javax.swing
Class JList

java.lang.Object
  java.awt.Component
      java.awt.Container
          javax.swing.JComponent
              javax.swing.JList

All Implemented Interfaces:

ImageObserver , MenuContainer , Serializable , Accessible , Scrollable

public class JList
extends JComponent
implements Scrollable, Accessible

A component that displays a list of objects and allows the user to select one or more items. objects from a list. A separate model, ListModel, maintains represents the contents of the list.

It's easy to display an array or Vector vector of objects, using the a JList constructor that automatically builds a read-only ListModel instance for you:

 // Create a JList that displays strings from an array

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

 // Create a JList that displays the superclasses of JList.class, by
 // creating it with a Vector populated with this data

 Vector superClasses = new Vector();
 Class rootClass = javax.swing.JList.class;
 for(Class cls = rootClass; cls != null; cls = cls.getSuperclass()) {
 superClasses.addElement(cls);
 }
 JList myList = new JList(superClasses);
 
 // The automatically created model is stored in JList's "model"
 // property, which you can retrieve

 ListModel model = myList.getModel();
 for(int i = 0; i 
 // 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 < model.getSize(); i++) {
     System.out.println(model.getElementAt(i));
 }
 

A ListModel can be supplied directly to a JList by way of a constructor or the setModel method. The contents need not be static - the number of items, and the values of items can change over time. A correct ListModel implementation notifies the set of javax.swing.event.ListDataListeners that have been added to it, each time a change occurs. These changes are characterized by a javax.swing.event.ListDataEvent, which identifies the range of list indices that have been modified, added, or removed. JList's ListUI is responsible for keeping the visual representation up to date with changes, by listening to the model. 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);
 

Simple, dynamic-content, JList applications can use the DefaultListModel class to maintain list elements. This class implements the ListModel interface and also provides a java.util.Vector-like API. Applications that need a more custom ListModel implementation may instead wish to subclass AbstractListModel, which provides basic support for managing and notifying listeners. For example, a read-only implementation of AbstractListModel: 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.

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

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

The selection state of a JList is managed by another separate model, an instance of ListSelectionModel. JList is initialized with a selection model on construction, and also contains methods to query or set this selection model. Additionally, JList provides convenient methods for easily managing the selection. These methods, such as setSelectedIndex and getSelectedValue, are cover methods that take care of the details of interacting with the selection model. By default, JList's selection model is configured to allow any combination of items to be selected at a time; selection mode MULTIPLE_INTERVAL_SELECTION. The selection mode can be changed on the selection model directly, or via JList's cover method. Responsibility for updating the selection model in response to user gestures lies with the list's ListUI.

A correct ListSelectionModel implementation notifies the set of javax.swing.event.ListSelectionListeners that have been added to it each time a change to the selection occurs. These changes are characterized by a javax.swing.event.ListSelectionEvent, which identifies the range of the selection change.

The preferred way to listen for changes in list selection is to add ListSelectionListeners directly to the JList. JList then takes care of listening to the the selection model and notifying your listeners of change.

Responsibility for listening to selection changes in order to keep the list's visual representation up to date lies with the list's ListUI.

Painting of cells in a JList is handled by a delegate called a cell renderer, installed on the list as the cellRenderer property. The renderer provides a java.awt.Component that is used like a "rubber stamp" to paint the cells. Each time a cell needs to be painted, the list's ListUI asks the cell renderer for the component, moves it into place, and has it paint the contents of the cell by way of its paint method. A default cell renderer, which uses a JLabel component to render, is installed by the lists's ListUI.

 // 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, // the list
 Object value, // value to display
 int index, // cell index
 boolean isSelected, // is the cell selected
 boolean cellHasFocus) // does the cell have 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());
 setOpaque(true);
 return this;
 }
 }

 myList.setCellRenderer(new MyCellRenderer());
 

Another job for the cell renderer is in helping to determine sizing information for the list. By default, the list's ListUI determines the size of cells by asking the cell renderer for its preferred size for each list item. This can be expensive for large lists of items. To avoid these calculations, you can set a fixedCellWidth and fixedCellHeight on the list, or have these values calculated automatically based on a single prototype value:

 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. 

 JScrollPane scrollPane = new JScrollPane(myList);

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

 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);
 

Warning: Swing is not thread safe. For more information see Swing's Threading Policy .

Warning: Serialized objects of this class will not be compatible with future Swing releases. 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. 

 // 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());
         setOpaque(true);
         return this;
     }
 }

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

 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);
 

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. As of 1.4, support for long term storage of all JavaBeans ^TM has been added to the java.beans package. Please see XMLEncoder .

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 , DefaultListCellRenderer

Field Summary
static int	HORIZONTAL_WRAP           Indicates a "newspaper style" layout with the cells flowing horizontally then vertically.
static int	VERTICAL           Indicates a vertical layout of cells, in a single column; the default layout. layout: one column of cells.
static int	VERTICAL_WRAP           Indicates a "newspaper style" layout with the cells flowing vertically then horizontally.

