Class JList<E>

java.lang.Object
java.awt.Component
java.awt.Container
javax.swing.JComponent
javax.swing.JList<E>
Type Parameters:
E - the type of the elements of this list
All Implemented Interfaces:
ImageObserver,MenuContainer,Serializable,Accessible,Scrollable
@JavaBean(defaultProperty="UI",description="A component which allows for the selection of one or more objects from a list.")public classJList<E>extendsJComponentimplementsScrollable,Accessible
A component that displays a list of objects and allows the user to select one or more items. A separate model,ListModel, maintains the contents of the list.

It's easy to display an array or Vector of objects, using theJList constructor that automatically builds a read-onlyListModel 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)); }

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

Simple, dynamic-content,JList applications can use theDefaultListModel class to maintain list elements. This class implements theListModel interface and also provides ajava.util.Vector-like API. Applications that need a more customListModel implementation may instead wish to subclassAbstractListModel, which provides basic support for managing and notifying listeners. For example, a read-only implementation ofAbstractListModel:

 // 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 aJList is managed by another separate model, an instance ofListSelectionModel.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 assetSelectedIndex andgetSelectedValue, 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 modeMULTIPLE_INTERVAL_SELECTION. The selection mode can be changed on the selection model directly, or viaJList's cover method. Responsibility for updating the selection model in response to user gestures lies with the list'sListUI.

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

The preferred way to listen for changes in list selection is to addListSelectionListeners directly to theJList.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'sListUI.

Painting of cells in aJList is handled by a delegate called a cell renderer, installed on the list as thecellRenderer property. The renderer provides ajava.awt.Component that is used like a "rubber stamp" to paint the cells. Each time a cell needs to be painted, the list'sListUI asks the cell renderer for the component, moves it into place, and has it paint the contents of the cell by way of itspaint method. A default cell renderer, which uses aJLabel component to render, is installed by the lists'sListUI. 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'sListUI 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 afixedCellWidth andfixedCellHeight 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 aJScrollPane. 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 aMouseListener if you wish to take action on these events. Use thelocationToIndex 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 seeSwing'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 thejava.beans package. Please seeXMLEncoder.

SeeHow to Use Lists inThe Java Tutorial for further documentation.

Since:
1.2
See Also:

  • Field Details

  • Constructor Details

    • JList

      public JList(ListModel<E> dataModel)
      Constructs aJList that displays elements from the specified,non-null, model. AllJList constructors delegate to this one.

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

      Parameters:
      dataModel - the model for the list
      Throws:
      IllegalArgumentException - if the model isnull

    • JList

      public JList(E[] listData)
      Constructs aJList 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 aListModel.

      Attempts to pass anull 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

    • JList

      public JList(Vector<? extendsE> listData)
      Constructs aJList that displays the elements in the specifiedVector. This constructor creates a read-only model for the givenVector, and then delegates to the constructor that takes aListModel.

      Attempts to pass anull value to this method results in undefined behavior and, most likely, exceptions. The created model references the givenVector directly. Attempts to modify theVector after constructing the list results in undefined behavior.

      Parameters:
      listData - theVector to be loaded into the data model,non-null

    • JList

      public JList()
      Constructs aJList with an empty, read-only, model.

  • Method Details

    • getUI

      public ListUI getUI()
      Returns theListUI, the look and feel object that renders this component.
      Overrides:
      getUI in class JComponent
      Returns:
      theListUI object that renders this component

    • setUI

      @BeanProperty(hidden=true,visualUpdate=true,description="The UI object that implements the Component's LookAndFeel.")public void setUI(ListUI ui)
      Sets theListUI, the look and feel object that renders this component.
      Parameters:
      ui - theListUI object
      See Also:

    • updateUI

      public void updateUI()
      Resets theListUI 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 callingSwingUtilities.updateComponentTreeUI on it.
      Overrides:
      updateUI in class JComponent
      See Also:

