E
- the type of the elements of this listImageObserver
, MenuContainer
, Serializable
, Accessible
, Scrollable
@JavaBean(defaultProperty="UI", description="A component which allows for the selection of one or more objects from a list.") public class JList<E> extends JComponent implements Scrollable, Accessible
ListModel
, maintains the contents of the list. It's easy to display an array or Vector of objects, using the 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<String> myList = new JList<String>(data);
// Create a JList that displays the superclasses of JList.class, by
// creating it with a Vector populated with this data
Vector<Class<?>> superClasses = new Vector<Class<?>>();
Class<JList> rootClass = javax.swing.JList.class;
for(Class<?> cls = rootClass; cls != null; cls = cls.getSuperclass()) {
superClasses.addElement(cls);
}
JList<Class<?>> myList = new JList<Class<?>>(superClasses);
// The automatically created model is stored in JList's "model"
// property, which you can retrieve
ListModel<Class<?>> model = myList.getModel();
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.ListDataListener
s 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.
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
:
// This list model has about 2^16 elements. Enjoy scrolling.
ListModel<String> bigData = new AbstractListModel<String>() {
public int getSize() { return Short.MAX_VALUE; }
public String getElementAt(int index) { return "Index " + index; }
};
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.ListSelectionListener
s 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 ListSelectionListener
s directly to the JList
. JList
then takes care of listening to 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
. You can substitute your own renderer using code like this:
// Display an icon and a string for each object in the list.
class MyCellRenderer extends JLabel implements ListCellRenderer<Object> {
static final ImageIcon longIcon = new ImageIcon("long.gif");
static final 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<String> bigDataList = new JList<String>(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
doesn't implement scrolling directly. To create a list that scrolls, make it the viewport view of a JScrollPane
. For example:
JScrollPane scrollPane = new JScrollPane(myList); // Or in two steps: JScrollPane scrollPane = new JScrollPane(); scrollPane.getViewport().setView(myList);
JList
doesn't provide any special handling of double or triple (or N) mouse clicks, but it's easy to add a MouseListener
if you wish to take action on these events. Use the locationToIndex
method to determine what cell was clicked. For example:
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 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 has been added to the java.beans
package. Please see XMLEncoder
.
See How to Use Lists in The Java Tutorial for further documentation.
Modifier and Type | Class | Description |
---|---|---|
protected class |
JList.AccessibleJList |
This class implements accessibility support for the JList class. |
static final class |
JList.DropLocation |
A subclass of TransferHandler.DropLocation representing a drop location for a JList . |
JComponent.AccessibleJComponent
Container.AccessibleAWTContainer
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
Modifier and Type | Field | Description |
---|---|---|
static final int |
HORIZONTAL_WRAP |
Indicates a "newspaper style" layout with cells flowing horizontally then vertically. |
static final int |
VERTICAL |
Indicates a vertical layout of cells, in a single column; the default layout. |
static final int |
VERTICAL_WRAP |
Indicates a "newspaper style" layout with cells flowing vertically then horizontally. |
listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW
accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
Constructor | Description |
---|---|
JList() |
Constructs a JList with an empty, read-only, model. |
JList |
Constructs a JList that displays the elements in the specified array. |
JList |
Constructs a JList that displays the elements in the specified Vector . |
JList |
Constructs a JList that displays elements from the specified, non-null , model. |
Modifier and Type | Method | Description |
---|---|---|
void |
addListSelectionListener |
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. |
void |
addSelectionInterval |
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 ; called during construction to initialize the list's selection model property. |
void |
ensureIndexIsVisible |
Scrolls the list within an enclosing viewport to make the specified cell completely visible. |
protected void |
fireSelectionValueChanged |
Notifies ListSelectionListener s added directly to the list of selection changes made to the selection model. |
AccessibleContext |
