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javax.swing
Class JList

java.lang.Object
  |
  +--java.awt.Component
        |
        +--java.awt.Container
              |
              +--javax.swing.JComponent
                    |
                    +--javax.swing.JList

All Implemented Interfaces:

Accessible, ImageObserver, MenuContainer, Scrollable, Serializable

public class JList

extends JComponent

implements Scrollable, Accessible

A component that allows the user to select one or more objects from a list. A separate model, ListModel, represents the contents of the list. It's easy to display an array or vector of objects, using a JList constructor that builds a ListModel instance for you:

 // Create a JList that displays the strings in data[]

 String[] data = {"one", "two", "three", "four"};
 JList dataList = new JList(data);
 
 // The value of the JList model property is an object that provides
 // a read-only view of the data.  It was constructed automatically.

 for(int i = 0; i < dataList.getModel().getSize(); i++) {
     System.out.println(dataList.getModel().getElementAt(i));
 }

 // Create a JList that displays the superclass of JList.class.
 // We store the superclasses in a java.util.Vector.

 Vector superClasses = new Vector();
 Class rootClass = javax.swing.JList.class;
 for(Class cls = rootClass; cls != null; cls = cls.getSuperclass()) {
     superClasses.addElement(cls);
 }
 JList classList = new JList(superClasses);
 

JList doesn't support scrolling directly. To create a scrolling list you make the JList the viewport view of a JScrollPane. For example:

 JScrollPane scrollPane = new JScrollPane(dataList);
 // Or in two steps:
 JScrollPane scrollPane = new JScrollPane();
 scrollPane.getViewport().setView(dataList);
 

By default the JList selection model allows any combination of items to be selected at a time, using the constant MULTIPLE_INTERVAL_SELECTION. The selection state is actually managed by a separate delegate object, an instance of ListSelectionModel. However JList provides convenient properties for managing the selection.

 String[] data = {"one", "two", "three", "four"};
 JList dataList = new JList(data);

 dataList.setSelectedIndex(1);  // select "two"
 dataList.getSelectedValue();   // returns "two"
 

The contents of a JList can be dynamic, in other words, the list elements can change value and the size of the list can change after the JList has been created. The JList observes changes in its model with a swing.event.ListDataListener implementation. A correct implementation of ListModel notifies it's listeners each time a change occurs. The changes are characterized by a swing.event.ListDataEvent, which identifies the range of list indices that have been modified, added, or removed. Simple dynamic-content JList applications can use the DefaultListModel class to store list elements. This class implements the ListModel interface and provides the java.util.Vector API as well. Applications that need to provide custom ListModel implementations can subclass AbstractListModel, which provides basic ListDataListener support. For example:

 // This list model has about 2^16 elements.  Enjoy scrolling.

 
 ListModel bigData = new AbstractListModel() {
     public int getSize() { return Short.MAX_VALUE; }
     public Object getElementAt(int index) { return "Index " + index; }
 };

 JList bigDataList = new JList(bigData);

 // We don't want the JList implementation to compute the width
 // or height of all of the list cells, so we give it a string
 // that's as big as we'll need for any cell.  It uses this to
 // compute values for the fixedCellWidth and fixedCellHeight
 // properties.

 bigDataList.setPrototypeCellValue("Index 1234567890");
 

JList uses a java.awt.Component, provided by a delegate called the cellRendererer, to paint the visible cells in the list. The cell renderer component is used like a "rubber stamp" to paint each visible row. Each time the JList needs to paint a cell it asks the cell renderer for the component, moves it into place using setBounds() and then draws it by calling its paint method. The default cell renderer uses a JLabel component to render the string value of each component. You can substitute your own cell renderer, using code like this:

  // Display an icon and a string for each object in the list.

 
 class MyCellRenderer extends JLabel implements ListCellRenderer {
     final static ImageIcon longIcon = new ImageIcon("long.gif");
     final static ImageIcon shortIcon = new ImageIcon("short.gif");

     // This is the only method defined by ListCellRenderer.
     // We just reconfigure the JLabel each time we're called.

     public Component getListCellRendererComponent(
       JList list,
       Object value,            // value to display
       int index,               // cell index
       boolean isSelected,      // is the cell selected
       boolean cellHasFocus)    // the list and the cell have the focus
     {
         String s = value.toString();
         setText(s);
         setIcon((s.length() > 10) ? longIcon : shortIcon);
   	   if (isSelected) {
             setBackground(list.getSelectionBackground());
	       setForeground(list.getSelectionForeground());
	   }
         else {
	       setBackground(list.getBackground());
	       setForeground(list.getForeground());
	   }
	   setEnabled(list.isEnabled());
	   setFont(list.getFont());
         return this;
     }
 }

 String[] data = {"one", "two", "three", "four"};
 JList dataList = new JList(data);
 dataList.setCellRenderer(new MyCellRenderer());
 

JList doesn't provide any special support for handling double or triple (or N) mouse clicks however it's easy to handle them using a MouseListener. Use the JList method locationToIndex() to determine what cell was clicked. For example:

 final JList list = new JList(dataModel);
 MouseListener mouseListener = new MouseAdapter() {
     public void mouseClicked(MouseEvent e) {
         if (e.getClickCount() == 2) {
             int index = list.locationToIndex(e.getPoint());
             System.out.println("Double clicked on Item " + index);
          }
     }
 };
 list.addMouseListener(mouseListener);
 

Note that in this example the dataList is final because it's referred to by the anonymous MouseListener class.

