerlisnull, no exception is thrown and no action is performed.Refer to AWT Threading Issues for details on AWT's threading model.
- Specified by:
removeItemListenerin interfaceItemSelectable- Parameters:
l- the item listener- Since:
- 1.1
- See Also:
addItemListener(java.awt.event.ItemListener),getItemListeners(),ItemEvent,ItemListener
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getItemListeners
public ItemListener[] getItemListeners()
Returns an array of all the item listeners registered on this list.- Returns:
- all of this list's
ItemListeners 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
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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
lisnull, 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:
- 1.1
- See Also:
removeActionListener(java.awt.event.ActionListener),getActionListeners(),ActionEvent,ActionListener
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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 listenerlisnull, 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:
- 1.1
- See Also:
addActionListener(java.awt.event.ActionListener),getActionListeners(),ActionEvent,ActionListener
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getActionListeners
public ActionListener[] getActionListeners()
Returns an array of all the action listeners registered on this list.- Returns:
- all of this list's
ActionListeners 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
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getListeners
public <T extends EventListener> T[] getListeners(Class<T> listenerType)
Returns an array of all the objects currently registered asFooListeners upon thisList.FooListeners are registered using theaddFooListenermethod.You can specify the
listenerTypeargument with a class literal, such asFooListener.class. For example, you can query aList lfor 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:
getListenersin classComponent- Type Parameters:
T- the type of the listeners- 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
FooListeners on this list, or an empty array if no such listeners have been added - Throws:
ClassCastException- iflistenerTypedoesn't specify a class or interface that implementsjava.util.EventListener- Since:
- 1.3
- See Also:
getItemListeners()
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processEvent
protected void processEvent(AWTEvent e)
Processes events on this scrolling list. If an event is an instance ofItemEvent, it invokes theprocessItemEventmethod. Else, if the event is an instance ofActionEvent, it invokesprocessActionEvent. If the event is not an item event or an action event, it invokesprocessEventon the superclass.Note that if the event parameter is
nullthe behavior is unspecified and may result in an exception.- Overrides:
processEventin classComponent- Parameters:
e- the event- Since:
- 1.1
- See Also:
ActionEvent,ItemEvent,processActionEvent(java.awt.event.ActionEvent),processItemEvent(java.awt.event.ItemEvent)
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processItemEvent
protected void processItemEvent(ItemEvent e)
Processes item events occurring on this list by dispatching them to any registeredItemListenerobjects.This method is not called unless item events are enabled for this component. Item events are enabled when one of the following occurs:
- An
ItemListenerobject is registered viaaddItemListener. - Item events are enabled via
enableEvents.
Note that if the event parameter is
nullthe behavior is unspecified and may result in an exception.- Parameters:
e- the item event- Since:
- 1.1
- See Also:
ItemEvent,ItemListener,addItemListener(java.awt.event.ItemListener),Component.enableEvents(long)
- An
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processActionEvent
protected void processActionEvent(ActionEvent e)
Processes action events occurring on this component by dispatching them to any registeredActionListenerobjects.This method is not called unless action events are enabled for this component. Action events are enabled when one of the following occurs:
- An
ActionListenerobject is registered viaaddActionListener. - Action events are enabled via
enableEvents.
Note that if the event parameter is
nullthe behavior is unspecified and may result in an exception.- Parameters:
e- the action event- Since:
- 1.1
- See Also:
ActionEvent,ActionListener,addActionListener(java.awt.event.ActionListener),Component.enableEvents(long)
- An
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paramString
protected String paramString()
Returns the parameter string representing the state of this scrolling list. This string is useful for debugging.- Overrides:
paramStringin classComponent- Returns:
- the parameter string of this scrolling list
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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.Deletes the list items in the specified index range.- Parameters:
start- the beginning index of the range to deleteend- the ending index of the range to delete
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getAccessibleContext
public AccessibleContext getAccessibleContext()
Gets theAccessibleContextassociated with thisList. For lists, theAccessibleContexttakes the form of anAccessibleAWTList. A newAccessibleAWTListinstance is created, if necessary.- Specified by:
getAccessibleContextin interfaceAccessible- Overrides:
getAccessibleContextin classComponent- Returns:
- an
AccessibleAWTListthat serves as theAccessibleContextof thisList - Since:
- 1.3
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