basiclistui.java

gcc的组建

  }

  /**
   * Creates a new BasicListUI object.
   */
  public BasicListUI()
  {
    updateLayoutStateNeeded = 1;
    rendererPane = new CellRendererPane();
  }

  /**
   * Installs various default settings (mostly colors) from the {@link
   * UIDefaults} into the {@link JList}
   *
   * @see #uninstallDefaults
   */
  protected void installDefaults()
  {
    LookAndFeel.installColorsAndFont(list, "List.background",
                                     "List.foreground", "List.font");
    list.setSelectionForeground(UIManager.getColor("List.selectionForeground"));
    list.setSelectionBackground(UIManager.getColor("List.selectionBackground"));
    list.setOpaque(true);
  }

  /**
   * Resets to <code>null</code> those defaults which were installed in 
   * {@link #installDefaults}
   */
  protected void uninstallDefaults()
  {
    list.setForeground(null);
    list.setBackground(null);
    list.setSelectionForeground(null);
    list.setSelectionBackground(null);
  }

  /**
   * Attaches all the listeners we have in the UI class to the {@link
   * JList}, its model and its selection model.
   *
   * @see #uninstallListeners
   */
  protected void installListeners()
  {
    if (focusListener == null)
      focusListener = createFocusListener();
    list.addFocusListener(focusListener);
    if (listDataListener == null)
      listDataListener = createListDataListener();
    list.getModel().addListDataListener(listDataListener);
    if (listSelectionListener == null)
      listSelectionListener = createListSelectionListener();
    list.addListSelectionListener(listSelectionListener);
    if (mouseInputListener == null)
      mouseInputListener = createMouseInputListener();
    list.addMouseListener(mouseInputListener);
    list.addMouseMotionListener(mouseInputListener);
    if (propertyChangeListener == null)
      propertyChangeListener = createPropertyChangeListener();
    list.addPropertyChangeListener(propertyChangeListener);

    // FIXME: Are these two really needed? At least they are not documented.
    //keyListener = new KeyHandler();
    componentListener = new ComponentHandler();
    list.addComponentListener(componentListener);
    //list.addKeyListener(keyListener);
  }

  /**
   * Detaches all the listeners we attached in {@link #installListeners}.
   */
  protected void uninstallListeners()
  {
    list.removeFocusListener(focusListener);
    list.getModel().removeListDataListener(listDataListener);
    list.removeListSelectionListener(listSelectionListener);
    list.removeMouseListener(mouseInputListener);
    //list.removeKeyListener(keyListener);
    list.removeMouseMotionListener(mouseInputListener);
    list.removePropertyChangeListener(propertyChangeListener);
  }
  
  /**
   * Installs keyboard actions for this UI in the {@link JList}.
   */
  protected void installKeyboardActions()
  {
    InputMap focusInputMap = (InputMap) UIManager.get("List.focusInputMap");
    InputMapUIResource parentInputMap = new InputMapUIResource();
    // FIXME: The JDK uses a LazyActionMap for parentActionMap
    ActionMap parentActionMap = new ActionMapUIResource();
    action = new ListAction();
    Object keys[] = focusInputMap.allKeys();
    // Register key bindings in the UI InputMap-ActionMap pair
    for (int i = 0; i < keys.length; i++)
      {
        KeyStroke stroke = (KeyStroke)keys[i];
        String actionString = (String) focusInputMap.get(stroke);
        parentInputMap.put(KeyStroke.getKeyStroke(stroke.getKeyCode(),
                                                  stroke.getModifiers()),
                           actionString);

        parentActionMap.put (actionString, 
                             new ActionListenerProxy(action, actionString));
      }
    // Register the new InputMap-ActionMap as the parents of the list's
    // InputMap and ActionMap
    parentInputMap.setParent(list.getInputMap().getParent());
    parentActionMap.setParent(list.getActionMap().getParent());
    list.getInputMap().setParent(parentInputMap);
    list.getActionMap().setParent(parentActionMap);
  }