getAccessibleContext() |
Gets the AccessibleContext associated with this JList . |
int |
getAnchorSelectionIndex() |
Returns the anchor selection index. |
Rectangle |
getCellBounds |
Returns the bounding rectangle, in the list's coordinate system, for the range of cells specified by the two indices. |
ListCellRenderer |
getCellRenderer() |
Returns the object responsible for painting list items. |
boolean |
getDragEnabled() |
Returns whether or not automatic drag handling is enabled. |
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 null if no location is to currently be shown. |
final DropMode |
getDropMode() |
Returns the drop mode for this component. |
int |
getFirstVisibleIndex() |
Returns the smallest list index that is currently visible. |
int |
getFixedCellHeight() |
Returns the value of the fixedCellHeight property. |
int |
getFixedCellWidth() |
Returns the value of the fixedCellWidth property. |
int |
getLastVisibleIndex() |
Returns the largest list index that is currently visible. |
int |
getLayoutOrientation() |
Returns the layout orientation property for the list: VERTICAL if the layout is a single column of cells, VERTICAL_WRAP if the layout is "newspaper style" with the content flowing vertically then horizontally, or HORIZONTAL_WRAP if the layout is "newspaper style" with the content flowing horizontally then vertically. |
int |
getLeadSelectionIndex() |
Returns the lead selection index. |
ListSelectionListener[] |
getListSelectionListeners() |
Returns an array of all the ListSelectionListener s added to this JList by way of addListSelectionListener . |
int |
getMaxSelectionIndex() |
Returns the largest selected cell index, or -1 if the selection is empty. |
int |
getMinSelectionIndex() |
Returns the smallest selected cell index, or -1 if the selection is empty. |
ListModel |
getModel() |
Returns the data model that holds the list of items displayed by the JList component. |
int |
getNextMatch |
Returns the next list element whose toString value starts with the given prefix. |
Dimension |
getPreferredScrollableViewportSize() |
Computes the size of viewport needed to display visibleRowCount rows. |
E |
getPrototypeCellValue() |
Returns the "prototypical" cell value -- a value used to calculate a fixed width and height for cells. |
int |
getScrollableBlockIncrement |
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 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 preferred width, or if the layout orientation is HORIZONTAL_WRAP and visibleRowCount <= 0 ; otherwise returns false . |
int |
getScrollableUnitIncrement |
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 selected cell index; the selection when only a single item is selected in the list. |
int[] |
getSelectedIndices() |
Returns an array of all of the selected indices, in increasing order. |
E |
getSelectedValue() |
Returns the value for the smallest selected cell index; the selected value when only a single item is selected in the list. |
Object[] |
getSelectedValues() |
Deprecated. |
List |
getSelectedValuesList() |
Returns a list of all the selected items, in increasing order based on their indices in the list. |
Color |
getSelectionBackground() |
Returns the color used to draw the background of selected items. |
Color |
getSelectionForeground() |
Returns the color used to draw the foreground of selected items. |
int |
getSelectionMode() |
Returns the current selection mode for the list. |
ListSelectionModel |
getSelectionModel() |
Returns the current selection model. |
String |
getToolTipText |
Returns the tooltip text to be used for the given event. |
ListUI |
getUI() |
Returns the ListUI , the look and feel object that renders this component. |
String |
getUIClassID() |
Returns "ListUI" , the UIDefaults key used to look up the name of the javax.swing.plaf.ListUI class that defines the look and feel for this component. |
boolean |
getValueIsAdjusting() |
Returns the value of the selection model's isAdjusting property. |
int |
getVisibleRowCount() |
Returns the value of the visibleRowCount property. |
Point |
indexToLocation |
Returns the origin of the specified item in the list's coordinate system. |
boolean |
isSelectedIndex |
Returns true if the specified index is selected, else false . |
boolean |
isSelectionEmpty() |
Returns true if nothing is selected, else false . |
int |
locationToIndex |
Returns the cell index closest to the given location in the list's coordinate system. |
protected String |
paramString() |
Returns a String representation of this JList . |
void |
removeListSelectionListener |
Removes a selection listener from the list. |
void |
removeSelectionInterval |
Sets the selection to be the set difference of the specified interval and the current selection. |
void |
setCellRenderer |
Sets the delegate that is used to paint each cell in the list. |
void |
