Java™ Platform
Standard Ed. 6

javax.swing.plaf.basic
Class BasicListUI

java.lang.Object
  extended by javax.swing.plaf.ComponentUI
      extended by javax.swing.plaf.ListUI
          extended by javax.swing.plaf.basic.BasicListUI

public class BasicListUI
extends ListUI

An extensible implementation of ListUI.

BasicListUI instances cannot be shared between multiple lists.


Nested Class Summary
 class BasicListUI.FocusHandler
          This inner class is marked "public" due to a compiler bug.
 class BasicListUI.ListDataHandler
          The ListDataListener that's added to the JLists model at installUI time, and whenever the JList.model property changes.
 class BasicListUI.ListSelectionHandler
          The ListSelectionListener that's added to the JLists selection model at installUI time, and whenever the JList.selectionModel property changes.
 class BasicListUI.MouseInputHandler
          Mouse input, and focus handling for JList.
 class BasicListUI.PropertyChangeHandler
          The PropertyChangeListener that's added to the JList at installUI time.
 
Field Summary
protected  int cellHeight
           
protected  int[] cellHeights
           
protected static int cellRendererChanged
           
protected  int cellWidth
           
protected static int fixedCellHeightChanged
           
protected static int fixedCellWidthChanged
           
protected  FocusListener focusListener
           
protected static int fontChanged
           
protected  JList list
           
protected  ListDataListener listDataListener
           
protected  ListSelectionListener listSelectionListener
           
protected static int modelChanged
           
protected  MouseInputListener mouseInputListener
           
protected  PropertyChangeListener propertyChangeListener
           
protected static int prototypeCellValueChanged
           
protected  CellRendererPane rendererPane
           
protected static int selectionModelChanged
           
protected  int updateLayoutStateNeeded
           
 
Constructor Summary
BasicListUI()
           
 
Method Summary
protected  int convertRowToY(int row)
          Return the JList relative Y coordinate of the origin of the specified row or -1 if row isn't valid.
protected  int convertYToRow(int y0)
          Convert the JList relative coordinate to the row that contains it, based on the current layout.
protected  FocusListener createFocusListener()
           
protected  ListDataListener createListDataListener()
          Creates an instance of ListDataListener that's added to the JLists by model as needed.
protected  ListSelectionListener createListSelectionListener()
          Creates an instance of ListSelectionHandler that's added to the JLists by selectionModel as needed.
protected  MouseInputListener createMouseInputListener()
          Creates a delegate that implements MouseInputListener.
protected  PropertyChangeListener createPropertyChangeListener()
          Creates an instance of PropertyChangeHandler that's added to the JList by installUI().
static ComponentUI createUI(JComponent list)
          Returns a new instance of BasicListUI.
 int getBaseline(JComponent c, int width, int height)
          Returns the baseline.
 Component.BaselineResizeBehavior getBaselineResizeBehavior(JComponent c)
          Returns an enum indicating how the baseline of the component changes as the size changes.
 Rectangle getCellBounds(JList list, int index1, int index2)
          Returns the bounding rectangle, in the given list's coordinate system, for the range of cells specified by the two indices.
 Dimension getPreferredSize(JComponent c)
          The preferredSize of the list depends upon the layout orientation.
protected  int getRowHeight(int row)
          Returns the height of the specified row based on the current layout.
 Point indexToLocation(JList list, int index)
          Returns the origin in the given JList, of the specified item, in the list's coordinate system.
protected  void installDefaults()
          Initialize JList properties, e.g.
protected  void installKeyboardActions()
          Registers the keyboard bindings on the JList that the BasicListUI is associated with.
protected  void installListeners()
          Create and install the listeners for the JList, its model, and its selectionModel.
 void installUI(JComponent c)
          Initializes this.list by calling installDefaults(), installListeners(), and installKeyboardActions() in order.
 int locationToIndex(JList list, Point location)
          Returns the cell index in the specified JList closest to the given location in the list's coordinate system.
protected  void maybeUpdateLayoutState()
          If updateLayoutStateNeeded is non zero, call updateLayoutState() and reset updateLayoutStateNeeded.
 void paint(Graphics g, JComponent c)
          Paint the rows that intersect the Graphics objects clipRect.
protected  void paintCell(Graphics g, int row, Rectangle rowBounds, ListCellRenderer cellRenderer, ListModel dataModel, ListSelectionModel selModel, int leadIndex)
          Paint one List cell: compute the relevant state, get the "rubber stamp" cell renderer component, and then use the CellRendererPane to paint it.
protected  void selectNextIndex()
          Selected the previous row and force it to be visible.
protected  void selectPreviousIndex()
          Selected the previous row and force it to be visible.
protected  void uninstallDefaults()
          Set the JList properties that haven't been explicitly overridden to null.
protected  void uninstallKeyboardActions()
          Unregisters keyboard actions installed from installKeyboardActions.
protected  void uninstallListeners()
          Remove the listeners for the JList, its model, and its selectionModel.
 void uninstallUI(JComponent c)
          Uninitializes this.list by calling uninstallListeners(), uninstallKeyboardActions(), and uninstallDefaults() in order.
protected  void updateLayoutState()
          Recompute the value of cellHeight or cellHeights based and cellWidth, based on the current font and the current values of fixedCellWidth, fixedCellHeight, and prototypeCellValue.
 