For the keyboard keys used by this component in the standard look and feel (L&F) renditions, see the JList key assignments.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. A future release of Swing will provide support for long term persistence.

See How to Use Lists in The Java Tutorial for further documentation. Also see the article Advanced JList Programming in The Swing Connection.

See Also:

ListModel, AbstractListModel, DefaultListModel, ListSelectionModel, DefaultListSelectionModel, ListCellRenderer, Serialized Form

Inner Class Summary

protected class

JList.AccessibleJList This class implements accessibility support for the JList class.

Inner classes inherited from class javax.swing.JComponent

JComponent.AccessibleJComponent

Inner classes inherited from class java.awt.Container

Container.AccessibleAWTContainer

Inner classes inherited from class java.awt.Component

Component.AccessibleAWTComponent

Fields inherited from class javax.swing.JComponent

accessibleContext, listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW

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

JList()
Constructs a JList with an empty model.

JList(ListModel dataModel)
Constructs a JList that displays the elements in the specified, non-null model.

JList(Object[] listData)
Constructs a JList that displays the elements in the specified array.

JList(Vector listData)
Constructs a JList that displays the elements in the specified Vector.

Method Summary

void	addListSelectionListener(ListSelectionListener listener) Adds a listener to the list that's notified each time a change to the selection occurs.
void	addSelectionInterval(int anchor, int lead) Sets the selection to be the union of the specified interval with current selection.
void	clearSelection() Clears the selection - after calling this method isSelectionEmpty will return true.
protected ListSelectionModel	createSelectionModel() Returns an instance of DefaultListSelectionModel.
void	ensureIndexIsVisible(int index) Scrolls the viewport to make the specified cell completely visible.
protected void	fireSelectionValueChanged(int firstIndex, int lastIndex, boolean isAdjusting) Notifies JList ListSelectionListeners that the selection model has changed.
AccessibleContext	getAccessibleContext() Gets the AccessibleContext associated with this JList.
int	getAnchorSelectionIndex() Returns the first index argument from the most recent addSelectionModel or setSelectionInterval call.
Rectangle	getCellBounds(int index0, int index1) Returns the bounds of the specified range of items in JList coordinates.
ListCellRenderer	getCellRenderer() Returns the object that renders the list items.
int	getFirstVisibleIndex() Returns the index of the cell in the upper left corner of the JList or -1 if nothing is visible or the list is empty.
int	getFixedCellHeight() Returns the fixed cell height value -- the value specified by setting the fixedCellHeight property, rather than that calculated from the list elements.
int	getFixedCellWidth() Returns the fixed cell width value -- the value specified by setting the fixedCellWidth property, rather than that calculated from the list elements.
int	getLastVisibleIndex() Returns the index of the cell in the lower right corner of the JList or -1 if nothing is visible or the list is empty.
int	getLeadSelectionIndex() Returns the second index argument from the most recent addSelectionInterval or setSelectionInterval call.
int	getMaxSelectionIndex() Returns the largest selected cell index.
int	getMinSelectionIndex() Returns the smallest selected cell index.
ListModel	getModel() Returns the data model that holds the list of items displayed by the JList component.
Dimension	getPreferredScrollableViewportSize() Computes the size of the viewport needed to display visibleRowCount rows.
Object	getPrototypeCellValue() Returns the cell width of the "prototypical cell" -- a cell used for the calculation of cell widths, because it has the same value as all other list items.
int	getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction) Returns the block increment amount.
boolean	getScrollableTracksViewportHeight() Returns true if this JList is displayed in a JViewport and the viewport is taller than JList's preferred height; otherwise returns false.
boolean	getScrollableTracksViewportWidth() Returns true if this JList is displayed in a JViewport and the viewport is wider than JList's preferred width; otherwise returns false.
int	getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction) Returns the distance to scroll to expose the next or previous row (for vertical scrolling) or character (for horizontal scrolling).
int	getSelectedIndex() Returns the first selected index; returns -1 if there is no selected item.
int[]	getSelectedIndices() Returns an array of all of the selected indices in increasing order.
Object	getSelectedValue() Returns the first selected value, or null if the selection is empty.
Object[]	getSelectedValues() Returns an array of the values for the selected cells.
Color	getSelectionBackground() Returns the background color for selected cells.
Color	getSelectionForeground() Returns the selection foreground color.
int	getSelectionMode() Returns whether single-item or multiple-item selections are allowed.
ListSelectionModel	getSelectionModel() Returns the value of the current selection model.
ListUI	getUI() Returns the look and feel (L&F) object that renders this component.
String	getUIClassID() Returns the suffix used to construct the name of the look and feel (L&F) class used to render this component.
boolean	getValueIsAdjusting() Returns the value of the data model's isAdjusting property.
int	getVisibleRowCount() Returns the preferred number of visible rows.
Point	indexToLocation(int index) Returns the origin of the specified item in JList coordinates.
boolean	isSelectedIndex(int index) Returns true if the specified index is selected.
boolean	isSelectionEmpty() Returns true if nothing is selected.
int	locationToIndex(Point location) Converts a point in JList coordinates to the index of the cell at that location.
protected String	paramString() Returns a string representation of this JList.
void	removeListSelectionListener(ListSelectionListener listener) Removes a listener from the list that's notified each time a change to the selection occurs.
void	removeSelectionInterval(int index0, int index1) Sets the selection to be the set difference of the specified interval and the current selection.
void	setCellRenderer(ListCellRenderer cellRenderer) Sets the delegate that's used to paint each cell in the list.
void	setFixedCellHeight(int height) Sets the height of every cell in the list.
void	setFixedCellWidth(int width) Sets the width of every cell in the list.
void	setListData(Object[] listData) Constructs a ListModel from an array of objects and then applies setModel to it.
void	setListData(Vector listData) Constructs a ListModel from a Vector and then applies setModel to it.
void	setModel(ListModel model) Sets the model that represents the contents or "value" of the list and clears the list selection after notifying PropertyChangeListeners.
void	setPrototypeCellValue(Object prototypeCellValue) Computes the fixedCellWidth and fixedCellHeight properties by configuring the cellRenderer to index equals zero for the specified value and then computing the renderer component's preferred size.
void	setSelectedIndex(int index) Selects a single cell.
void	setSelectedIndices(int[] indices) Selects a set of cells.
void	setSelectedValue(Object anObject, boolean shouldScroll) Selects the specified object from the list.
void	setSelectionBackground(Color selectionBackground) Sets the background color for selected cells.
void	setSelectionForeground(Color selectionForeground) Sets the foreground color for selected cells.
void	setSelectionInterval(int anchor, int lead) Selects the specified interval.
void	setSelectionMode(int selectionMode) Determines whether single-item or multiple-item selections are allowed.
void	setSelectionModel(ListSelectionModel selectionModel) Sets the selectionModel for the list to a non-null ListSelectionModel implementation.
void	setUI(ListUI ui) Sets the look and feel (L&F) object that renders this component.
void	setValueIsAdjusting(boolean b) Sets the data model's isAdjusting property to true, so that a single event will be generated when all of the selection events have finished (for example, when the mouse is being dragged over the list in selection mode).
void	setVisibleRowCount(int visibleRowCount) Sets the preferred number of rows in the list that can be displayed without a scollbar, as determined by the nearest JViewport ancestor, if any.
void	updateUI() Sets the UI property with the "ListUI" from the current default UIFactory.