Constructor Summary
JList ()           Constructs a JList with an empty, read-only, empty model.
JList ( ListModel           Constructs a JList that displays the elements from in the specified, non-null, 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           Adds a listener to the list, to be list that's notified each time a change to the selection occurs; the preferred way of listening for selection state changes. 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; selection - after calling this method, method isSelectionEmpty will return true.
protected   ListSelectionModel	createSelectionModel ()           Returns an instance of DefaultListSelectionModel; called during construction to initialize the list's selection model property. DefaultListSelectionModel.
void	ensureIndexIsVisible (int index)           Scrolls the list within an enclosing viewport to make the specified cell completely visible.
protected  void	fireSelectionValueChanged (int firstIndex, int lastIndex, boolean isAdjusting)           Notifies JList ListSelectionListeners added directly to that the list of selection changes made to the selection model. model has changed.
AccessibleContext	getAccessibleContext ()           Gets the AccessibleContext associated with this JList.
int	getAnchorSelectionIndex ()           Returns the anchor selection index. first index argument from the most recent addSelectionModel or setSelectionInterval call.
Rectangle	getCellBounds (int index0, int index1)           Returns the bounding rectangle, in bounds of the list's coordinate system, for the specified range of cells specified by the two indices. items in JList coordinates.
ListCellRenderer	getCellRenderer ()           Returns the object responsible for painting that renders the list items.
boolean	getDragEnabled ()           Returns whether or not automatic drag handling is enabled.           Gets the dragEnabled property.
JList.DropLocation	getDropLocation ()           Returns the location that this component should visually indicate as the drop location during a DnD operation over the component, or null if no location is to currently be shown. component.
DropMode	getDropMode ()           Returns the drop mode for this component.
int	getFirstVisibleIndex ()           Returns the smallest list index that is currently visible. of the first visible cell.
int	getFixedCellHeight ()           Returns the fixed cell height value of -- the value specified by setting the fixedCellHeight property. property, rather than that calculated from the list elements.
int	getFixedCellWidth ()           Returns the fixed cell width value of -- the value specified by setting the fixedCellWidth property. property, rather than that calculated from the list elements.
int	getLastVisibleIndex ()           Returns the largest list index that is currently visible. of the last visible cell.
int	getLayoutOrientation ()           Returns the layout orientation property for the list: VERTICAL JList.VERTICAL if the layout is a single column of cells, VERTICAL_WRAP or JList.VERTICAL_WRAP if the layout is "newspaper style" with the content flowing vertically then horizontally, horizontally or HORIZONTAL_WRAP JList.HORIZONTAL_WRAP if the layout is "newspaper style" with the content flowing horizontally then vertically.
int	getLeadSelectionIndex ()           Returns the lead selection index. second index argument from the most recent addSelectionInterval or setSelectionInterval call.
ListSelectionListener	getListSelectionListeners ()           Returns an array of all the ListSelectionListeners added to this JList by way of addListSelectionListener. with addListSelectionListener().
int	getMaxSelectionIndex ()           Returns the largest selected cell index, or -1 if the selection is empty. index.
int	getMinSelectionIndex ()           Returns the smallest selected cell index, or -1 if the selection is empty. index.
ListModel	getModel ()           Returns the data model that holds the list of items displayed by the JList component.
int	getNextMatch ( String  prefix, int startIndex, Position.Bias           Returns the next list element whose toString value that starts with the given a prefix.
Dimension	getPreferredScrollableViewportSize ()           Computes the size of the viewport needed to display visibleRowCount rows.
Object	getPrototypeCellValue ()           Returns the "prototypical" cell value width of the "prototypical cell" -- a value cell used to calculate a fixed width and height for cells. 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 distance to scroll to expose the next or previous block.
boolean	getScrollableTracksViewportHeight ()           Returns true if this JList is displayed in a JViewport and the viewport is taller than the list's JList's preferred height, or if the layout orientation is VERTICAL_WRAP and visibleRowCount <= 0; otherwise returns false.
boolean	getScrollableTracksViewportWidth ()           Returns true if this JList is displayed in a JViewport and the viewport is wider than the list's JList's preferred width, width; or if the layout orientation is HORIZONTAL_WRAP and visibleRowCount <= 0; 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 column (for horizontal scrolling).
int	getSelectedIndex ()           Returns the smallest first selected cell index; the selection when only a single item returns -1 if there is no selected in the list. item.
int[]	getSelectedIndices ()           Returns an array of all of the selected indices, indices in increasing order.
Object	getSelectedValue ()           Returns the value for the smallest first selected cell index; value, or null if the selected value when only a single item selection is selected in the list. empty.
Object	getSelectedValues ()           Returns an array of all the values for the selected values, in increasing order based on their indices in the list. cells.
Color	getSelectionBackground ()           Returns the background color used to draw the background of for selected items. cells.
Color	getSelectionForeground ()           Returns the color used to draw the selection foreground of selected items. color.
int	getSelectionMode ()           Returns the current selection mode for the list. whether single-item or multiple-item selections are allowed.
ListSelectionModel	getSelectionModel ()           Returns the value of the current selection model.
String	getToolTipText ( MouseEvent           Returns           Overrides JComponent's getToolTipText method in order to allow the tooltip text renderer's tips to be used for the given event. if it has text set.
ListUI	getUI ()           Returns the ListUI, the look and feel (L&F) object that renders this component.
String	getUIClassID ()           Returns "ListUI", the UIDefaults key suffix used to look up construct the name of the javax.swing.plaf.ListUI class that defines the look and feel for (L&F) class used to render this component.
boolean	getValueIsAdjusting ()           Returns the value of the selection data model's isAdjusting property.
int	getVisibleRowCount ()           Returns the value preferred number of the visibleRowCount property. visible rows.
Point	indexToLocation (int index)           Returns the origin of the specified item in the list's coordinate system. JList coordinates.
boolean	isSelectedIndex (int index)           Returns true if the specified index is selected, else false. selected.
boolean	isSelectionEmpty ()           Returns true if nothing is selected, else false. selected.
int	locationToIndex ( Point           Returns           Convert a point in JList coordinates to the cell closest index closest to of the given location in the list's coordinate system. cell at that location.
protected   String	paramString ()           Returns a String string representation of this JList.
void	removeListSelectionListener ( ListSelectionListener           Removes a selection listener from the list. 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           Sets the delegate that is that's used to paint each cell in the list.
void	setDragEnabled (boolean b)           Turns on or off           Sets the dragEnabled property, which must be true to enable automatic drag handling. handling (the first part of drag and drop) on this component.
void	setDropMode ( DropMode           Sets           Set the drop mode for this component.
void	setFixedCellHeight (int height)           Sets a fixed value to be used for the height of every cell in the list.
void	setFixedCellWidth (int width)           Sets a fixed value to be used for the width of every cell in the list.
void	setLayoutOrientation (int layoutOrientation)           Defines the way list cells are layed out.
void	setListData ( Object           Constructs a read-only ListModel from an array of objects, objects and calls then applies setModel with this model. to it.
void	setListData ( Vector           Constructs a read-only ListModel from a Vector and calls then applies setModel with this model. to it.
void	setModel ( ListModel           Sets the model that represents the contents or "value" of the list, notifies property change listeners, list and then clears the list's selection. list selection after notifying PropertyChangeListeners.
void	setPrototypeCellValue ( Object           Sets           Computes the prototypeCellValue property, and then (if the new value is non-null), computes the fixedCellWidth and fixedCellHeight properties by requesting configuring the cell renderer component cellRenderer to index equals zero for the given specified value (and index 0) from and then computing the cell renderer, and using that renderer component's preferred size.
void	setSelectedIndex (int index)           Selects a single cell.
void	setSelectedIndices (int[] indices)           Changes the selection to be the           Selects a set of indices specified by the given array. cells.
void	setSelectedValue ( Object  anObject, boolean shouldScroll)           Selects the specified object from the list.
void	setSelectionBackground ( Color           Sets the background color used to draw the background of for selected items, which cell renderers can use fill selected cells.
void	setSelectionForeground ( Color           Sets the foreground color used to draw the foreground of for selected items, which cell renderers can use to render text and graphics. cells.
void	setSelectionInterval (int anchor, int lead)           Selects the specified interval.
void	setSelectionMode (int selectionMode)           Sets the selection mode for the list.           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           Sets the ListUI, the look and feel (L&F) object that renders this component.
void	setValueIsAdjusting (boolean b)           Sets the selection model's valueIsAdjusting property.
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 visibleRowCount property, which has different meanings depending on the layout orientation: For a VERTICAL layout orientation, this sets the preferred number of rows to display without requiring scrolling; for other orientations, it affects the wrapping of cells.
void	setVisibleRowCount (int visibleRowCount)           Sets the preferred number of rows in the list that can be displayed without a scrollbar, as determined by the nearest JViewport ancestor, if any.
void	updateUI ()           Resets the ListUI UI property by setting it to with the value provided by from the current look and feel.