Methods inherited from class javax.swing.plaf.ComponentUI
contains, getAccessibleChild, getAccessibleChildrenCount, getMaximumSize, getMinimumSize, update
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

list

protected JList list

rendererPane

protected CellRendererPane rendererPane

focusListener

protected FocusListener focusListener

mouseInputListener

protected MouseInputListener mouseInputListener

listSelectionListener

protected ListSelectionListener listSelectionListener

listDataListener

protected ListDataListener listDataListener

propertyChangeListener

protected PropertyChangeListener propertyChangeListener

cellHeights

protected int[] cellHeights

cellHeight

protected int cellHeight

cellWidth

protected int cellWidth

updateLayoutStateNeeded

protected int updateLayoutStateNeeded

modelChanged

protected static final int modelChanged
See Also:
Constant Field Values

selectionModelChanged

protected static final int selectionModelChanged
See Also:
Constant Field Values

fontChanged

protected static final int fontChanged
See Also:
Constant Field Values

fixedCellWidthChanged

protected static final int fixedCellWidthChanged
See Also:
Constant Field Values

fixedCellHeightChanged

protected static final int fixedCellHeightChanged
See Also:
Constant Field Values

prototypeCellValueChanged

protected static final int prototypeCellValueChanged
See Also:
Constant Field Values

cellRendererChanged

protected static final int cellRendererChanged
See Also:
Constant Field Values
Constructor Detail

BasicListUI

public BasicListUI()
Method Detail

paintCell

protected void paintCell(Graphics g,
                         int row,
                         Rectangle rowBounds,
                         ListCellRenderer cellRenderer,
                         ListModel dataModel,
                         ListSelectionModel selModel,
                         int leadIndex)
Paint one List cell: compute the relevant state, get the "rubber stamp" cell renderer component, and then use the CellRendererPane to paint it. Subclasses may want to override this method rather than paint().

See Also:
paint(java.awt.Graphics, javax.swing.JComponent)

paint

public void paint(Graphics g,
                  JComponent c)
Paint the rows that intersect the Graphics objects clipRect. This method calls paintCell as necessary. Subclasses may want to override these methods.

Overrides:
paint in class ComponentUI
Parameters:
g - the Graphics context in which to paint
c - the component being painted; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components
See Also:
paintCell(java.awt.Graphics, int, java.awt.Rectangle, javax.swing.ListCellRenderer, javax.swing.ListModel, javax.swing.ListSelectionModel, int)

getBaseline

public int getBaseline(JComponent c,
                       int width,
                       int height)
Returns the baseline.

Overrides:
getBaseline in class ComponentUI
Parameters:
c - JComponent baseline is being requested for
width - the width to get the baseline for
height - the height to get the baseline for
Returns:
baseline or a value < 0 indicating there is no reasonable baseline
Throws:
NullPointerException - if c is null
IllegalArgumentException - if width or height is < 0
Since:
1.6
See Also:
JComponent.getBaseline(int, int)

getBaselineResizeBehavior

public Component.BaselineResizeBehavior getBaselineResizeBehavior(JComponent c)
Returns an enum indicating how the baseline of the component changes as the size changes.

Overrides:
getBaselineResizeBehavior in class ComponentUI
Parameters:
c - JComponent to return baseline resize behavior for
Returns:
an enum indicating how the baseline changes as the component size changes
Throws:
NullPointerException - if c is null
Since:
1.6
See Also:
JComponent.getBaseline(int, int)

getPreferredSize

public Dimension getPreferredSize(JComponent c)
The preferredSize of the list depends upon the layout orientation.
Layout OrientationPreferred Size
JList.VERTICAL The preferredSize of the list is total height of the rows and the maximum width of the cells. If JList.fixedCellHeight is specified then the total height of the rows is just (cellVerticalMargins + fixedCellHeight) * model.getSize() where rowVerticalMargins is the space we allocate for drawing the yellow focus outline. Similarly if fixedCellWidth is specified then we just use that.
JList.VERTICAL_WRAP If the visible row count is greater than zero, the preferredHeight is the maximum cell height * visibleRowCount. If the visible row count is <= 0, the preferred height is either the current height of the list, or the maximum cell height, whichever is bigger. The preferred width is than the maximum cell width * number of columns needed. Where the number of columns needs is list.height / max cell height. Max cell height is either the fixed cell height, or is determined by iterating through all the cells to find the maximum height from the ListCellRenderer.
JList.HORIZONTAL_WRAP If the visible row count is greater than zero, the preferredHeight is the maximum cell height * adjustedRowCount. Where visibleRowCount is used to determine the number of columns. Because this lays out horizontally the number of rows is then determined from the column count. For example, lets say you have a model with 10 items and the visible row count is 8. The number of columns needed to display this is 2, but you no longer need 8 rows to display this, you only need 5, thus the adjustedRowCount is 5.