setDragEnabled |
Turns on or off automatic drag handling. |
final void |
setDropMode |
Sets the drop mode for this component. |
void |
setFixedCellHeight |
Sets a fixed value to be used for the height of every cell in the list. |
void |
setFixedCellWidth |
Sets a fixed value to be used for the width of every cell in the list. |
void |
setLayoutOrientation |
Defines the way list cells are laid out. |
void |
setListData |
Constructs a read-only ListModel from an array of items, and calls setModel with this model. |
void |
setListData |
Constructs a read-only ListModel from a Vector and calls setModel with this model. |
void |
setModel |
Sets the model that represents the contents or "value" of the list, notifies property change listeners, and then clears the list's selection. |
void |
setPrototypeCellValue |
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. |
void |
setSelectedIndex |
Selects a single cell. |
void |
setSelectedIndices |
Changes the selection to be the set of indices specified by the given array. |
void |
setSelectedValue |
Selects the specified object from the list. |
void |
setSelectionBackground |
Sets the color used to draw the background of selected items, which cell renderers can use fill selected cells. |
void |
setSelectionForeground |
Sets the color used to draw the foreground of selected items, which cell renderers can use to render text and graphics. |
void |
setSelectionInterval |
Selects the specified interval. |
void |
setSelectionMode |
Sets the selection mode for the list. |
void |
setSelectionModel |
Sets the selectionModel for the list to a non-null ListSelectionModel implementation. |
void |
setUI |
Sets the ListUI , the look and feel object that renders this component. |
void |
setValueIsAdjusting |
Sets the selection model's valueIsAdjusting property. |
void |
setVisibleRowCount |
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 |
updateUI() |
Resets the ListUI property by setting it to the value provided by the current look and feel. |
addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, hide, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingForPrint, isPaintingOrigin, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintBorder, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyEvent, processMouseEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setEnabled, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, update
add, add, add, add, add, addContainerListener, addImpl, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, getMousePosition, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setLayout, transferFocusDownCycle, validate, validateTree
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, createVolatileImage, createVolatileImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setMixingCutoutShape, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle
public static final int VERTICAL
public static final int VERTICAL_WRAP
public static final int HORIZONTAL_WRAP
public JList(ListModel<E> dataModel)
JList
that displays elements from the specified, 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.
dataModel
- the model for the listIllegalArgumentException
- if the model is null
public JList(E[] listData)
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
. 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.
listData
- the array of Objects to be loaded into the data model, non-null
public JList(Vector<? extends E> listData)
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
. 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.
listData
- the Vector
to be loaded into the data model, non-null
public JList()
JList
with an empty, read-only, model.public ListUI getUI()
ListUI
, the look and feel object that renders this component.getUI
in class JComponent
ListUI
object that renders this component@BeanProperty(hidden=true, visualUpdate=true, description="The UI object that implements the Component\'s LookAndFeel.") public void setUI(ListUI ui)
ListUI
, the look and feel object that renders this component.ui
- the ListUI
objectpublic void updateUI()
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.updateUI
in class JComponent
@BeanProperty(bound=false) public String getUIClassID()
"ListUI"
, the UIDefaults
key used to look up the name of the javax.swing.plaf.ListUI
class that defines the look and feel for this component.getUIClassID
in class JComponent
public E getPrototypeCellValue()
null
if there is no such value.prototypeCellValue
property@BeanProperty(visualUpdate=true, description="The cell prototype value, used to compute cell width and height.") public void setPrototypeCellValue(E prototypeCellValue)
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. 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.
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 above.