    • getUIClassID

      @BeanProperty(bound=false)public String getUIClassID()
      Returns"ListUI", theUIDefaults key used to look up the name of thejavax.swing.plaf.ListUI class that defines the look and feel for this component.
      Overrides:
      getUIClassID in class JComponent
      Returns:
      the string "ListUI"
      See Also:

    • getPrototypeCellValue

      public E getPrototypeCellValue()
      Returns the "prototypical" cell value -- a value used to calculate a fixed width and height for cells. This can benull if there is no such value.
      Returns:
      the value of theprototypeCellValue property
      See Also:

    • setPrototypeCellValue

      @BeanProperty(visualUpdate=true,description="The cell prototype value, used to compute cell width and height.")public void setPrototypeCellValue(E prototypeCellValue)
      Sets theprototypeCellValue property, and then (if the new value isnon-null), computes thefixedCellWidth andfixedCellHeight 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 theListUI 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 theprototypeCellValue,fixedCellHeight, andfixedCellWidth properties may be modified by this method,PropertyChangeEvent notifications are only sent when theprototypeCellValue property changes.

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

      The default value of this property isnull.

      This is a JavaBeans bound property.

      Parameters:
      prototypeCellValue - the value on which to basefixedCellWidth andfixedCellHeight
      See Also:

    • getFixedCellWidth

      public int getFixedCellWidth()
      Returns the value of thefixedCellWidth property.
      Returns:
      the fixed cell width
      See Also:

    • setFixedCellWidth

      @BeanProperty(visualUpdate=true,description="Defines a fixed cell width when greater than zero.")public void setFixedCellWidth(int width)
      Sets a fixed value to be used for the width of every cell in the list. Ifwidth is -1, cell widths are computed in theListUI by applyinggetPreferredSize to the cell renderer 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 for all cells in the list
      See Also:

    • getFixedCellHeight

      public int getFixedCellHeight()
      Returns the value of thefixedCellHeight property.
      Returns:
      the fixed cell height
      See Also:

    • setFixedCellHeight

      @BeanProperty(visualUpdate=true,description="Defines a fixed cell height when greater than zero.")public void setFixedCellHeight(int height)
      Sets a fixed value to be used for the height of every cell in the list. Ifheight is -1, cell heights are computed in theListUI by applyinggetPreferredSize to the cell renderer component for each list element.

      The default value of this property is-1.

      This is a JavaBeans bound property.

      Parameters:
      height - the height to be used for all cells in the list
      See Also:

    • getCellRenderer

      public ListCellRenderer<? superE> getCellRenderer()
      Returns the object responsible for painting list items.
      Returns:
      the value of thecellRenderer property
      See Also:

    • setCellRenderer

      @BeanProperty(visualUpdate=true,description="The component used to draw the cells.")public void setCellRenderer(ListCellRenderer<? superE> 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 theclass level documentation.

      If theprototypeCellValue property isnon-null, setting the cell renderer also causes thefixedCellWidth andfixedCellHeight properties to be re-calculated. Only onePropertyChangeEvent is generated however - for thecellRenderer property.

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

      This is a JavaBeans bound property.

      Parameters:
      cellRenderer - theListCellRenderer that paints list cells
      See Also:

    • 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 mostListUI implementations.
      Returns:
      the color to draw the foreground of selected items
      See Also:

    • setSelectionForeground

      @BeanProperty(visualUpdate=true,description="The foreground color of selected cells.")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 mostListUI implementations.

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

      This is a JavaBeans bound property.

      Parameters:
      selectionForeground - theColor to use in the foreground for selected list items
      See Also:

    • 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 mostListUI implementations.
      Returns:
      the color to draw the background of selected items
      See Also:

    • setSelectionBackground

      @BeanProperty(visualUpdate=true,description="The background color of selected cells.")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 mostListUI implementations.

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

      This is a JavaBeans bound property.