VERTICAL

public static final int VERTICAL

Indicates a vertical layout of cells, in a single column; the default layout. Indicates the default layout: one column of cells.

Since:

1.4

See Also:

setLayoutOrientation(int) , Constant Field Values

VERTICAL_WRAP

public static final int VERTICAL_WRAP

Indicates a "newspaper style" layout with the cells flowing vertically then horizontally.

Since:

1.4

See Also:

setLayoutOrientation(int) , Constant Field Values

HORIZONTAL_WRAP

public static final int HORIZONTAL_WRAP

Indicates a "newspaper style" layout with the cells flowing horizontally then vertically.

Since:

1.4

See Also:

setLayoutOrientation(int) , Constant Field Values

JList

public JList(ListModel dataModel)

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

This constructor registers the list with the ToolTipManager, allowing for tooltips to be provided by the cell renderers.

Parameters:

dataModel - the data model for the this list

Throws:

IllegalArgumentException - if the model dataModel is null

JList

public JList(Object[] listData)

Constructs a JList that displays the elements in the specified array. This constructor creates a read-only model for the given array, and then delegates to the constructor that takes a ListModel. This constructor just delegates to the ListModel constructor.

Attempts to pass a null value to this method results in undefined behavior and, most likely, exceptions. The created model references the given array directly. Attempts to modify the array after constructing the list results in undefined behavior.

Parameters:

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

JList

public JList(Vector<?> listData)

Constructs a JList that displays the elements in the specified Vector. This constructor creates a read-only model for the given Vector, and then delegates to the constructor that takes a ListModel. This constructor just delegates to the ListModel constructor.

Attempts to pass a null value to this method results in undefined behavior and, most likely, exceptions. The created model references the given Vector directly. Attempts to modify the Vector after constructing the list results in undefined behavior.

Parameters:

listData - the Vector to be loaded into the data model, non-null model

JList

public JList()

Constructs a JList with an empty, read-only, empty model.

getUI

public ListUI getUI()

Returns the ListUI, 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 ListUI, 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()

Resets the ListUI property by setting it to the value provided by the current look and feel. If the current cell renderer was installed by the developer (rather than the look and feel itself), this also causes the cell renderer and its children to be updated, by calling SwingUtilities.updateComponentTreeUI on it. Resets the UI property with the value from the current look and feel.

Overrides:

updateUI in class JComponent

See Also:

UIManager.getUI(javax.swing.JComponent) , SwingUtilities.updateComponentTreeUI(java.awt.Component)

getUIClassID

public String getUIClassID()

Returns "ListUI", the UIDefaults key suffix used to look up construct the name of the javax.swing.plaf.ListUI class that defines the look and feel for (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 "prototypical" cell value -- a value used to calculate a fixed width and height for cells. This can be null if there is no such value. 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)

Sets the prototypeCellValue property, and then (if the new value is non-null), computes the fixedCellWidth and fixedCellHeight properties by requesting the cell renderer component for the given value (and index 0) from the cell renderer, and using that component's preferred size. 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.

This method is useful when the list is too long to allow the ListUI 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, a so-called prototype. Note that we do set the fixedCellWidth and fixedCellHeight properties here but only a prototypeCellValue PropertyChangeEvent is fired.

While all three of the prototypeCellValue, fixedCellHeight, and fixedCellWidth properties may be modified by this method, PropertyChangeEvent notifications are only sent when the prototypeCellValue property changes.

To see an example which sets this property, see the class description 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) , Container.addPropertyChangeListener(java.beans.PropertyChangeListener)

getFixedCellWidth

public int getFixedCellWidth()

Returns the value of the fixedCellWidth property. 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 a fixed value to be used for the width of every cell in the list. If width is -1, cell widths are computed in the ListUI by applying getPreferredSize to the cell renderer cellRenderer component for each list element.

The default value of this property is -1.

This is a JavaBeans bound property.

Parameters:

width - the width to be used width, in pixels, for all cells in the this list

See Also:

setPrototypeCellValue(java.lang.Object) getPrototypeCellValue() , setFixedCellWidth(int) , Container.addPropertyChangeListener(java.beans.PropertyChangeListener)

getFixedCellHeight

public int getFixedCellHeight()

Returns the value of the fixedCellHeight property. 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 height, in pixels

See Also:

setFixedCellHeight(int)

setFixedCellHeight

public void setFixedCellHeight(int height)

Sets a fixed value to be used for the height of every cell in the list. If height is -1, cell heights are computed in the ListUI by applying getPreferredSize to the cell renderer 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 to be used height, in pixels, for for all cells in the this list

See Also:

setPrototypeCellValue(java.lang.Object) getPrototypeCellValue() , setFixedCellWidth(int) , Container.addPropertyChangeListener(java.beans.PropertyChangeListener)

getCellRenderer

public ListCellRenderer getCellRenderer()

Returns the object responsible for painting that renders the list items.