  /**
   * Uninstalls keyboard actions for this UI in the {@link JList}.
   */
  protected void uninstallKeyboardActions()
  {
    // TODO: Implement this properly.
  }

  /**
   * Installs the various aspects of the UI in the {@link JList}. In
   * particular, calls {@link #installDefaults}, {@link #installListeners}
   * and {@link #installKeyboardActions}. Also saves a reference to the
   * provided component, cast to a {@link JList}.
   *
   * @param c The {@link JList} to install the UI into
   */
  public void installUI(final JComponent c)
  {
    super.installUI(c);
    list = (JList) c;
    installDefaults();
    installListeners();
    installKeyboardActions();
    maybeUpdateLayoutState();
  }

  /**
   * Uninstalls all the aspects of the UI which were installed in {@link
   * #installUI}. When finished uninstalling, drops the saved reference to
   * the {@link JList}.
   *
   * @param c Ignored; the UI is uninstalled from the {@link JList}
   * reference saved during the call to {@link #installUI}
   */
  public void uninstallUI(final JComponent c)
  {
    uninstallKeyboardActions();
    uninstallListeners();
    uninstallDefaults();
    list = null;
  }

  /**
   * Gets the size this list would prefer to assume. This is calculated by
   * calling {@link #getCellBounds} over the entire list.
   *
   * @param c Ignored; uses the saved {@link JList} reference 
   *
   * @return DOCUMENT ME!
   */
  public Dimension getPreferredSize(JComponent c)
  {
    int size = list.getModel().getSize();
    if (size == 0)
      return new Dimension(0, 0);
    int visibleRows = list.getVisibleRowCount();
    int layoutOrientation = list.getLayoutOrientation();
    Rectangle bounds = getCellBounds(list, 0, list.getModel().getSize() - 1);
    Dimension retVal = bounds.getSize();
    Component parent = list.getParent();
    if ((visibleRows == -1) && (parent instanceof JViewport))
      {
        JViewport viewport = (JViewport) parent;

        if (layoutOrientation == JList.HORIZONTAL_WRAP)
          {
            int h = viewport.getSize().height;
            int cellsPerCol = h / cellHeight;
            int w = size / cellsPerCol * cellWidth;
            retVal = new Dimension(w, h);
          }
        else if (layoutOrientation == JList.VERTICAL_WRAP)
          {
            int w = viewport.getSize().width;
            int cellsPerRow = Math.max(w / cellWidth, 1);
            int h = size / cellsPerRow * cellHeight;
            retVal = new Dimension(w, h);
          }
      }
    return retVal;
  }

  /**
   * Paints a single cell in the list.
   *
   * @param g The graphics context to paint in
   * @param row The row number to paint
   * @param bounds The bounds of the cell to paint, assuming a coordinate
   * system beginning at <code>(0,0)</code> in the upper left corner of the
   * list
   * @param rend A cell renderer to paint with
   * @param data The data to provide to the cell renderer
   * @param sel A selection model to provide to the cell renderer
   * @param lead The lead selection index of the list
   */
  protected void paintCell(Graphics g, int row, Rectangle bounds,
                 ListCellRenderer rend, ListModel data,
                 ListSelectionModel sel, int lead)
  {
    boolean isSel = list.isSelectedIndex(row);
    boolean hasFocus = (list.getLeadSelectionIndex() == row) && BasicListUI.this.list.hasFocus();
    Component comp = rend.getListCellRendererComponent(list,
                                                       data.getElementAt(row),
                                                       0, isSel, hasFocus);
    rendererPane.paintComponent(g, comp, list, bounds);
  }