      Parameters:
      selectionBackground - theColor to use for the background of selected cells
      See Also:

    • getVisibleRowCount

      public int getVisibleRowCount()
      Returns the value of thevisibleRowCount property. See the documentation forsetVisibleRowCount(int) for details on how to interpret this value.
      Returns:
      the value of thevisibleRowCount property.
      See Also:

    • setVisibleRowCount

      @BeanProperty(visualUpdate=true,description="The preferred number of rows to display without requiring scrolling")public void setVisibleRowCount(int visibleRowCount)
      Sets thevisibleRowCount property, which has different meanings depending on the layout orientation: For aVERTICAL layout orientation, this sets the preferred number of rows to display without requiring scrolling; for other orientations, it affects the wrapping of cells.

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

      InHORIZONTAL_WRAP andVERTICAL_WRAP orientations:
      This affects how cells are wrapped. See the documentation ofsetLayoutOrientation(int) for more details.

      The default value of this property is8.

      Calling this method with a negative value results in the property being set to0.

      This is a JavaBeans bound property.

      Parameters:
      visibleRowCount - an integer specifying the preferred number of rows to display without requiring scrolling
      See Also:

    • getLayoutOrientation

      public 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, orHORIZONTAL_WRAP if the layout is "newspaper style" with the content flowing horizontally then vertically.
      Returns:
      the value of thelayoutOrientation property
      Since:
      1.4
      See Also:

    • setLayoutOrientation

      @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)
      Defines the way list cells are laid out. Consider aJList 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:

      Describes layouts VERTICAL,HORIZONTAL_WRAP, and VERTICAL_WRAP
      ValueDescription
      VERTICALCells are laid out vertically in a single column.
      HORIZONTAL_WRAPCells are laid out horizontally, wrapping to a new row as necessary. If thevisibleRowCount 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 ensurevisibleRowCount rows in the list.
      VERTICAL_WRAPCells are laid out vertically, wrapping to a new column as necessary. If thevisibleRowCount property is less than or equal to zero, wrapping is determined by the height of the list; otherwise wrapping is done atvisibleRowCount rows.
      The default value of this property isVERTICAL.

      Parameters:
      layoutOrientation - the new layout orientation, one of:VERTICAL,HORIZONTAL_WRAP orVERTICAL_WRAP
      Throws:
      IllegalArgumentException - iflayoutOrientation isn't one of the allowable values
      Since:
      1.4
      See Also:

    • getFirstVisibleIndex

      @BeanProperty(bound=false)public int getFirstVisibleIndex()
      Returns the smallest list index that is currently visible. In a left-to-rightcomponentOrientation, 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.
      Returns:
      the index of the first visible cell
      See Also:

    • getLastVisibleIndex

      @BeanProperty(bound=false)public int getLastVisibleIndex()
      Returns the largest list index that is currently visible. If nothing is visible or the list is empty,-1 is returned. Note that the returned cell may only be partially visible.
      Returns:
      the index of the last visible cell
      See Also:

    • ensureIndexIsVisible

      public void ensureIndexIsVisible(int index)
      Scrolls the list within an enclosing viewport to make the specified cell completely visible. This callsscrollRectToVisible with the bounds of the specified cell. For this method to work, theJList must be within aJViewport.

      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:

    • setDragEnabled

      @BeanProperty(bound=false,description="determines whether automatic drag handling is enabled")public void setDragEnabled(boolean b)
      Turns on or off automatic drag handling. In order to enable automatic drag handling, this property should be set totrue, and the list'sTransferHandler needs to benon-null. The default value of thedragEnabled property isfalse.

      The job of honoring this property, and recognizing a user drag gesture, lies with the look and feel implementation, and in particular, the list'sListUI. When automatic drag handling is enabled, most look and feels (including those that subclassBasicLookAndFeel) 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 totrue 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 callingexportAsDrag on the list'sTransferHandler.

      Parameters:
      b - whether or not to enable automatic drag handling
      Throws:
      HeadlessException - ifb istrue andGraphicsEnvironment.isHeadless() returnstrue
      Since:
      1.4
      See Also:

    • getDragEnabled

      public boolean getDragEnabled()
      Returns whether or not automatic drag handling is enabled.
      Returns:
      the value of thedragEnabled property
      Since:
      1.4
      See Also:

    • setDropMode

      public final void setDropMode(DropMode dropMode)
      Sets the drop mode for this component. For backward compatibility, the default for this property isDropMode.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 aTransferHandler that accepts drops.