Returns:

the value of the cellRenderer property the ListCellRenderer

See Also:

setCellRenderer(javax.swing.ListCellRenderer)

setCellRenderer

public void setCellRenderer(ListCellRenderer cellRenderer)

Sets the delegate that is used to paint each cell in the list. The job of a cell renderer is discussed in detail in the class level documentation .

If the prototypeCellValue property is non-null, setting the cell renderer also causes the fixedCellWidth and fixedCellHeight properties to be re-calculated. 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 color used to draw the foreground of selected items. DefaultListCellRenderer uses this color to draw the foreground of items in the selected state, as do the renderers installed by most ListUI implementations. Returns the selection foreground color.

Returns:

the color to draw the foreground of selected items the Color object for the foreground property

See Also:

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

setSelectionForeground

public void setSelectionForeground(Color selectionForeground)

Sets the color used to draw the foreground of selected items, which cell renderers can use to render text and graphics. DefaultListCellRenderer uses this color to draw the foreground of items in the selected state, as do the renderers installed by most ListUI implementations. 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) , DefaultListCellRenderer

getSelectionBackground

public Color getSelectionBackground()

Returns the color used to draw the background of selected items. DefaultListCellRenderer uses this color to draw the background of items in the selected state, as do the renderers installed by most ListUI implementations. Returns the background color for selected cells.

Returns:

the color to draw Color used for the background of selected list items

See Also:

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

setSelectionBackground

public void setSelectionBackground(Color selectionBackground)

Sets the color used to draw the background of selected items, which cell renderers can use fill selected cells. DefaultListCellRenderer uses this color to fill the background of items in the selected state, as do the renderers installed by most ListUI implementations. 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) , DefaultListCellRenderer

getVisibleRowCount

public int getVisibleRowCount()

Returns the value of the visibleRowCount property. See the documentation for setVisibleRowCount(int) for details on how to interpret this value. Returns the preferred number of visible rows.

Returns:

the value of the visibleRowCount property. 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 visibleRowCount property, which has different meanings depending on the layout orientation: For a VERTICAL layout orientation, this sets the preferred number of rows to display without requiring scrolling; for other orientations, it affects the wrapping of cells. Sets the preferred number of rows in the list that can be displayed without a scrollbar, as determined by the nearest JViewport ancestor, if any. The value of this property only affects the value of the JList's preferredScrollableViewportSize.

In VERTICAL orientation:
Setting this property affects the return value of the getPreferredScrollableViewportSize() method, which is used to calculate the preferred size of an enclosing viewport. See that method's documentation for more details.

In HORIZONTAL_WRAP and VERTICAL_WRAP orientations:
This affects how cells are wrapped. See the documentation of setLayoutOrientation(int) for more details.

The default value of this property is 8.

Calling this method with a negative value results in the property being set to 0.

This is a JavaBeans bound property.

Parameters:

visibleRowCount - an integer specifying the preferred number of visible rows to display without requiring scrolling

See Also:

getVisibleRowCount() , getPreferredScrollableViewportSize() , setLayoutOrientation(int) , JComponent.getVisibleRect() , JViewport

getLayoutOrientation

public int getLayoutOrientation()

Returns the layout orientation property for the list: VERTICAL JList.VERTICAL if the layout is a single column of cells, VERTICAL_WRAP or JList.VERTICAL_WRAP if the layout is "newspaper style" with the content flowing vertically then horizontally, horizontally or HORIZONTAL_WRAP JList.HORIZONTAL_WRAP if the layout is "newspaper style" with the content flowing horizontally then vertically.

Returns:

the value of the layoutOrientation property

Since:

1.4

See Also:

setLayoutOrientation(int)

setLayoutOrientation

public void setLayoutOrientation(int layoutOrientation)

Defines the way list cells are layed out. Consider a JList with five cells. Cells four cells, this can be layed out in one of the following ways:

 VERTICAL: 0
 1
 2
 3
 4

 HORIZONTAL_WRAP: 0 1 2
 3 4

 VERTICAL_WRAP: 0 3
 1 4
 2
 
 0
 1
 2
 3
 

 0 1
 2 3
 

 0 2
 1 3
 

A description of these layouts follows: These correspond to the following values:

Value	Description
VERTICAL JList.VERTICAL	Cells are The cells should be layed out vertically in a single one column.
HORIZONTAL_WRAP JList.HORIZONTAL_WRAP	Cells are layed out horizontally, wrapping to a new row as necessary. If the visibleRowCount property is less than or equal to zero, wrapping is determined by the width of the list; otherwise wrapping is done in such a way as to ensure visibleRowCount rows in the list. The cells should be layed out horizontally, wrapping to a new row as necessary. The number of rows to use will either be defined by getVisibleRowCount if > 0, otherwise the number of rows will be determined by the width of the JList.
VERTICAL_WRAP JList.VERTICAL_WRAP	Cells are layed out vertically, wrapping to a new column as necessary. If the visibleRowCount property is less than or equal to zero, wrapping is determined by the height of the list; otherwise wrapping is done at visibleRowCount rows. The cells should be layed out vertically, wrapping to a new column as necessary. The number of rows to use will either be defined by getVisibleRowCount if > 0, otherwise the number of rows will be determined by the height of the JList.

The default value of this property is JList.VERTICAL.

The default value of this property is VERTICAL. This will throw an IllegalArgumentException if layoutOrientation is not one of JList.HORIZONTAL_WRAP or JList.VERTICAL or JList.VERTICAL_WRAP

Parameters:

layoutOrientation - the new layout orientation, one of: VERTICAL, HORIZONTAL_WRAP or VERTICAL_WRAP layoutOrientation - New orientation, one of JList.HORIZONTAL_WRAP, JList.VERTICAL or JList.VERTICAL_WRAP.