Methods inherited from class javax.swing.JComponent

addAncestorListener, addNotify, addPropertyChangeListener, addPropertyChangeListener, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAutoscrolls, getBorder, getBounds, getClientProperty, getComponentGraphics, getConditionForKeyStroke, getDebugGraphicsOptions, getGraphics, getHeight, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getVerifyInputWhenFocusTarget, getVisibleRect, getWidth, getX, getY, grabFocus, hasFocus, hide, isDoubleBuffered, isFocusCycleRoot, isFocusTraversable, isLightweightComponent, isManagingFocus, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isOptimizedDrawingEnabled, isPaintingTile, isPreferredSizeSet, isRequestFocusEnabled, isValidateRoot, paint, paintBorder, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processFocusEvent, processKeyBinding, processKeyEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setDebugGraphicsOptions, setDoubleBuffered, setEnabled, setFont, setForeground, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, update

Methods inherited from class java.awt.Container

add, add, add, add, add, addContainerListener, addImpl, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getLayout, insets, invalidate, isAncestorOf, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setLayout, validate, validateTree

Methods inherited from class java.awt.Component

action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, getBackground, getBounds, getColorModel, getComponentOrientation, getCursor, getDropTarget, getFont, getFontMetrics, getForeground, getGraphicsConfiguration, getInputContext, getInputMethodRequests, getLocale, getLocation, getLocationOnScreen, getName, getParent, getPeer, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, imageUpdate, inside, isDisplayable, isEnabled, isLightweight, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, processComponentEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, repaint, repaint, repaint, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setLocale, setLocation, setLocation, setName, setSize, setSize, show, show, size, toString, transferFocus

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

JList

public JList(ListModel dataModel)

Constructs a JList that displays the elements in the specified, non-null model. All JList constructors delegate to this one.