      Parameters:
      dropMode - the drop mode to use
      Throws:
      IllegalArgumentException - if the drop mode is unsupported ornull
      Since:
      1.6
      See Also:

    • getDropMode

      public final DropMode getDropMode()
      Returns the drop mode for this component.
      Returns:
      the drop mode for this component
      Since:
      1.6
      See Also:

    • getDropLocation

      @BeanProperty(bound=false)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, ornull if no location is to currently be shown.

      This method is not meant for querying the drop location from aTransferHandler, as the drop location is only set after theTransferHandler'scanImport 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'sListUI, 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:

    • getNextMatch

      public int getNextMatch(String prefix, int startIndex,Position.Bias bias)
      Returns the next list element whosetoString value starts with the given 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 isnull 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 overridesJComponent'sgetToolTipText 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 usingsetToolTipText on your cell renderer component.

      Note: ForJList to properly display the tooltips of its renderers in this manner,JList must be a registered component with theToolTipManager. This registration is done automatically in the constructor. However, if at a later pointJList is unregistered, by way of a call tosetToolTipText(null), tips from the renderers will no longer display.

      Overrides:
      getToolTipText in class JComponent
      Parameters:
      event - theMouseEvent to fetch the tooltip text for
      Returns:
      a string containing the tooltip
      See Also:

    • 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 bygetCellBounds. 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'sListUI. It returns-1 if the list has noListUI.

      Parameters:
      location - the coordinates of the point
      Returns:
      the cell index closest to the given location, or-1

    • indexToLocation

      public Point indexToLocation(int index)
      Returns the origin of the specified item in the list's coordinate system. This method returnsnull if the index isn't valid.

      This is a cover method that delegates to the method of the same name in the list'sListUI. It returnsnull if the list has noListUI.

      Parameters:
      index - the cell index
      Returns:
      the origin of the cell, ornull

    • 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.

      If the smaller index is outside the list's range of cells, this method returnsnull. 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'sListUI. It returnsnull if the list has noListUI.

      Parameters:
      index0 - the first index in the range
      index1 - the second index in the range
      Returns:
      the bounding rectangle for the range of cells, ornull

    • getModel

      public ListModel<E> getModel()
      Returns the data model that holds the list of items displayed by theJList component.
      Returns:
      theListModel that provides the displayed list of items
      See Also:

    • setModel

      @BeanProperty(visualUpdate=true,description="The object that contains the data to be drawn by this JList.")public void setModel(ListModel<E> model)
      Sets the model that represents the contents or "value" of the list, notifies property change listeners, and then clears the list's selection.

      This is a JavaBeans bound property.

      Parameters:
      model - theListModel that provides the list of items for display
      Throws:
      IllegalArgumentException - ifmodel isnull
      See Also:

    • setListData

      public void setListData(E[] listData)
      Constructs a read-onlyListModel from an array of items, and callssetModel with this model.

      Attempts to pass anull 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 ofE containing the items to display in the list
      See Also:

    • setListData

      public void setListData(Vector<? extendsE> listData)
      Constructs a read-onlyListModel from aVector and callssetModel with this model.

      Attempts to pass anull value to this method results in undefined behavior and, most likely, exceptions. The created model references the givenVector directly. Attempts to modify theVector after invoking this method results in undefined behavior.

      Parameters:
      listData - aVector containing the items to display in the list
      See Also:

    • createSelectionModel

      protected ListSelectionModel createSelectionModel()
      Returns an instance ofDefaultListSelectionModel; called during construction to initialize the list's selection model property.
      Returns:
      aDefaultListSelectionModel, used to initialize the list's selection model property during construction
      See Also:

    • 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:
      theListSelectionModel that maintains the list's selections
      See Also:

    • fireSelectionValueChanged

      protected void fireSelectionValueChanged(int firstIndex, int lastIndex, boolean isAdjusting)
      NotifiesListSelectionListeners 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 aListSelectionEvent with this list as the source, and the specified arguments, and sends it to the registeredListSelectionListeners.