The default value of this property is null
.
This is a JavaBeans bound property.
prototypeCellValue
- the value on which to base fixedCellWidth
and fixedCellHeight
public int getFixedCellWidth()
fixedCellWidth
property.@BeanProperty(visualUpdate=true, description="Defines a fixed cell width when greater than zero.") public void setFixedCellWidth(int width)
width
is -1, cell widths are computed in the ListUI
by applying getPreferredSize
to the cell renderer component for each list element. The default value of this property is -1
.
This is a JavaBeans bound property.
width
- the width to be used for all cells in the listpublic int getFixedCellHeight()
fixedCellHeight
property.@BeanProperty(visualUpdate=true, description="Defines a fixed cell height when greater than zero.") public void setFixedCellHeight(int height)
height
is -1, cell heights are computed in the ListUI
by applying getPreferredSize
to the cell renderer component for each list element. The default value of this property is -1
.
This is a JavaBeans bound property.
height
- the height to be used for all cells in the listpublic ListCellRenderer<? super E> getCellRenderer()
cellRenderer
property@BeanProperty(visualUpdate=true, description="The component used to draw the cells.") public void setCellRenderer(ListCellRenderer<? super E> cellRenderer)
If the prototypeCellValue
property is non-null
, setting the cell renderer also causes the fixedCellWidth
and fixedCellHeight
properties to be re-calculated. 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.
This is a JavaBeans bound property.
cellRenderer
- the ListCellRenderer
that paints list cellspublic Color getSelectionForeground()
DefaultListCellRenderer
uses this color to draw the foreground of items in the selected state, as do the renderers installed by most ListUI
implementations.@BeanProperty(visualUpdate=true, description="The foreground color of selected cells.") public void setSelectionForeground(Color selectionForeground)
DefaultListCellRenderer
uses this color to draw the foreground of items in the selected state, as do the renderers installed by most ListUI
implementations. The default value of this property is defined by the look and feel implementation.
This is a JavaBeans bound property.
selectionForeground
- the Color
to use in the foreground for selected list itemspublic Color getSelectionBackground()
DefaultListCellRenderer
uses this color to draw the background of items in the selected state, as do the renderers installed by most ListUI
implementations.@BeanProperty(visualUpdate=true, description="The background color of selected cells.") public void setSelectionBackground(Color selectionBackground)
DefaultListCellRenderer
uses this color to fill the background of items in the selected state, as do the renderers installed by most ListUI
implementations. The default value of this property is defined by the look and feel implementation.
This is a JavaBeans bound property.
selectionBackground
- the Color
to use for the background of selected cellspublic int getVisibleRowCount()
visibleRowCount
property. See the documentation for setVisibleRowCount(int)
for details on how to interpret this value.visibleRowCount
property.@BeanProperty(visualUpdate=true, description="The preferred number of rows to display without requiring scrolling") public void setVisibleRowCount(int visibleRowCount)
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. 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.
visibleRowCount
- an integer specifying the preferred number of rows to display without requiring scrollingpublic int getLayoutOrientation()
VERTICAL
if the layout is a single column of cells, VERTICAL_WRAP
if the layout is "newspaper style" with the content flowing vertically then horizontally, or HORIZONTAL_WRAP
if the layout is "newspaper style" with the content flowing horizontally then vertically.layoutOrientation
property@BeanProperty(visualUpdate=true, enumerationValues={"JList.VERTICAL","JList.HORIZONTAL_WRAP","JList.VERTICAL_WRAP"}, description="Defines the way list cells are laid out.") public void setLayoutOrientation(int layoutOrientation)
JList
with five cells. Cells can be laid 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
A description of these layouts follows:
Value | Description |
---|---|
VERTICAL |
Cells are laid out vertically in a single column. |
HORIZONTAL_WRAP |
Cells are laid 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. |
VERTICAL_WRAP |
Cells are laid 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. |
VERTICAL
.layoutOrientation
- the new layout orientation, one of: VERTICAL
, HORIZONTAL_WRAP
or VERTICAL_WRAP
IllegalArgumentException
- if layoutOrientation
isn't one of the allowable values@BeanProperty(bound=false) public int getFirstVisibleIndex()
componentOrientation
, the first visible cell is found closest to the list's upper-left corner. In right-to-left orientation, it is found closest to the upper-right corner. If nothing is visible or the list is empty, -1
is returned. Note that the returned cell may only be partially visible.@BeanProperty(bound=false) public int getLastVisibleIndex()
-1
is returned. Note that the returned cell may only be partially visible.public void ensureIndexIsVisible(int index)
scrollRectToVisible
with the bounds of the specified cell. For this method to work, the JList
must be within a JViewport
. If the given index is outside the list's range of cells, this method results in nothing.