Parameters:

dataModel - the data model for this list

Throws:

IllegalArgumentException - if dataModel is null

JList

public JList(Object[] listData)

Constructs a JList that displays the elements in the specified array. This constructor just delegates to the ListModel constructor.

Parameters:

listData - the array of Objects to be loaded into the data model

JList

public JList(Vector listData)

Constructs a JList that displays the elements in the specified Vector. This constructor just delegates to the ListModel constructor.

Parameters:

listData - the Vector to be loaded into the data model

JList

public JList()

Constructs a JList with an empty model.

Method Detail

getUI

public ListUI getUI()

Returns the look and feel (L&F) object that renders this component.

Returns:

the ListUI object that renders this component

setUI

public void setUI(ListUI ui)

Sets the look and feel (L&F) object that renders this component.

Parameters:

ui - the ListUI L&F object

See Also:

UIDefaults.getUI(javax.swing.JComponent)

updateUI

public void updateUI()

Sets the UI property with the "ListUI" from the current default UIFactory. This method is called by the JList constructor and to update the list's look and feel at runtime.

Overrides:

updateUI in class JComponent

See Also:

UIManager.getUI(javax.swing.JComponent)

getUIClassID

public String getUIClassID()

Returns the suffix used to construct the name of the look and feel (L&F) class used to render this component.

Overrides:

getUIClassID in class JComponent

Returns:

the string "ListUI"

See Also:

JComponent.getUIClassID(), UIDefaults.getUI(javax.swing.JComponent)

getPrototypeCellValue

public Object getPrototypeCellValue()

Returns the cell width of the "prototypical cell" -- a cell used for the calculation of cell widths, because it has the same value as all other list items.

Returns:

the value of the prototypeCellValue property

See Also:

setPrototypeCellValue(java.lang.Object)

setPrototypeCellValue

public void setPrototypeCellValue(Object prototypeCellValue)

Computes the fixedCellWidth and fixedCellHeight properties by configuring the cellRenderer to index equals zero for the specified value and then computing the renderer component's preferred size. These properties are useful when the list is too long to allow JList to compute the width/height of each cell and there is a single cell value that is known to occupy as much space as any of the others.

Note that we do set the fixedCellWidth and fixedCellHeight properties here but only a prototypeCellValue PropertyChangeEvent is fired.

To see an example which sets this property, see the class description above.

The default value of this property is null.

This is a JavaBeans bound property.

Parameters:

prototypeCellValue - the value on which to base fixedCellWidth and fixedCellHeight

See Also:

getPrototypeCellValue(), setFixedCellWidth(int), setFixedCellHeight(int), JComponent.addPropertyChangeListener(java.beans.PropertyChangeListener)

getFixedCellWidth

public int getFixedCellWidth()

Returns the fixed cell width value -- the value specified by setting the fixedCellWidth property, rather than that calculated from the list elements.

Returns:

the fixed cell width

See Also:

setFixedCellWidth(int)

setFixedCellWidth

public void setFixedCellWidth(int width)

Sets the width of every cell in the list. If width is -1, cell widths are computed by applying getPreferredSize to the cellRenderer component for each list element.

The default value of this property is -1.

This is a JavaBeans bound property.

Parameters:

width - the width, in pixels, for all cells in this list

See Also:

getPrototypeCellValue(), setFixedCellWidth(int), JComponent.addPropertyChangeListener(java.beans.PropertyChangeListener)

getFixedCellHeight

public int getFixedCellHeight()

Returns the fixed cell height value -- the value specified by setting the fixedCellHeight property, rather than that calculated from the list elements.

Returns:

the fixed cell height, in pixels

See Also:

setFixedCellHeight(int)

setFixedCellHeight

public void setFixedCellHeight(int height)

Sets the height of every cell in the list. If height is -1, cell heights are computed by applying getPreferredSize to the cellRenderer component for each list element.

The default value of this property is -1.

This is a JavaBeans bound property.

Parameters:

height - an integer giving the height, in pixels, for all cells in this list

See Also:

getPrototypeCellValue(), setFixedCellWidth(int), JComponent.addPropertyChangeListener(java.beans.PropertyChangeListener)

getCellRenderer

public ListCellRenderer getCellRenderer()

Returns the object that renders the list items.

Returns:

the ListCellRenderer

See Also:

setCellRenderer(javax.swing.ListCellRenderer)

setCellRenderer

public void setCellRenderer(ListCellRenderer cellRenderer)

Sets the delegate that's used to paint each cell in the list. If prototypeCellValue was set then the fixedCellWidth and fixedCellHeight properties are set as well. Only one PropertyChangeEvent is generated however - for the cellRenderer property.

The default value of this property is provided by the ListUI delegate, i.e. by the look and feel implementation.

To see an example which sets the cell renderer, see the class description above.

This is a JavaBeans bound property.

Parameters:

cellRenderer - the ListCellRenderer that paints list cells

See Also:

getCellRenderer()

getSelectionForeground

public Color getSelectionForeground()

Returns the selection foreground color.

