Module java.desktop

Package javax.swing.plaf.basic

Class BasicListUI

java.lang.Object

javax.swing.plaf.ComponentUI

javax.swing.plaf.ListUI

javax.swing.plaf.basic.BasicListUI

Direct Known Subclasses:

SynthListUI

public class BasicListUI
extends ListUI

An extensible implementation of ListUI.

BasicListUI instances cannot be shared between multiple lists.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	BasicListUI.FocusHandler	This class should be treated as a "protected" inner class.
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

Fields

Modifier and Type	Field	Description
protected int	cellHeight	The height of cell.
protected int[]	cellHeights	The array of cells' height
protected static final int	cellRendererChanged	The bit relates to cell renderer changed property.
protected int	cellWidth	The width of cell.
protected static final int	fixedCellHeightChanged	The bit relates to fixed cell height changed property.
protected static final int	fixedCellWidthChanged	The bit relates to fixed cell width changed property.
protected FocusListener	focusListener	FocusListener that attached to JList.
protected static final int	fontChanged	The bit relates to font changed property.
protected JList<Object>	list	The instance of JList.
protected ListDataListener	listDataListener	ListDataListener that attached to JList.
protected ListSelectionListener	listSelectionListener	ListSelectionListener that attached to JList.
protected static final int	modelChanged	The bit relates to model changed property.
protected MouseInputListener	mouseInputListener	MouseInputListener that attached to JList.
protected PropertyChangeListener	propertyChangeListener	PropertyChangeListener that attached to JList.
protected static final int	prototypeCellValueChanged	The bit relates to prototype cell value changed property.
protected CellRendererPane	rendererPane	The instance of CellRendererPane.
protected static final int	selectionModelChanged	The bit relates to selection model changed property.
protected int	updateLayoutStateNeeded	The value represents changes to JList model.

Constructor Summary

Constructors

Constructor	Description
BasicListUI()	Constructs a BasicListUI.

Method Summary

Modifier and Type	Method	Description
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()	Returns an instance of FocusListener.
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()	Initializes list properties such as font, foreground, and background, and adds the CellRendererPane.
protected void	installKeyboardActions()	Registers the keyboard bindings on the JList that the BasicListUI is associated with.
protected void	installListeners()	Creates and installs 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<Object> cellRenderer, ListModel<Object> 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()	Sets the list properties that have not been explicitly overridden to null.
protected void	uninstallKeyboardActions()	Unregisters keyboard actions installed from installKeyboardActions.
protected void	uninstallListeners()	Removes the listeners from 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 declared in class javax.swing.plaf.ComponentUI

contains, getAccessibleChild, getAccessibleChildrenCount, getMaximumSize, getMinimumSize, update

Methods declared in class java.lang.Object

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

Field Details

list

protected JList<Object> list

The instance of JList.

rendererPane

protected CellRendererPane rendererPane

The instance of CellRendererPane.

focusListener

protected FocusListener focusListener

FocusListener that attached to JList.

mouseInputListener

protected MouseInputListener mouseInputListener

MouseInputListener that attached to JList.

listSelectionListener

protected ListSelectionListener listSelectionListener

ListSelectionListener that attached to JList.

listDataListener

protected ListDataListener listDataListener

ListDataListener that attached to JList.

propertyChangeListener

protected PropertyChangeListener propertyChangeListener

PropertyChangeListener that attached to JList.

cellHeights

protected int[] cellHeights

The array of cells' height

cellHeight

protected int cellHeight

The height of cell.

cellWidth

protected int cellWidth

The width of cell.

updateLayoutStateNeeded

protected int updateLayoutStateNeeded

The value represents changes to JList model.

modelChanged

protected static final int modelChanged

The bit relates to model changed property.

See Also:

• Constant Field Values

selectionModelChanged

protected static final int selectionModelChanged

The bit relates to selection model changed property.

See Also:

• Constant Field Values

fontChanged

protected static final int fontChanged

The bit relates to font changed property.

See Also:

• Constant Field Values

fixedCellWidthChanged

protected static final int fixedCellWidthChanged

The bit relates to fixed cell width changed property.

See Also:

• Constant Field Values

fixedCellHeightChanged

protected static final int fixedCellHeightChanged

The bit relates to fixed cell height changed property.

See Also:

• Constant Field Values

prototypeCellValueChanged

protected static final int prototypeCellValueChanged

The bit relates to prototype cell value changed property.

See Also:

• Constant Field Values

cellRendererChanged

protected static final int cellRendererChanged

The bit relates to cell renderer changed property.

See Also:

• Constant Field Values

Constructor Details

BasicListUI

public BasicListUI()

Constructs a BasicListUI.

Method Details

paintCell

protected void paintCell(Graphics g,
 int row,
 Rectangle rowBounds,
 ListCellRenderer<Object> cellRenderer,
 ListModel<Object> 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().

Parameters:

g - an instance of Graphics

row - a row

rowBounds - a bounding rectangle to render to

cellRenderer - a list of ListCellRenderer

dataModel - a list model

selModel - a selection model

leadIndex - a lead index

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<java.lang.Object>, javax.swing.ListModel<java.lang.Object>, 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.

Describes the preferred size for each layout orientation

Layout Orientation	Preferred 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()

Creates and installs 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()

Removes the listeners from 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()

Initializes list properties such as font, foreground, and background, and adds 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()

Sets the list properties that have not 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.

Parameters:

list - a component

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.

Parameters:

row - a row

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.

Parameters:

y0 - a relative Y coordinate

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.

Parameters:

row - a row

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);
        }
    }
 }
 

Returns:

an instance of MouseInputListener

See Also:

• BasicListUI.MouseInputHandler
• installUI(javax.swing.JComponent)

createFocusListener

protected FocusListener createFocusListener()

Returns an instance of FocusListener.

Returns:

an instance of FocusListener

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);
        }
    }
 }
 

Returns:

an instance of ListSelectionHandler

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);
        }
    }
 }
 

Returns:

an instance of ListDataListener

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);
        }
    }
 }
 

Returns:

an instance of PropertyChangeHandler

See Also:

• PropertyChangeListener
• installUI(javax.swing.JComponent)