index
- the index of the cell to make visible@BeanProperty(bound=false, description="determines whether automatic drag handling is enabled") public void setDragEnabled(boolean b)
true
, and the list's TransferHandler
needs to be non-null
. 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 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
.
b
- whether or not to enable automatic drag handlingHeadlessException
- if b
is true
and GraphicsEnvironment.isHeadless()
returns true
public boolean getDragEnabled()
dragEnabled
propertypublic final void setDropMode(DropMode dropMode)
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
TransferHandler
that accepts drops.dropMode
- the drop mode to useIllegalArgumentException
- if the drop mode is unsupported or null
public final DropMode getDropMode()
@BeanProperty(bound=false) public final JList.DropLocation getDropLocation()
null
if no location is to currently be shown. This method is not meant for querying the drop location from a TransferHandler
, as the drop location is only set after the TransferHandler
's canImport
has returned and has allowed for the location to be shown.
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.
public int getNextMatch(String prefix, int startIndex, Position.Bias bias)
toString
value starts with the given prefix.prefix
- the string to test for a matchstartIndex
- the index for starting the searchbias
- the search direction, either Position.Bias.Forward or Position.Bias.Backward.-1
IllegalArgumentException
- if prefix is null
or startIndex is out of boundspublic String getToolTipText(MouseEvent event)
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. 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, if at a later point JList
is unregistered, by way of a call to setToolTipText(null)
, tips from the renderers will no longer display.
getToolTipText
in class JComponent
event
- the MouseEvent
to fetch the tooltip text forpublic int locationToIndex(Point location)
getCellBounds
. This method 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
.
location
- the coordinates of the point-1
public Point indexToLocation(int index)
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
.
index
- the cell indexnull
public Rectangle getCellBounds(int index0, int index1)
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
.
index0
- the first index in the rangeindex1
- the second index in the rangenull
public ListModel<E> getModel()
JList
component.ListModel
that provides the displayed list of items@BeanProperty(visualUpdate=true, description="The object that contains the data to be drawn by this JList.") public void setModel(ListModel<E> model)
This is a JavaBeans bound property.
model
- the ListModel
that provides the list of items for displayIllegalArgumentException
- if model
is null
public void setListData(E[] listData)
ListModel
from an array of items, and calls setModel
with this model. 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.
listData
- an array of E
containing the items to display in the listpublic void setListData(Vector<? extends E> listData)
ListModel
from a Vector
and calls setModel
with this model. 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.
listData
- a Vector
containing the items to display in the listprotected ListSelectionModel createSelectionModel()
DefaultListSelectionModel
; called during construction to initialize the list's selection model property.DefaultListSelecitonModel
, used to initialize the list's selection model property during constructionpublic ListSelectionModel getSelectionModel()
ListSelectionModel
that maintains the list's selectionsprotected void fireSelectionValueChanged(int firstIndex, int lastIndex, boolean isAdjusting)
ListSelectionListener
s 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. This method constructs a ListSelectionEvent
with this list as the source, and the specified arguments, and sends it to the registered ListSelectionListeners
.