      Parameters:
      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 made
      See Also:

    • 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 asource property set to this list.
      Parameters:
      listener - theListSelectionListener to add
      See Also:

    • removeListSelectionListener

      public void removeListSelectionListener(ListSelectionListener listener)
      Removes a selection listener from the list.
      Parameters:
      listener - theListSelectionListener to remove
      See Also:

    • getListSelectionListeners

      @BeanProperty(bound=false)public ListSelectionListener[] getListSelectionListeners()
      Returns an array of all theListSelectionListeners added to thisJList by way ofaddListSelectionListener.
      Returns:
      all of theListSelectionListeners on this list, or an empty array if no listeners have been added
      Since:
      1.4
      See Also:

    • setSelectionModel

      @BeanProperty(description="The selection model, recording which cells are selected.")public void setSelectionModel(ListSelectionModel selectionModel)
      Sets theselectionModel for the list to a non-nullListSelectionModel 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 - theListSelectionModel that implements the selections
      Throws:
      IllegalArgumentException - ifselectionModel isnull
      See Also:

    • setSelectionMode

      @BeanProperty(bound=false,enumerationValues={"ListSelectionModel.SINGLE_SELECTION","ListSelectionModel.SINGLE_INTERVAL_SELECTION","ListSelectionModel.MULTIPLE_INTERVAL_SELECTION"},description="The selection mode.")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:

      • ListSelectionModel.SINGLE_SELECTION - Only one list index can be selected at a time. In this mode,setSelectionInterval andaddSelectionInterval 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 likesetSelectionInterval (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.

      Parameters:
      selectionMode - the selection mode
      Throws:
      IllegalArgumentException - if the selection mode isn't one of those allowed
      See Also:

    • 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:
      the current selection mode
      See Also:

    • getAnchorSelectionIndex

      @BeanProperty(bound=false)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 anchor selection index
      See Also:

    • getLeadSelectionIndex

      @BeanProperty(bound=false,description="The lead selection index.")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 lead selection index
      See Also:

    • getMinSelectionIndex

      @BeanProperty(bound=false)public int getMinSelectionIndex()
      Returns the smallest selected cell index, or-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.
      Returns:
      the smallest selected cell index, or-1
      See Also:

    • getMaxSelectionIndex

      @BeanProperty(bound=false)public int getMaxSelectionIndex()
      Returns the largest selected cell index, or-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.
      Returns:
      the largest selected cell index
      See Also:

    • isSelectedIndex

      public boolean isSelectedIndex(int index)
      Returnstrue if the specified index is selected, elsefalse. This is a cover method that delegates to the method of the same name on the list's selection model.
      Parameters:
      index - index to be queried for selection state
      Returns:
      true if the specified index is selected, elsefalse
      See Also:

    • isSelectionEmpty

      @BeanProperty(bound=false)public boolean isSelectionEmpty()
      Returnstrue if nothing is selected, elsefalse. This is a cover method that delegates to the method of the same name on the list's selection model.
      Returns:
      true if nothing is selected, elsefalse
      See Also:

    • clearSelection

      public void clearSelection()
      Clears the selection; after calling this method,isSelectionEmpty will returntrue. This is a cover method that delegates to the method of the same name on the list's selection model.
      See Also:

    • setSelectionInterval

      public void setSelectionInterval(int anchor, int lead)
      Selects the specified interval. Bothanchor andlead indices are included.anchor doesn't have to be less than or equal tolead. 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 than0 are handled.

      Parameters:
      anchor - the first index to select
      lead - the last index to select
      See Also:

    • addSelectionInterval

      public void addSelectionInterval(int anchor, int lead)
      Sets the selection to be the union of the specified interval with current selection. Both theanchor andlead indices are included.anchor doesn't have to be less than or equal tolead. 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 than0 are handled.