Returns:

the Color object for the foreground property

See Also:

setSelectionForeground(java.awt.Color), setSelectionBackground(java.awt.Color)

setSelectionForeground

public void setSelectionForeground(Color selectionForeground)

Sets the foreground color for selected cells. Cell renderers can use this color to render text and graphics for selected cells.

The default value of this property is defined by the look and feel implementation.

This is a JavaBeans bound property.

Parameters:

selectionForeground - the Color to use in the foreground for selected list items

See Also:

getSelectionForeground(), setSelectionBackground(java.awt.Color), JComponent.setForeground(java.awt.Color), JComponent.setBackground(java.awt.Color), JComponent.setFont(java.awt.Font)

getSelectionBackground

public Color getSelectionBackground()

Returns the background color for selected cells.

Returns:

the Color used for the background of selected list items

See Also:

setSelectionBackground(java.awt.Color), setSelectionForeground(java.awt.Color)

setSelectionBackground

public void setSelectionBackground(Color selectionBackground)

Sets the background color for selected cells. Cell renderers can use this color to the fill selected cells.

The default value of this property is defined by the look and feel implementation.

This is a JavaBeans bound property.

Parameters:

selectionBackground - the Color to use for the background of selected cells

See Also:

getSelectionBackground(), setSelectionForeground(java.awt.Color), JComponent.setForeground(java.awt.Color), JComponent.setBackground(java.awt.Color), JComponent.setFont(java.awt.Font)

getVisibleRowCount

public int getVisibleRowCount()

Returns the preferred number of visible rows.

Returns:

an integer indicating the preferred number of rows to display without using a scroll bar

See Also:

setVisibleRowCount(int)

setVisibleRowCount

public void setVisibleRowCount(int visibleRowCount)

Sets the preferred number of rows in the list that can be displayed without a scollbar, as determined by the nearest JViewport ancestor, if any. The value of this property only affects the value of the JList's preferredScrollableViewportSize.

The default value of this property is 8.

This is a JavaBeans bound property.

Parameters:

visibleRowCount - an integer specifying the preferred number of visible rows

See Also:

getVisibleRowCount(), JComponent.getVisibleRect(), JViewport

getFirstVisibleIndex

public int getFirstVisibleIndex()

Returns the index of the cell in the upper left corner of the JList or -1 if nothing is visible or the list is empty. Note that this cell may only be partially visible.

Returns:

the index of the first visible cell

See Also:

getLastVisibleIndex(), JComponent.getVisibleRect()

getLastVisibleIndex

public int getLastVisibleIndex()

Returns the index of the cell in the lower right corner of the JList or -1 if nothing is visible or the list is empty. Note that this cell may only be partially visible.

Returns:

the index of the last visible cell

See Also:

getLastVisibleIndex(), JComponent.getVisibleRect()

ensureIndexIsVisible

public void ensureIndexIsVisible(int index)

Scrolls the viewport to make the specified cell completely visible. Note, for this method to work, the JList must be displayed within a JViewport.

Parameters:

index - the index of the cell to make visible

See Also:

JComponent.scrollRectToVisible(java.awt.Rectangle), JComponent.getVisibleRect()

locationToIndex

public int locationToIndex(Point location)

Converts a point in JList coordinates to the index of the cell at that location. Returns -1 if there's no cell at the specified location.

Parameters:

location - the coordinates of the cell, relative to JList

Returns:

an integer -- the index of the cell at the given location, or -1.

indexToLocation

public Point indexToLocation(int index)

Returns the origin of the specified item in JList coordinates. Returns null if index isn't valid.

Parameters:

index - the index of the JList cell

Returns:

the origin of the index'th cell

getCellBounds

public Rectangle getCellBounds(int index0,
                               int index1)

Returns the bounds of the specified range of items in JList coordinates. Returns null if index isn't valid.

Parameters:

index0 - the index of the first JList cell in the range

index1 - the index of the last JList cell in the range

Returns:

the bounds of the indexed cells in pixels

getModel

public ListModel getModel()

Returns the data model that holds the list of items displayed by the JList component.

Returns:

the ListModel that provides the displayed list of items

See Also:

setModel(javax.swing.ListModel)

setModel

public void setModel(ListModel model)

Sets the model that represents the contents or "value" of the list and clears the list selection after notifying PropertyChangeListeners.

This is a JavaBeans bound property.

Parameters:

model - the ListModel that provides the list of items for display

Throws:

IllegalArgumentException - if model is null

See Also:

getModel()

setListData

public void setListData(Object[] listData)

Constructs a ListModel from an array of objects and then applies setModel to it.

Parameters:

listData - an array of Objects containing the items to display in the list

See Also:

setModel(javax.swing.ListModel)

setListData

public void setListData(Vector listData)

Constructs a ListModel from a Vector and then applies setModel to it.