firstIndex
- the first index in the range, <= lastIndex
lastIndex
- the last index in the range, >= firstIndex
isAdjusting
- whether or not this is one in a series of multiple events, where changes are still being madepublic void addListSelectionListener(ListSelectionListener listener)
JList
takes care of listening for selection state changes in the selection model, and notifies the given listener of each change. ListSelectionEvent
s sent to the listener have a source
property set to this list.listener
- the ListSelectionListener
to addpublic void removeListSelectionListener(ListSelectionListener listener)
listener
- the ListSelectionListener
to remove@BeanProperty(bound=false) public ListSelectionListener[] getListSelectionListeners()
ListSelectionListener
s added to this JList
by way of addListSelectionListener
.ListSelectionListener
s on this list, or an empty array if no listeners have been added@BeanProperty(description="The selection model, recording which cells are selected.") public void setSelectionModel(ListSelectionModel selectionModel)
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.
selectionModel
- the ListSelectionModel
that implements the selectionsIllegalArgumentException
- if selectionModel
is null
@BeanProperty(bound=false, enumerationValues={"ListSelectionModel.SINGLE_SELECTION","ListSelectionModel.SINGLE_INTERVAL_SELECTION","ListSelectionModel.MULTIPLE_INTERVAL_SELECTION"}, description="The selection mode.") public void setSelectionMode(int selectionMode)
The following list describes the accepted selection modes:
ListSelectionModel.SINGLE_SELECTION
- Only one list index can be selected at a time. In this mode, setSelectionInterval
and addSelectionInterval
are equivalent, both replacing the current selection with the index represented by the second argument (the "lead"). ListSelectionModel.SINGLE_INTERVAL_SELECTION
- Only one contiguous interval can be selected at a time. In this mode, addSelectionInterval
behaves like 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. ListSelectionModel.MULTIPLE_INTERVAL_SELECTION
- In this mode, there's no restriction on what can be selected. This mode is the default. selectionMode
- the selection modeIllegalArgumentException
- if the selection mode isn't one of those allowedpublic int getSelectionMode()
@BeanProperty(bound=false) public int getAnchorSelectionIndex()
@BeanProperty(bound=false, description="The lead selection index.") public int getLeadSelectionIndex()
@BeanProperty(bound=false) public int getMinSelectionIndex()
-1
if the selection is empty. This is a cover method that delegates to the method of the same name on the list's selection model.-1
@BeanProperty(bound=false) public int getMaxSelectionIndex()
-1
if the selection is empty. This is a cover method that delegates to the method of the same name on the list's selection model.public boolean isSelectedIndex(int index)
true
if the specified index is selected, else false
. This is a cover method that delegates to the method of the same name on the list's selection model.index
- index to be queried for selection statetrue
if the specified index is selected, else false
@BeanProperty(bound=false) public boolean isSelectionEmpty()
true
if nothing is selected, else false
. This is a cover method that delegates to the method of the same name on the list's selection model.true
if nothing is selected, else false
public void clearSelection()
isSelectionEmpty
will return true
. This is a cover method that delegates to the method of the same name on the list's selection model.public void setSelectionInterval(int anchor, int lead)
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. Refer to the documentation of the selection model class being used for details on how values less than 0
are handled.
anchor
- the first index to selectlead
- the last index to selectpublic void addSelectionInterval(int anchor, int lead)
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. Refer to the documentation of the selection model class being used for details on how values less than 0
are handled.
anchor
- the first index to add to the selectionlead
- the last index to add to the selectionpublic void removeSelectionInterval(int index0, int index1)
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. Refer to the documentation of the selection model class being used for details on how values less than 0
are handled.
index0
- the first index to remove from the selectionindex1
- the last index to remove from the selectionpublic void setValueIsAdjusting(boolean b)
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. 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.