Throws:

IllegalArgumentException - if layoutOrientation isn't one of the allowable values

Since:

1.4

See Also:

getLayoutOrientation() , setVisibleRowCount(int) , getScrollableTracksViewportHeight() , getScrollableTracksViewportWidth()

getFirstVisibleIndex

public int getFirstVisibleIndex()

Returns the smallest list index that of the first visible cell. The cell considered to be "first" depends on the list's componentOrientation property. If the orientation is currently visible. In a left-to-right componentOrientation, horizontal left-to-right, then the first visible cell is found closest to in the list's upper-left corner. In right-to-left orientation, it If the orientation is found closest to horizontal right-to-left, then the first visible cell is in the list's upper-right corner. If nothing is visible or the list is empty, a -1 is returned. Note that the returned 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 largest list index that is currently visible. If nothing is visible or the list is empty, -1 is returned. Returns the index of the last visible cell. The cell considered to be "last" depends on the list's componentOrientation property. If the orientation is horizontal left-to-right, then the last visible cell is in the JList's lower-right corner. If the orientation is horizontal right-to-left, then the last visible cell is in the JList's lower-left corner. If nothing is visible or the list is empty, a -1 is returned. Note that the returned cell may only be partially visible.

Returns:

the index of the last visible cell

See Also:

getFirstVisibleIndex() , JComponent.getVisibleRect()

ensureIndexIsVisible

public void ensureIndexIsVisible(int index)

Scrolls the list within an enclosing viewport to make the specified cell completely visible. This calls scrollRectToVisible with the bounds of the specified cell. For Note, for this method to work, the JList must be displayed within a JViewport.

If the given index is outside the list's range of cells, this method results in nothing.

Parameters:

index - the index of the cell to make visible

See Also:

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

setDragEnabled

public void setDragEnabled(boolean b)

Turns on or off automatic drag handling. In order to enable automatic drag handling, this property should be set to true, and the list's TransferHandler needs to be non-null. Sets the dragEnabled property, which must be true to enable automatic drag handling (the first part of drag and drop) on this component. The transferHandler property needs to be set to a non-null value for the drag to do anything. The default value of the dragEnabled property is false.

The job of honoring this property, and recognizing a user drag gesture, lies with the look and feel implementation, and in particular, the list's ListUI. When automatic drag handling is enabled, most look and feels (including those that subclass BasicLookAndFeel) begin a drag and drop drag-and-drop operation whenever the user presses the mouse button over an item and then moves the mouse a few pixels. Setting this property to true can therefore have a subtle effect on how selections behave.

If a look and feel is used that ignores this property, you can still begin a drag and drop operation by calling exportAsDrag on the list's TransferHandler. Some look and feels might not support automatic drag and drop; they will ignore this property. You can work around such look and feels by modifying the component to directly call the exportAsDrag method of a TransferHandler.

Parameters:

b - whether or not to enable automatic drag handling b - the value to set the dragEnabled property to

Throws:

HeadlessException - if b is true and GraphicsEnvironment.isHeadless() returns true

Since:

1.4

See Also:

GraphicsEnvironment.isHeadless() , getDragEnabled() , JComponent.setTransferHandler(javax.swing.TransferHandler) , TransferHandler

getDragEnabled

public boolean getDragEnabled()

Returns whether or not automatic drag handling is enabled. Gets the dragEnabled property.

Returns:

the value of the dragEnabled property

Since:

1.4

See Also:

setDragEnabled(boolean)

setDropMode

public final void setDropMode(DropMode dropMode)

Sets Set the drop mode for this component. For backward compatibility, the default for this property is DropMode.USE_SELECTION. Usage of one of the other modes is recommended, however, for an improved user experience. DropMode.ON, for instance, offers similar behavior of showing items as selected, but does so without affecting the actual selection in the list.

JList supports the following drop modes:

• DropMode.USE_SELECTION
• DropMode.ON
• DropMode.INSERT
• DropMode.ON_OR_INSERT

The drop mode is only meaningful if this component has a TransferHandler that accepts drops.

Parameters:

dropMode - the drop mode to use

Throws:

IllegalArgumentException - if the drop mode is unsupported or null

Since:

1.6

See Also:

getDropMode() , getDropLocation() , JComponent.setTransferHandler(javax.swing.TransferHandler) , TransferHandler

getDropMode

public final DropMode getDropMode()

Returns the drop mode for this component.

Returns:

the drop mode for this component

Since:

1.6

See Also:

setDropMode(javax.swing.DropMode)

getDropLocation

public final JList.DropLocation getDropLocation()

Returns the location that this component should visually indicate as the drop location during a DnD operation over the component, or component. This will be null if there is no DnD operation over the component or if the component's TransferHandler has indicated that it cannot accept the current transfer (and has not specified that the drop location is to currently be shown. indicated anyway).

This method is not meant for querying the drop location from a TransferHandler, TransferHandler as the drop location is only set after the TransferHandler's canImport has or shouldIndicateAnyway methods have returned and has allowed for the location to be shown. true.

When this property changes, a property change event with name "dropLocation" is fired by the component.

By default, responsibility for listening for changes to this property and indicating the drop location visually lies with the list's ListUI, which may paint it directly and/or install a cell renderer to do so. Developers wishing to implement custom drop location painting and/or replace the default cell renderer, may need to honor this property.

Returns:

the drop location

Since:

1.6

See Also:

setDropMode(javax.swing.DropMode) , TransferHandler.canImport(TransferHandler.TransferSupport) TransferHandler.TransferInfo , TransferHandler.canImport(TransferHandler.TransferInfo) , TransferHandler#shouldIndicateAnyway(TransferHandler.TransferInfo)

getNextMatch

public int getNextMatch(String prefix,
                        int startIndex,
                        Position.Bias bias)

Returns the next list element whose toString value that starts with the given a prefix.

Parameters:

prefix - the string to test for a match

startIndex - the index for starting the search

bias - the search direction, either Position.Bias.Forward or Position.Bias.Backward.

Returns:

the index of the next list element that starts with the prefix; otherwise -1

Throws:

IllegalArgumentException - if prefix is null or startIndex is out of bounds

Since:

1.4

getToolTipText

public String getToolTipText(MouseEvent event)

Returns the tooltip text to be used for the given event. This overrides JComponent's getToolTipText to first check the cell renderer component for the cell over which the event occurred, returning its tooltip text, if any. This implementation allows you to specify tooltip text on the cell level, by using setToolTipText on your cell renderer component. Overrides JComponent's getToolTipText method in order to allow the renderer's tips to be used if it has text set.