Parameters:

listData - a Vector containing the items to display in the list

See Also:

setModel(javax.swing.ListModel)

createSelectionModel

protected ListSelectionModel createSelectionModel()

Returns an instance of DefaultListSelectionModel. This method is used by the constructor to initialize the selectionModel property.

Returns:

the ListSelectionModel used by this JList.

See Also:

setSelectionModel(javax.swing.ListSelectionModel), DefaultListSelectionModel

getSelectionModel

public ListSelectionModel getSelectionModel()

Returns the value of the current selection model. The selection model handles the task of making single selections, selections of contiguous ranges, and non-contiguous selections.

Returns:

the ListSelectionModel that implements list selections

See Also:

setSelectionModel(javax.swing.ListSelectionModel), ListSelectionModel

fireSelectionValueChanged

protected void fireSelectionValueChanged(int firstIndex,
                                         int lastIndex,
                                         boolean isAdjusting)

Notifies JList ListSelectionListeners that the selection model has changed. It's used to forward ListSelectionEvents from the selectionModel to the ListSelectionListeners added directly to the JList.

Parameters:

firstIndex - the first selected index

lastIndex - the last selected index

isAdjusting - true if multiple changes are being made

See Also:

addListSelectionListener(javax.swing.event.ListSelectionListener), removeListSelectionListener(javax.swing.event.ListSelectionListener), EventListenerList

addListSelectionListener

public void addListSelectionListener(ListSelectionListener listener)

Adds a listener to the list that's notified each time a change to the selection occurs. Listeners added directly to the JList will have their ListSelectionEvent.getSource() == this JList (instead of the ListSelectionModel).

Parameters:

listener - the ListSelectionListener to add

See Also:

getSelectionModel()

removeListSelectionListener

public void removeListSelectionListener(ListSelectionListener listener)

Removes a listener from the list that's notified each time a change to the selection occurs.

Parameters:

listener - the ListSelectionListener to remove

See Also:

addListSelectionListener(javax.swing.event.ListSelectionListener), getSelectionModel()

setSelectionModel

public void setSelectionModel(ListSelectionModel selectionModel)

Sets the selectionModel for the list to a non-null ListSelectionModel implementation. The selection model handles the task of making single selections, selections of contiguous ranges, and non-contiguous selections.

This is a JavaBeans bound property.

Parameters:

selectionModel - the ListSelectionModel that implements the selections

Throws:

IllegalArgumentException - if selectionModel is null

See Also:

getSelectionModel()

setSelectionMode

public void setSelectionMode(int selectionMode)

Determines whether single-item or multiple-item selections are allowed. The following selectionMode values are allowed:

• SINGLE_SELECTION Only one list index can be selected at a time. In this mode the setSelectionInterval and addSelectionInterval methods are equivalent, and only the second index argument is used.
• SINGLE_INTERVAL_SELECTION One contiguous index interval can be selected at a time. In this mode setSelectionInterval and addSelectionInterval are equivalent.
• MULTIPLE_INTERVAL_SELECTION In this mode, there's no restriction on what can be selected. This is the default.

Parameters:

selectionMode - an integer specifying the type of selections that are permissible

See Also:

getSelectionMode()

getSelectionMode

public int getSelectionMode()

Returns whether single-item or multiple-item selections are allowed.

Returns:

the value of the selectionMode property

See Also:

setSelectionMode(int)

getAnchorSelectionIndex

public int getAnchorSelectionIndex()

Returns the first index argument from the most recent addSelectionModel or setSelectionInterval call. This is a convenience method that just delegates to the selectionModel.

Returns:

the index that most recently anchored an interval selection

See Also:

ListSelectionModel.getAnchorSelectionIndex(), addSelectionInterval(int, int), setSelectionInterval(int, int), addListSelectionListener(javax.swing.event.ListSelectionListener)

getLeadSelectionIndex

public int getLeadSelectionIndex()

Returns the second index argument from the most recent addSelectionInterval or setSelectionInterval call. This is a convenience method that just delegates to the selectionModel.

Returns:

the index that most recently ended a interval selection

See Also:

ListSelectionModel.getLeadSelectionIndex(), addSelectionInterval(int, int), setSelectionInterval(int, int), addListSelectionListener(javax.swing.event.ListSelectionListener)

getMinSelectionIndex

public int getMinSelectionIndex()

Returns the smallest selected cell index. This is a convenience method that just delegates to the selectionModel.

Returns:

the smallest selected cell index

See Also:

ListSelectionModel.getMinSelectionIndex(), addListSelectionListener(javax.swing.event.ListSelectionListener)

getMaxSelectionIndex

public int getMaxSelectionIndex()

Returns the largest selected cell index. This is a convenience method that just delegates to the selectionModel.

Returns:

the largest selected cell index

See Also:

ListSelectionModel.getMaxSelectionIndex(), addListSelectionListener(javax.swing.event.ListSelectionListener)

isSelectedIndex

public boolean isSelectedIndex(int index)

Returns true if the specified index is selected. This is a convenience method that just delegates to the selectionModel.