b
- the new value for the propertypublic boolean getValueIsAdjusting()
isAdjusting
property. This is a cover method that delegates to the method of the same name on the list's selection model.
isAdjusting
property.public int[] getSelectedIndices()
@BeanProperty(bound=false, description="The index of the selected cell.") public void setSelectedIndex(int index)
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.index
- the index of the cell to selectpublic void setSelectedIndices(int[] indices)
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.indices
- an array of the indices of the cells to select, non-null
NullPointerException
- if the given array is null
@Deprecated @BeanProperty(bound=false) public Object[] getSelectedValues()
getSelectedValuesList()
@BeanProperty(bound=false) public List<E> getSelectedValuesList()
public int getSelectedIndex()
-1
if there is no selection. This method is a cover that delegates to getMinSelectionIndex
.
@BeanProperty(bound=false) public E getSelectedValue()
null
if there is no selection. This is a convenience method that simply returns the model value for getMinSelectionIndex
.
public void setSelectedValue(Object anObject, boolean shouldScroll)
null
, the selection is cleared.anObject
- the object to selectshouldScroll
- true
if the list should scroll to display the selected object, if one exists; otherwise false
@BeanProperty(bound=false) public Dimension getPreferredScrollableViewportSize()
visibleRowCount
rows. The value returned by this method depends on the layout orientation: 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 height of the cell with index 0 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.
getPreferredScrollableViewportSize
in interface Scrollable
visibleRowCount
rowspublic int getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction)
For horizontal scrolling, if the layout orientation is VERTICAL
, then the list's font size is returned (or 1
if the font is null
).
getScrollableUnitIncrement
in interface Scrollable
visibleRect
- the view area visible within the viewportorientation
- SwingConstants.HORIZONTAL
or SwingConstants.VERTICAL
direction
- less or equal to zero to scroll up/back, greater than zero for down/forwardIllegalArgumentException
- if visibleRect
is null
, or orientation
isn't one of SwingConstants.VERTICAL
or SwingConstants.HORIZONTAL
public int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction)
For vertical scrolling, the following rules are used:
visibleRect.height
if the list is empty For horizontal scrolling, when the layout orientation is either VERTICAL_WRAP
or HORIZONTAL_WRAP
:
visibleRect.width
if the list is empty For horizontal scrolling and VERTICAL
orientation, returns visibleRect.width
.
Note that the value of visibleRect
must be the equal to this.getVisibleRect()
.
getScrollableBlockIncrement
in interface Scrollable
visibleRect
- the view area visible within the viewportorientation
- SwingConstants.HORIZONTAL
or SwingConstants.VERTICAL
direction
- less or equal to zero to scroll up/back, greater than zero for down/forwardIllegalArgumentException
- if visibleRect
is null
, or orientation
isn't one of SwingConstants.VERTICAL
or SwingConstants.HORIZONTAL
@BeanProperty(bound=false) public boolean getScrollableTracksViewportWidth()
true
if this JList
is displayed in a JViewport
and the viewport is wider than the list's preferred 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
is itself embedded in a JScrollPane
.
getScrollableTracksViewportWidth
in interface Scrollable
@BeanProperty(bound=false) public boolean getScrollableTracksViewportHeight()
true
if this JList
is displayed in a JViewport
and the viewport is taller than the list'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
is itself embedded in a JScrollPane
.
getScrollableTracksViewportHeight
in interface Scrollable
protected String paramString()
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
.paramString
in class JComponent
String
representation of this JList
.@BeanProperty(bound=false) public AccessibleContext getAccessibleContext()
AccessibleContext
associated with this JList
. For JList
, the AccessibleContext
takes the form of an AccessibleJList
. A new AccessibleJList
instance is created if necessary.
getAccessibleContext
in interface Accessible
getAccessibleContext
in class Component
AccessibleJList
that serves as the AccessibleContext
of this JList
© 1993, 2023, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/javax/swing/JList.html
getSelectedValuesList()