Note: For JList to properly display the tooltips of its renderers in this manner, JList must be a registered component with the ToolTipManager. This registration is done automatically in the constructor. However, constructor, but if at a later point JList is unregistered, by way of a call to setToolTipText(null), told setToolTipText(null) it will unregister the list component, and no tips from the renderers will no longer display. display anymore.

Overrides:

getToolTipText in class JComponent

Parameters:

event - the MouseEvent to fetch the tooltip text for

See Also:

JComponent.setToolTipText(java.lang.String) JComponent.getToolTipText() , JComponent.getToolTipText()

locationToIndex

public int locationToIndex(Point location)

Returns the cell index closest to the given location in the list's coordinate system. To determine if the cell actually contains the specified location, compare the point against the cell's bounds, as provided by getCellBounds. This method returns -1 if the model is empty Convert a point in JList coordinates to the closest index of the cell at that location. To determine if the cell actually contains the specified location use a combination of this method and getCellBounds. Returns -1 if the model is empty.

This is a cover method that delegates to the method of the same name in the list's ListUI. It returns -1 if the list has no ListUI.

Parameters:

location - the coordinates of the point cell, relative to JList

Returns:

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

indexToLocation

public Point indexToLocation(int index)

Returns the origin of the specified item in the list's coordinate system. This method returns JList coordinates. Returns null if the index isn't valid.

This is a cover method that delegates to the method of the same name in the list's ListUI. It returns null if the list has no ListUI.

Parameters:

index - the index of the JList cell index

Returns:

the origin of the cell, or null index'th cell

getCellBounds

public Rectangle getCellBounds(int index0,
                               int index1)

Returns the bounding rectangle, in the list's coordinate system, for the range of cells specified by the two indices. These indices can be supplied in any order. Returns the bounds of the specified range of items in JList coordinates. Returns null if index isn't valid.

If the smaller index is outside the list's range of cells, this method returns null. If the smaller index is valid, but the larger index is outside the list's range, the bounds of just the first index is returned. Otherwise, the bounds of the valid range is returned.

This is a cover method that delegates to the method of the same name in the list's ListUI. It returns null if the list has no ListUI.

Parameters:

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

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

Returns:

the bounding rectangle for the range of cells, or null 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, notifies property change listeners, list and then clears the list's selection. 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() , clearSelection()

setListData

public void setListData(Object[] listData)

Constructs a read-only ListModel from an array of objects, objects and calls then applies setModel with this model. to it.

Attempts to pass a null value to this method results in undefined behavior and, most likely, exceptions. The created model references the given array directly. Attempts to modify the array after invoking this method results in undefined behavior.

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 read-only ListModel from a Vector and calls then applies setModel with this model. to it.

Attempts to pass a null value to this method results in undefined behavior and, most likely, exceptions. The created model references the given Vector directly. Attempts to modify the Vector after invoking this method results in undefined behavior.

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; called during construction DefaultListSelectionModel. This method is used by the constructor to initialize the list's selection model selectionModel property.

Returns:

a DefaultListSelecitonModel, used to initialize the list's selection model property during construction the ListSelectionModel used by this JList.

See Also:

setSelectionModel(javax.swing.ListSelectionModel) , DefaultListSelectionModel

getSelectionModel

public ListSelectionModel getSelectionModel()

Returns the current selection model. The selection model maintains the selection state of the list. See the class level documentation for more details. 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 maintains the list's implements list selections

See Also:

setSelectionModel(javax.swing.ListSelectionModel) , ListSelectionModel

fireSelectionValueChanged

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

Notifies ListSelectionListeners added directly to the list of selection changes made to the selection model. JList listens for changes made to the selection in the selection model, and forwards notification to listeners added to the list directly, by calling this method. 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.

This method constructs a ListSelectionEvent with this list as the source, and the specified arguments, and sends it to the registered ListSelectionListeners.

Parameters:

firstIndex - the first selected index in the range, <= lastIndex

lastIndex - the last selected index in the range, >= firstIndex

isAdjusting - whether or not this is one in a series of multiple events, where changes are still being made isAdjusting - true if multiple changes are being made

See Also:

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

addListSelectionListener

public void addListSelectionListener(ListSelectionListener listener)

Adds a listener to the list, to be notified each time a change to the selection occurs; the preferred way of listening for selection state changes. JList takes care of listening for selection state changes in the selection model, and notifies the given listener of each change. ListSelectionEvents sent to the listener have a source property set to this list. 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() , getListSelectionListeners()

removeListSelectionListener

public void removeListSelectionListener(ListSelectionListener listener)

Removes a selection listener from the list. 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()

getListSelectionListeners

public ListSelectionListener[] getListSelectionListeners()

Returns an array of all the ListSelectionListeners added to this JList by way of addListSelectionListener. with addListSelectionListener().

Returns:

all of the ListSelectionListeners on this list, added or an empty array if no listeners have been added

Since:

1.4

See Also:

addListSelectionListener(javax.swing.event.ListSelectionListener)

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)

Sets the selection mode for the list. This is a cover method that sets the selection mode directly on the selection model.

The following list describes the accepted selection modes: Determines whether single-item or multiple-item selections are allowed. The following selectionMode values are allowed:

• ListSelectionModel.SINGLE_SELECTION - Only one list index can be selected at a time. In this mode, mode the setSelectionInterval and addSelectionInterval methods are equivalent, both replacing and only the current selection with the second index represented by the second argument (the "lead"). is used.
• ListSelectionModel.SINGLE_INTERVAL_SELECTION - Only one One contiguous index interval can be selected at a time. In this mode, addSelectionInterval behaves like mode setSelectionInterval (replacing the current selection}, unless the given interval is immediately adjacent to or overlaps the existing selection, and can be used to grow the selection. addSelectionInterval are equivalent.
• ListSelectionModel.MULTIPLE_INTERVAL_SELECTION - In this mode, there's no restriction on what can be selected. This mode is the default.