Parameters:

index - index to be queried for selection state

Returns:

true if the specified index is selected

See Also:

ListSelectionModel.isSelectedIndex(int), setSelectedIndex(int), addListSelectionListener(javax.swing.event.ListSelectionListener)

isSelectionEmpty

public boolean isSelectionEmpty()

Returns true if nothing is selected. This is a convenience method that just delegates to the selectionModel.

Returns:

true if nothing is selected

See Also:

ListSelectionModel.isSelectionEmpty(), clearSelection(), addListSelectionListener(javax.swing.event.ListSelectionListener)

clearSelection

public void clearSelection()

Clears the selection - after calling this method isSelectionEmpty will return true. This is a convenience method that just delegates to the selectionModel.

See Also:

ListSelectionModel.clearSelection(), isSelectionEmpty(), addListSelectionListener(javax.swing.event.ListSelectionListener)

setSelectionInterval

public void setSelectionInterval(int anchor,
                                 int lead)

Selects the specified interval. Both the anchor and lead indices are included. It's not neccessary for anchor to be less than lead. This is a convenience method that just delegates to the selectionModel.

Parameters:

anchor - the first index to select

lead - the last index to select

See Also:

ListSelectionModel.setSelectionInterval(int, int), addSelectionInterval(int, int), removeSelectionInterval(int, int), addListSelectionListener(javax.swing.event.ListSelectionListener)

addSelectionInterval

public void addSelectionInterval(int anchor,
                                 int lead)

Sets the selection to be the union of the specified interval with current selection. Both the anchor and lead indices are included. It's not neccessary for anchor to be less than lead. This is a convenience method that just delegates to the selectionModel.

Parameters:

anchor - the first index to add to the selection

lead - the last index to add to the selection

See Also:

ListSelectionModel.addSelectionInterval(int, int), setSelectionInterval(int, int), removeSelectionInterval(int, int), addListSelectionListener(javax.swing.event.ListSelectionListener)

removeSelectionInterval

public void removeSelectionInterval(int index0,
                                    int index1)

Sets the selection to be the set difference of the specified interval and the current selection. Both the anchor and lead indices are removed. It's not neccessary for anchor to be less than lead. This is a convenience method that just delegates to the selectionModel.

Parameters:

anchor - the first index to remove from the selection

lead - the last index to remove from the selection

See Also:

ListSelectionModel.removeSelectionInterval(int, int), setSelectionInterval(int, int), addSelectionInterval(int, int), addListSelectionListener(javax.swing.event.ListSelectionListener)

setValueIsAdjusting

public void setValueIsAdjusting(boolean b)

Sets the data model's isAdjusting property to true, so that a single event will be generated when all of the selection events have finished (for example, when the mouse is being dragged over the list in selection mode).

Parameters:

b - the boolean value for the property value

See Also:

ListSelectionModel.setValueIsAdjusting(boolean)

getValueIsAdjusting

public boolean getValueIsAdjusting()

Returns the value of the data model's isAdjusting property. This value is true if multiple changes are being made.

Returns:

true if multiple selection-changes are occurring, as when the mouse is being dragged over the list

See Also:

ListSelectionModel.getValueIsAdjusting()

getSelectedIndices

public int[] getSelectedIndices()

Returns an array of all of the selected indices in increasing order.

Returns:

all of the selected indices, in increasing order

See Also:

removeSelectionInterval(int, int), addListSelectionListener(javax.swing.event.ListSelectionListener)

setSelectedIndex

public void setSelectedIndex(int index)

Selects a single cell.

Parameters:

index - the index of the one cell to select

See Also:

ListSelectionModel.setSelectionInterval(int, int), isSelectedIndex(int), addListSelectionListener(javax.swing.event.ListSelectionListener)

setSelectedIndices

public void setSelectedIndices(int[] indices)

Selects a set of cells.

Parameters:

indices - an array of the indices of the cells to select

See Also:

ListSelectionModel.addSelectionInterval(int, int), isSelectedIndex(int), addListSelectionListener(javax.swing.event.ListSelectionListener)

getSelectedValues

public Object[] getSelectedValues()

Returns an array of the values for the selected cells. The returned values are sorted in increasing index order.

Returns:

the selected values

See Also:

isSelectedIndex(int), getModel(), addListSelectionListener(javax.swing.event.ListSelectionListener)

getSelectedIndex

public int getSelectedIndex()

Returns the first selected index; returns -1 if there is no selected item.

Returns:

the value of getMinSelectionIndex

See Also:

getMinSelectionIndex(), addListSelectionListener(javax.swing.event.ListSelectionListener)

getSelectedValue

public Object getSelectedValue()

Returns the first selected value, or null if the selection is empty.