If the visible row count is <= 0, the preferred height is dictated by the number of columns, which will be as many as can fit in the width of the JList (width / max cell width), with at least one column. The preferred height then becomes the model size / number of columns * maximum cell height. Max cell height is either the fixed cell height, or is determined by iterating through all the cells to find the maximum height from the ListCellRenderer.

The above specifies the raw preferred width and height. The resulting preferred width is the above width + insets.left + insets.right and the resulting preferred height is the above height + insets.top + insets.bottom. Where the Insets are determined from list.getInsets().

Overrides:
getPreferredSize in class ComponentUI
Parameters:
c - The JList component.
Returns:
The total size of the list.
See Also:
JComponent.getPreferredSize(), LayoutManager.preferredLayoutSize(java.awt.Container)

selectPreviousIndex

protected void selectPreviousIndex()
Selected the previous row and force it to be visible.

See Also:
JList.ensureIndexIsVisible(int)

selectNextIndex

protected void selectNextIndex()
Selected the previous row and force it to be visible.

See Also:
JList.ensureIndexIsVisible(int)

installKeyboardActions

protected void installKeyboardActions()
Registers the keyboard bindings on the JList that the BasicListUI is associated with. This method is called at installUI() time.

See Also:
installUI(javax.swing.JComponent)

uninstallKeyboardActions

protected void uninstallKeyboardActions()
Unregisters keyboard actions installed from installKeyboardActions. This method is called at uninstallUI() time - subclassess should ensure that all of the keyboard actions registered at installUI time are removed here.

See Also:
installUI(javax.swing.JComponent)

installListeners

protected void installListeners()
Create and install the listeners for the JList, its model, and its selectionModel. This method is called at installUI() time.

See Also:
installUI(javax.swing.JComponent), uninstallListeners()

uninstallListeners

protected void uninstallListeners()
Remove the listeners for the JList, its model, and its selectionModel. All of the listener fields, are reset to null here. This method is called at uninstallUI() time, it should be kept in sync with installListeners.

See Also:
uninstallUI(javax.swing.JComponent), installListeners()

installDefaults

protected void installDefaults()
Initialize JList properties, e.g. font, foreground, and background, and add the CellRendererPane. The font, foreground, and background properties are only set if their current value is either null or a UIResource, other properties are set if the current value is null.

See Also:
uninstallDefaults(), installUI(javax.swing.JComponent), CellRendererPane

uninstallDefaults

protected void uninstallDefaults()
Set the JList properties that haven't been explicitly overridden to null. A property is considered overridden if its current value is not a UIResource.

See Also:
installDefaults(), uninstallUI(javax.swing.JComponent), CellRendererPane

installUI

public void installUI(JComponent c)
Initializes this.list by calling installDefaults(), installListeners(), and installKeyboardActions() in order.

Overrides:
installUI in class ComponentUI
Parameters:
c - the component where this UI delegate is being installed
See Also:
installDefaults(), installListeners(), installKeyboardActions()

uninstallUI

public void uninstallUI(JComponent c)
Uninitializes this.list by calling uninstallListeners(), uninstallKeyboardActions(), and uninstallDefaults() in order. Sets this.list to null.

Overrides:
uninstallUI in class ComponentUI
Parameters:
c - the component from which this UI delegate is being removed; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components
See Also:
uninstallListeners(), uninstallKeyboardActions(), uninstallDefaults()

createUI

public static ComponentUI createUI(JComponent list)
Returns a new instance of BasicListUI. BasicListUI delegates are allocated one per JList.

Returns:
A new ListUI implementation for the Windows look and feel.

locationToIndex

public int locationToIndex(JList list,
                           Point location)
Returns the cell index in the specified JList closest to the given location in the list's coordinate system. To determine if the cell actually contains the specified location, compare the point against the cell's bounds, as provided by getCellBounds. This method returns -1 if the list's model is empty.

Specified by:
locationToIndex in class ListUI
Parameters:
list - the list
location - the coordinates of the point
Returns:
the cell index closest to the given location, or -1
Throws:
NullPointerException - if location is null

indexToLocation

public Point indexToLocation(JList list,
                             int index)
Returns the origin in the given JList, of the specified item, in the list's coordinate system. Returns null if the index isn't valid.