Parameters:

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

Throws:

IllegalArgumentException - if the selection mode isn't one of those allowed

See Also:

getSelectionMode()

getSelectionMode

public int getSelectionMode()

Returns the current selection mode for the list. This is a cover method that delegates to the method of the same name on the list's selection model. Returns whether single-item or multiple-item selections are allowed.

Returns:

the current selection mode the value of the selectionMode property

See Also:

setSelectionMode(int)

getAnchorSelectionIndex

public int getAnchorSelectionIndex()

Returns the anchor selection index. This is a cover method that delegates to the method of the same name on the list's selection model. 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 anchor selection index 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 lead selection index. This is a cover method that delegates to the method of the same name on the list's selection model. 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 lead selection index 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, or -1 if the selection is empty. index. This is a cover convenience method that just delegates to the method of the same name on the list's selection model. selectionModel.

Returns:

the smallest selected cell index, or -1 index

See Also:

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

getMaxSelectionIndex

public int getMaxSelectionIndex()

Returns the largest selected cell index, or -1 if the selection is empty. index. This is a cover convenience method that just delegates to the method of the same name on the list's selection model. 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, else false. selected. This is a cover convenience method that just delegates to the method of the same name on the list's selection model. selectionModel.

Parameters:

index - index to be queried for selection state

Returns:

true if the specified index is selected, else false selected

See Also:

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

isSelectionEmpty

public boolean isSelectionEmpty()

Returns true if nothing is selected, else false. selected. This is a cover convenience method that just delegates to the method of the same name on the list's selection model. selectionModel.

Returns:

true if nothing is selected, else false selected

See Also:

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

clearSelection

public void clearSelection()

Clears the selection; selection - after calling this method, method isSelectionEmpty will return true. This is a cover convenience method that just delegates to the method of the same name on the list's selection model. selectionModel.

See Also:

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

setSelectionInterval

public void setSelectionInterval(int anchor,
                                 int lead)

Selects the specified interval. Both anchor and lead indices are included. anchor doesn't have to be less than or equal to lead. This is a cover method that delegates to the method of the same name on the list's selection model. Both the anchor and lead indices are included. It's not necessary for anchor to be less than lead. This is a convenience method that just delegates to the selectionModel. The DefaultListSelectionModel implementation will do nothing if either anchor or lead are -1. If anchor or lead are less than -1, IndexOutOfBoundsException is thrown.

Refer to the documentation of the selection model class being used for details on how values less than 0 are handled.

Parameters:

anchor - the first index to select

lead - the last index to select

Throws:

IndexOutOfBoundsException - if either anchor or lead are less than -1

See Also:

ListSelectionModel.setSelectionInterval(int, int) , DefaultListSelectionModel.setSelectionInterval(int, int) , createSelectionModel() , 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. anchor doesn't have to be less than or equal to lead. This is a cover method that delegates to the method of the same name on the list's selection model. It's not necessary for anchor to be less than lead. This is a convenience method that just delegates to the selectionModel. The DefaultListSelectionModel implementation will do nothing if either anchor or lead are -1. If anchor or lead are less than -1, IndexOutOfBoundsException is thrown.

Refer to the documentation of the selection model class being used for details on how values less than 0 are handled.

Parameters:

anchor - the first index to add to the selection

lead - the last index to add to the selection

Throws:

IndexOutOfBoundsException - if either anchor or lead are less than -1

See Also:

ListSelectionModel.addSelectionInterval(int, int) , DefaultListSelectionModel.addSelectionInterval(int, int) , createSelectionModel() , 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 index0 and index1 indices are removed. index0 doesn't have to be less than or equal to index1. This is a cover method that delegates to the method of the same name on the list's selection model. It's not necessary for index0 to be less than index1. This is a convenience method that just delegates to the selectionModel. The DefaultListSelectionModel implementation will do nothing if either index0 or index1 are -1. If index0 or index1 are less than -1, IndexOutOfBoundsException is thrown.

Refer to the documentation of the selection model class being used for details on how values less than 0 are handled.

Parameters:

index0 - the first index to remove from the selection

index1 - the last index to remove from the selection

Throws:

IndexOutOfBoundsException - if either index0 or index1 are less than -1

See Also:

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

setValueIsAdjusting

public void setValueIsAdjusting(boolean b)

Sets the selection model's valueIsAdjusting property. When true, upcoming changes to selection should be considered part of a single change. This property is used internally and developers typically need not call this method. For example, when the model is being updated in response to a user drag, the value of the property is set to true when the drag is initiated and set to false when the drag is finished. This allows listeners to update only when a change has been finalized, rather than handling all of the intermediate values. 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).

You may want to use this directly if making a series of changes that should be considered part of a single change.

This is a cover method that delegates to the method of the same name on the list's selection model. See the documentation for ListSelectionModel.setValueIsAdjusting(boolean) for more details.

Parameters:

b - the new boolean value for the property value

See Also:

ListSelectionModel.setValueIsAdjusting(boolean) , ListSelectionEvent.getValueIsAdjusting() , getValueIsAdjusting()

getValueIsAdjusting

public boolean getValueIsAdjusting()

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

This is a cover method that delegates to the method of the same name on the list's selection model.

Returns:

the value of the selection model's isAdjusting property. true if multiple selection-changes are occurring, as when the mouse is being dragged over the list

See Also:

setValueIsAdjusting(boolean) ListSelectionModel.getValueIsAdjusting() , ListSelectionModel.getValueIsAdjusting()

getSelectedIndices

public int[] getSelectedIndices()

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

Returns:

all of the selected indices, in increasing order, or an empty array if nothing is selected order

See Also:

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

setSelectedIndex

public void setSelectedIndex(int index)

Selects a single cell. Does nothing if the given index is greater than or equal to the model size. This is a convenience method that uses setSelectionInterval on the selection model. Refer to the documentation for the selection model class being used for details on how values less than 0 are handled.

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)

Changes the selection to be the set of indices specified by the given array. Indices greater than or equal to the model size are ignored. This is a convenience method that clears the selection and then uses addSelectionInterval on the selection model to add the indices. Refer to the documentation of the selection model class being used for details on how values less than 0 are handled. Selects a set of cells.

