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## javax.swing.plaf.basic
Class BasicListUI

    java.lang.Object
      javax.swing.plaf.ComponentUI
          javax.swing.plaf.ListUI
              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 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()

  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)`

Overview | Package | Class | Use | Tree | Deprecated | Index | Help
| Java™ Platform Standard Ed. 6
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