      Parameters:
      anchor - the first index to add to the selection
      lead - the last index to add to the selection
      See Also:

    • 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 theindex0 andindex1 indices are removed.index0 doesn't have to be less than or equal toindex1. 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 than0 are handled.

      Parameters:
      index0 - the first index to remove from the selection
      index1 - the last index to remove from the selection
      See Also:

    • setValueIsAdjusting

      public void setValueIsAdjusting(boolean b)
      Sets the selection model'svalueIsAdjusting property. Whentrue, 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 totrue when the drag is initiated and set tofalse 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 forListSelectionModel.setValueIsAdjusting(boolean) for more details.

      Parameters:
      b - the new value for the property
      See Also:

    • getValueIsAdjusting

      public boolean getValueIsAdjusting()
      Returns the value of the selection model'sisAdjusting property.

      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'sisAdjusting property.
      See Also:

    • getSelectedIndices

      public int[] getSelectedIndices()
      Returns an array of all of the selected indices, in increasing order.
      Returns:
      all of the selected indices, in increasing order, or an empty array if nothing is selected
      See Also:

    • setSelectedIndex

      @BeanProperty(bound=false,description="The index of the selected cell.")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 usessetSelectionInterval on the selection model. Refer to the documentation for the selection model class being used for details on how values less than0 are handled.
      Parameters:
      index - the index of the cell to select
      See Also:

    • 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 usesaddSelectionInterval 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 than0 are handled.
      Parameters:
      indices - an array of the indices of the cells to select,non-null
      Throws:
      NullPointerException - if the given array isnull
      See Also:

    • getSelectedValues

      @Deprecated@BeanProperty(bound=false)public Object[] getSelectedValues()
      Deprecated.
      As of JDK 1.7, replaced bygetSelectedValuesList()
      Returns an array of all the selected values, in increasing order based on their indices in the list.
      Returns:
      the selected values, or an empty array if nothing is selected
      See Also:

    • getSelectedValuesList

      @BeanProperty(bound=false)public List<E> getSelectedValuesList()
      Returns a list of all the selected items, in increasing order based on their indices in the list.
      Returns:
      the selected items, or an empty list if nothing is selected
      Since:
      1.7
      See Also:

    • 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.

      This method is a cover that delegates togetMinSelectionIndex.

      Returns:
      the smallest selected cell index
      See Also:

    • getSelectedValue

      @BeanProperty(bound=false)public E 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. Returnsnull if there is no selection.

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

      Returns:
      the first selected value
      See Also:

    • setSelectedValue

      public void setSelectedValue(Object anObject, boolean shouldScroll)
      Selects the specified object from the list. If the object passed isnull, the selection is cleared.
      Parameters:
      anObject - the object to select
      shouldScroll -true if the list should scroll to display the selected object, if one exists; otherwisefalse

    • getPreferredScrollableViewportSize

      @BeanProperty(bound=false)public Dimension getPreferredScrollableViewportSize()
      Computes the size of viewport needed to displayvisibleRowCount rows. The value returned by this method depends on the layout orientation:

      VERTICAL:
      This is trivial if bothfixedCellWidth andfixedCellHeight have been set (either explicitly or by specifying a prototype cell value). The width is simply thefixedCellWidth plus the list's horizontal insets. The height is thefixedCellHeight multiplied by thevisibleRowCount, plus the list's vertical insets.

      If eitherfixedCellWidth orfixedCellHeight haven't been specified, heuristics are used. If the model is empty, the width is thefixedCellWidth, if greater than0, or a hard-coded value of256. The height is thefixedCellHeight multiplied byvisibleRowCount, iffixedCellHeight is greater than0, otherwise it is a hard-coded value of16 multiplied byvisibleRowCount.

      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 thevisibleRowCount, plus the list's vertical insets.

      VERTICAL_WRAP orHORIZONTAL_WRAP:
      This method simply returns the value fromgetPreferredSize. The list'sListUI is expected to overridegetPreferredSize to return an appropriate value.