Parameters:

indices - an array of the indices of the cells to select, non-null select

Throws:

NullPointerException - if the given array is null

See Also:

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

getSelectedValues

public Object[] getSelectedValues()

Returns an array of all the selected values, in increasing order based on their indices in the list. Returns an array of the values for the selected cells. The returned values are sorted in increasing index order.

Returns:

the selected values, values or an empty array list if nothing is selected

See Also:

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

getSelectedIndex

public int getSelectedIndex()

Returns the smallest selected cell index; the selection when only a single item is selected in the list. When multiple items are selected, it is simply the smallest selected index. Returns -1 if there is no selection. Returns the first selected index; returns -1 if there is no selected item.

This method is a cover that delegates to getMinSelectionIndex.

Returns:

the smallest selected cell index the value of getMinSelectionIndex

See Also:

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

getSelectedValue

public Object getSelectedValue()

Returns the value for the smallest selected cell index; the selected value when only a single item is selected in the list. When multiple items are selected, it is simply the value for the smallest selected index. Returns null if there is no selection. Returns the first selected value, or null if the selection is empty.

This is a convenience method that simply returns the model value for getMinSelectionIndex.

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 viewport needed to display visibleRowCount rows. The value returned by this method depends on the layout orientation: 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.

If the layout orientation is not VERTICAL, than this will return the value from getPreferredSize. The current ListUI is expected to override getPreferredSize to return an appropriate value.

VERTICAL:
This is trivial if both fixedCellWidth and fixedCellHeight have been set (either explicitly or by specifying a prototype cell value). The width is simply the fixedCellWidth plus the list's horizontal insets. The height is the fixedCellHeight multiplied by the visibleRowCount, plus the list's vertical insets.

If either fixedCellWidth or fixedCellHeight haven't been specified, heuristics are used. If the model is empty, the width is the fixedCellWidth, if greater than 0, or a hard-coded value of 256. The height is the fixedCellHeight multiplied by visibleRowCount, if fixedCellHeight is greater than 0, otherwise it is a hard-coded value of 16 multiplied by visibleRowCount.

If the model isn't empty, the width is the preferred size's width, typically the width of the widest list element. The height is the fixedCellHeight multiplied by the visibleRowCount, plus the list's vertical insets.

VERTICAL_WRAP or HORIZONTAL_WRAP:
This method simply returns the value from getPreferredSize. The list's ListUI is expected to override getPreferredSize to return an appropriate value.

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 column (for horizontal scrolling).

For horizontal scrolling, scrolling if the layout list is layed out vertically (the orientation is VERTICAL, then VERTICAL) than the list's lists font size or 1 is returned (or 1 if the font is null). null is used.

Specified by:

getScrollableUnitIncrement in interface Scrollable

Parameters:

visibleRect - the view area visible within the viewport rectangle

orientation - SwingConstants.HORIZONTAL HORIZONTAL or SwingConstants.VERTICAL VERTICAL

direction - less or equal to zero to scroll up/back, greater than zero for down/forward direction - if <= 0, then scroll UP; if > 0, then scroll DOWN

Returns:

the "unit" increment for scrolling in the specified direction; always positive 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 or SwingConstants.HORIZONTAL SwingConstants.VERTICAL, SwingConstants.HORIZONTAL.

See Also:

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

getScrollableBlockIncrement

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

Returns the distance to scroll to expose the next or previous block.

For vertical scrolling, the following rules are used: For vertical scrolling we are using the follows rules:

• if scrolling down, returns down (direction is greater than 0), the distance to scroll so that the last visible element becomes should become the first completely visible element
• if scrolling up, returns the distance to scroll so that the first visible element becomes should become the last completely visible element
• returns visibleRect.height if the list is empty

For horizontal scrolling, when scrolling if the layout list is layed out horizontally (the orientation is either VERTICAL_WRAP or HORIZONTAL_WRAP: HORIZONTAL_WRAP):

• if scrolling right, returns the distance to scroll so that the last visible element becomes the first completely visible element
• if scrolling left, returns the distance to scroll so that the first visible element becomes the last completely visible element
• returns visibleRect.width if the list is empty

if scrolling right (direction is greater than 0), the last visible element should become the first completely visible element

if scrolling left, the first visible element should become the last completely visible element

visibleRect.width if the list is empty

For horizontal scrolling and VERTICAL orientation, returns visibleRect.width. Return visibleRect.width if the list is layed out vertically.

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

Specified by:

getScrollableBlockIncrement in interface Scrollable

Parameters:

visibleRect - the view area visible within the viewport rectangle

orientation - SwingConstants.HORIZONTAL HORIZONTAL or SwingConstants.VERTICAL VERTICAL

direction - less or equal to zero to scroll up/back, greater than zero for down/forward direction - if <= 0, then scroll UP; if > 0, then scroll DOWN

Returns:

the "block" increment for scrolling in the specified direction; always positive the block increment amount.

Throws:

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

See Also:

getScrollableUnitIncrement(java.awt.Rectangle, int, int) Scrollable.getScrollableUnitIncrement(java.awt.Rectangle, int, int) , Scrollable.getScrollableBlockIncrement(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 the list's JList's preferred width, width; or if the layout orientation is HORIZONTAL_WRAP and visibleRowCount <= 0; otherwise returns false.

If false, then don't track the viewport's width. This allows horizontal scrolling if the JViewport visible row count is itself embedded in a JScrollPane.

<= 0; 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:

whether or not an enclosing viewport should force the list's width to match its own 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 the list's JList's preferred height, or if the layout orientation is VERTICAL_WRAP and visibleRowCount <= 0; otherwise returns false.

If false, then don't track the viewport's height. This allows vertical scrolling if the JViewport number of visible rows is itself embedded in a JScrollPane.

<= 0; 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:

whether or not an enclosing viewport should force the list's height to match its own true if viewport is taller than Jlist's preferred height, otherwise false

See Also:

Scrollable.getScrollableTracksViewportHeight()

paramString

protected String paramString()

Returns a String 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 string may vary between implementations. The returned String string may be empty, empty but may not be null.

Overrides:

paramString in class JComponent

Returns:

a String string representation of this JList.

getAccessibleContext

public AccessibleContext getAccessibleContext()

Gets the AccessibleContext associated with this JList. For JList, 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