Specified by:
indexToLocation in class ListUI
Parameters:
list - the list
index - the cell index
Returns:
the origin of the cell, or null

getCellBounds

public Rectangle getCellBounds(JList list,
                               int index1,
                               int index2)
Returns the bounding rectangle, in the given list's coordinate system, for the range of cells specified by the two indices. The indices can be supplied in any order.

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.

Specified by:
getCellBounds in class ListUI
Parameters:
list - the list
index1 - the first index in the range
index2 - the second index in the range
Returns:
the bounding rectangle for the range of cells, or null

getRowHeight

protected int getRowHeight(int row)
Returns the height of the specified row based on the current layout.

Returns:
The specified row height or -1 if row isn't valid.
See Also:
convertYToRow(int), convertRowToY(int), updateLayoutState()

convertYToRow

protected int convertYToRow(int y0)
Convert the JList relative coordinate to the row that contains it, based on the current layout. If y0 doesn't fall within any row, return -1.

Returns:
The row that contains y0, or -1.
See Also:
getRowHeight(int), updateLayoutState()

convertRowToY

protected int convertRowToY(int row)
Return the JList relative Y coordinate of the origin of the specified row or -1 if row isn't valid.

Returns:
The Y coordinate of the origin of row, or -1.
See Also:
getRowHeight(int), updateLayoutState()

maybeUpdateLayoutState

protected void maybeUpdateLayoutState()
If updateLayoutStateNeeded is non zero, call updateLayoutState() and reset updateLayoutStateNeeded. This method should be called by methods before doing any computation based on the geometry of the list. For example it's the first call in paint() and getPreferredSize().

See Also:
updateLayoutState()

updateLayoutState

protected void updateLayoutState()
Recompute the value of cellHeight or cellHeights based and cellWidth, based on the current font and the current values of fixedCellWidth, fixedCellHeight, and prototypeCellValue.

See Also:
maybeUpdateLayoutState()

createMouseInputListener

protected MouseInputListener createMouseInputListener()
Creates a delegate that implements MouseInputListener. The delegate is added to the corresponding java.awt.Component listener lists at installUI() time. Subclasses can override this method to return a custom MouseInputListener, e.g.
 class MyListUI extends BasicListUI {
    protected MouseInputListener createMouseInputListener() {
        return new MyMouseInputHandler();
    }
    public class MyMouseInputHandler extends MouseInputHandler {
        public void mouseMoved(MouseEvent e) {
            // do some extra work when the mouse moves
            super.mouseMoved(e);
        }
    }
 }
 

See Also:
BasicListUI.MouseInputHandler, installUI(javax.swing.JComponent)

createFocusListener

protected FocusListener createFocusListener()

createListSelectionListener

protected ListSelectionListener createListSelectionListener()
Creates an instance of ListSelectionHandler that's added to the JLists by selectionModel as needed. Subclasses can override this method to return a custom ListSelectionListener, e.g.
 class MyListUI extends BasicListUI {
    protected ListSelectionListener createListSelectionListener() {
        return new MySelectionListener();
    }
    public class MySelectionListener extends ListSelectionHandler {
        public void valueChanged(ListSelectionEvent e) {
            // do some extra work when the selection changes
            super.valueChange(e);
        }
    }
 }
 

See Also:
BasicListUI.ListSelectionHandler, installUI(javax.swing.JComponent)

createListDataListener

protected ListDataListener createListDataListener()
Creates an instance of ListDataListener that's added to the JLists by model as needed. Subclasses can override this method to return a custom ListDataListener, e.g.
 class MyListUI extends BasicListUI {
    protected ListDataListener createListDataListener() {
        return new MyListDataListener();
    }
    public class MyListDataListener extends ListDataHandler {
        public void contentsChanged(ListDataEvent e) {
            // do some extra work when the models contents change
            super.contentsChange(e);
        }
    }
 }
 

See Also:
ListDataListener, JList.getModel(), installUI(javax.swing.JComponent)

createPropertyChangeListener

protected PropertyChangeListener createPropertyChangeListener()
Creates an instance of PropertyChangeHandler that's added to the JList by installUI(). Subclasses can override this method to return a custom PropertyChangeListener, e.g.
 class MyListUI extends BasicListUI {
    protected PropertyChangeListener createPropertyChangeListener() {
        return new MyPropertyChangeListener();
    }
    public class MyPropertyChangeListener extends PropertyChangeHandler {
        public void propertyChange(PropertyChangeEvent e) {
            if (e.getPropertyName().equals("model")) {
                // do some extra work when the model changes
            }
            super.propertyChange(e);
        }
    }
 }
 

See Also:
PropertyChangeListener, installUI(javax.swing.JComponent)

Java™ Platform
Standard Ed. 6

Submit a bug or feature
For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2006 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.