      Specified by:
      getPreferredScrollableViewportSize in interface Scrollable
      Returns:
      a dimension containing the size of the viewport needed to displayvisibleRowCount rows
      See Also:

    • 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, if the layout orientation isVERTICAL, then the list's font size is returned (or1 if the font isnull).

      Specified by:
      getScrollableUnitIncrement in interface Scrollable
      Parameters:
      visibleRect - the view area visible within the viewport
      orientation -SwingConstants.HORIZONTAL orSwingConstants.VERTICAL
      direction - less or equal to zero to scroll up/back, greater than zero for down/forward
      Returns:
      the "unit" increment for scrolling in the specified direction; always positive
      Throws:
      IllegalArgumentException - ifvisibleRect isnull, ororientation isn't one ofSwingConstants.VERTICAL orSwingConstants.HORIZONTAL
      See Also:

    • 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:

      • if scrolling down, returns the distance to scroll so that the last visible element becomes the first completely visible element
      • if scrolling up, returns the distance to scroll so that the first visible element becomes the last completely visible element
      • returnsvisibleRect.height if the list is empty

      For horizontal scrolling, when the layout orientation is eitherVERTICAL_WRAP orHORIZONTAL_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
      • returnsvisibleRect.width if the list is empty

      For horizontal scrolling andVERTICAL orientation, returnsvisibleRect.width.

      Note that the value ofvisibleRect must be the equal tothis.getVisibleRect().

      Specified by:
      getScrollableBlockIncrement in interface Scrollable
      Parameters:
      visibleRect - the view area visible within the viewport
      orientation -SwingConstants.HORIZONTAL orSwingConstants.VERTICAL
      direction - less or equal to zero to scroll up/back, greater than zero for down/forward
      Returns:
      the "block" increment for scrolling in the specified direction; always positive
      Throws:
      IllegalArgumentException - ifvisibleRect isnull, ororientation isn't one ofSwingConstants.VERTICAL orSwingConstants.HORIZONTAL
      See Also:

    • getScrollableTracksViewportWidth

      @BeanProperty(bound=false)public boolean getScrollableTracksViewportWidth()
      Returnstrue if thisJList is displayed in aJViewport and the viewport is wider than the list's preferred width, or if the layout orientation isHORIZONTAL_WRAP andvisibleRowCount <= 0; otherwise returnsfalse.

      Iffalse, then don't track the viewport's width. This allows horizontal scrolling if theJViewport is itself embedded in aJScrollPane.

      Specified by:
      getScrollableTracksViewportWidth in interface Scrollable
      Returns:
      whether or not an enclosing viewport should force the list's width to match its own
      See Also:

    • getScrollableTracksViewportHeight

      @BeanProperty(bound=false)public boolean getScrollableTracksViewportHeight()
      Returnstrue if thisJList is displayed in aJViewport and the viewport is taller than the list's preferred height, or if the layout orientation isVERTICAL_WRAP andvisibleRowCount <= 0; otherwise returnsfalse.

      Iffalse, then don't track the viewport's height. This allows vertical scrolling if theJViewport is itself embedded in aJScrollPane.

      Specified by:
      getScrollableTracksViewportHeight in interface Scrollable
      Returns:
      whether or not an enclosing viewport should force the list's height to match its own
      See Also:

    • paramString

      protected String paramString()
      Returns aString representation of thisJList. This method is intended to be used only for debugging purposes, and the content and format of the returnedString may vary between implementations. The returnedString may be empty, but may not benull.
      Overrides:
      paramString in class JComponent
      Returns:
      aString representation of thisJList.

    • getAccessibleContext

      @BeanProperty(bound=false)public AccessibleContext getAccessibleContext()
      Gets theAccessibleContext associated with thisJList. ForJList, theAccessibleContext takes the form of anAccessibleJList.

      A newAccessibleJList instance is created if necessary.

      Specified by:
      getAccessibleContext in interface Accessible
      Overrides:
      getAccessibleContext in class Component
      Returns:
      anAccessibleJList that serves as theAccessibleContext of thisJList