Returns:

the first selected value

See Also:

getMinSelectionIndex(), getModel(), addListSelectionListener(javax.swing.event.ListSelectionListener)

setSelectedValue

public void setSelectedValue(Object anObject,
                             boolean shouldScroll)

Selects the specified object from the list.

Parameters:

anObject - the object to select

shouldScroll - true if the list should scroll to display the selected object, if one exists; otherwise false

getPreferredScrollableViewportSize

public Dimension getPreferredScrollableViewportSize()

Computes the size of the viewport needed to display visibleRowCount rows. This is trivial if fixedCellWidth and fixedCellHeight were specified. Note that they can be specified implicitly with the prototypeCellValue property. If fixedCellWidth wasn't specified, it's computed by finding the widest list element. If fixedCellHeight wasn't specified then we resort to heuristics:

• If the model isn't empty we just multiply the height of the first row by visibleRowCount.
• If the model is empty, (JList.getModel().getSize() == 0), then we just allocate 16 pixels per visible row, and 256 pixels for the width (unless fixedCellWidth was set), and hope for the best.

Specified by:

getPreferredScrollableViewportSize in interface Scrollable

Returns:

a dimension containing the size of the viewport needed to display visibleRowCount rows

See Also:

getPreferredScrollableViewportSize(), setPrototypeCellValue(java.lang.Object)

getScrollableUnitIncrement

public int getScrollableUnitIncrement(Rectangle visibleRect,
                                      int orientation,
                                      int direction)

Returns the distance to scroll to expose the next or previous row (for vertical scrolling) or character (for horizontal scrolling). For horizontal scrolling: return the lists font size or 1 if the font is null. We're using the font size instead of the width of some canonical string, e.g. "m", because it's cheaper.

For verticaL scrolling: if we're scrolling downwards (direction is greater than 0), and the first row is completely visible with respect to visibleRect, then return its height. If we're scrolling downwards and the first row is only partially visible, return the height of the visible part of the first row. Similarly if we're scrolling upwards we return the height of the row above the first row, unless the first row is partially visible.

Note that the value of visibleRect must be the equal to this.getVisibleRect().

Specified by:

getScrollableUnitIncrement in interface Scrollable

Parameters:

visibleRect - the visible rectangle

orientation - HORIZONTAL or VERTICAL

direction - if <= 0, then scroll UP; if > 0, then scroll DOWN

Returns:

the distance, in pixels, to scroll to expose the next or previous unit

Throws:

IllegalArgumentException - if visibleRect is null, or orientation isn't one of SwingConstants.VERTICAL, SwingConstants.HORIZONTAL.

See Also:

Scrollable.getScrollableUnitIncrement(java.awt.Rectangle, int, int)

getScrollableBlockIncrement

public int getScrollableBlockIncrement(Rectangle visibleRect,
                                       int orientation,
                                       int direction)

Returns the block increment amount.

Specified by:

getScrollableBlockIncrement in interface Scrollable

Parameters:

visibleRect - the visible rectangle

orientation - HORIZONTAL or VERTICAL

direction - if <= 0, then scroll UP; if > 0, then scroll DOWN

Returns:

the visibleRect.height or visibleRect.width per the orientation

Throws:

IllegalArgumentException - if visibleRect is null, or orientation isn't one of SwingConstants.VERTICAL, SwingConstants.HORIZONTAL.

See Also:

Scrollable.getScrollableUnitIncrement(java.awt.Rectangle, int, int)

getScrollableTracksViewportWidth

public boolean getScrollableTracksViewportWidth()

Returns true if this JList is displayed in a JViewport and the viewport is wider than JList's preferred width; otherwise returns false. If false, then don't track the viewport's width. This allows horizontal scrolling if the JViewport is itself embedded in a JScrollPane.

Specified by:

getScrollableTracksViewportWidth in interface Scrollable

Returns:

true if viewport is wider than the JList's preferred width, otherwise false

See Also:

Scrollable.getScrollableTracksViewportWidth()

getScrollableTracksViewportHeight

public boolean getScrollableTracksViewportHeight()

Returns true if this JList is displayed in a JViewport and the viewport is taller than JList's preferred height; otherwise returns false. If false, then don't track the viewport's height. This allows vertical scrolling if the JViewport is itself embedded in a JScrollPane.

Specified by:

getScrollableTracksViewportHeight in interface Scrollable

Returns:

true if viewport is taller than Jlist's preferred height, otherwise false

See Also:

Scrollable.getScrollableTracksViewportHeight()

paramString

protected String paramString()

Returns a string representation of this JList. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be null.

Overrides:

paramString in class JComponent

Returns:

a string representation of this JList.

getAccessibleContext

public AccessibleContext getAccessibleContext()

Gets the AccessibleContext associated with this JList. For JLists, the AccessibleContext takes the form of an AccessibleJList. A new AccessibleJList instance is created if necessary.

Specified by:

getAccessibleContext in interface Accessible

Overrides:

getAccessibleContext in class JComponent

Returns:

an AccessibleJList that serves as the AccessibleContext of this JList