  /**
   * Paints the list by repeatedly calling {@link #paintCell} for each visible
   * cell in the list.
   *
   * @param g The graphics context to paint with
   * @param c Ignored; uses the saved {@link JList} reference 
   */
  public void paint(Graphics g, JComponent c)
  {
    int nrows = list.getModel().getSize();
    if (nrows == 0)
      return;

    maybeUpdateLayoutState();
    ListCellRenderer render = list.getCellRenderer();
    ListModel model = list.getModel();
    ListSelectionModel sel = list.getSelectionModel();
    int lead = sel.getLeadSelectionIndex();
    Rectangle clip = g.getClipBounds();

    int startIndex = list.locationToIndex(new Point(clip.x, clip.y));
    int endIndex = list.locationToIndex(new Point(clip.x + clip.width,
                                                  clip.y + clip.height));
    
    for (int row = startIndex; row <= endIndex; ++row)
      {
        Rectangle bounds = getCellBounds(list, row, row);
        if (bounds.intersects(clip))
          paintCell(g, row, bounds, render, model, sel, lead);
      }
  }

  /**
   * Computes the index of a list cell given a point within the list. If the
   * location lies outside the bounds of the list, the greatest index in the
   * list model is returned.
   *
   * @param list the list which on which the computation is based on
   * @param location the coordinates
   *
   * @return the index of the list item that is located at the given
   *         coordinates or <code>-1</code> if the list model is empty
   */
  public int locationToIndex(JList list, Point location)
  {
    int layoutOrientation = list.getLayoutOrientation();
    int index = -1;
    switch (layoutOrientation)
      {
      case JList.VERTICAL:
        index = convertYToRow(location.y);
        break;
      case JList.HORIZONTAL_WRAP:
        // determine visible rows and cells per row
        int visibleRows = list.getVisibleRowCount();
        int cellsPerRow = -1;
        int numberOfItems = list.getModel().getSize();
        Dimension listDim = list.getSize();
        if (visibleRows <= 0)
          {
            try
              {
                cellsPerRow = listDim.width / cellWidth;
              }
            catch (ArithmeticException ex)
              {
                cellsPerRow = 1;
              }
          }
        else
          {
            cellsPerRow = numberOfItems / visibleRows + 1;
          }

        // determine index for the given location
        int cellsPerColumn = numberOfItems / cellsPerRow + 1;
        int gridX = Math.min(location.x / cellWidth, cellsPerRow - 1);
        int gridY = Math.min(location.y / cellHeight, cellsPerColumn);
        index = gridX + gridY * cellsPerRow;
        break;
      case JList.VERTICAL_WRAP:
        // determine visible rows and cells per column
        int visibleRows2 = list.getVisibleRowCount();
        if (visibleRows2 <= 0)
          {
            Dimension listDim2 = list.getSize();
            visibleRows2 = listDim2.height / cellHeight;
          }
        int numberOfItems2 = list.getModel().getSize();
        int cellsPerRow2 = numberOfItems2 / visibleRows2 + 1;

        int gridX2 = Math.min(location.x / cellWidth, cellsPerRow2 - 1);
        int gridY2 = Math.min(location.y / cellHeight, visibleRows2);
        index = gridY2 + gridX2 * visibleRows2;
        break;
      }
    return index;
  }

  public Point indexToLocation(JList list, int index)
  {
    int layoutOrientation = list.getLayoutOrientation();
    Point loc = null;
    switch (layoutOrientation)
      {
      case JList.VERTICAL:
        loc = new Point(0, convertRowToY(index));
        break;
      case JList.HORIZONTAL_WRAP:
        // determine visible rows and cells per row
        int visibleRows = list.getVisibleRowCount();
        int numberOfCellsPerRow = -1;
        if (visibleRows <= 0)
          {
            Dimension listDim = list.getSize();
            numberOfCellsPerRow = Math.max(listDim.width / cellWidth, 1);
          }
        else
          {
            int numberOfItems = list.getModel().getSize();
            numberOfCellsPerRow = numberOfItems / visibleRows + 1;
          }
        // compute coordinates inside the grid
        int gridX = index % numberOfCellsPerRow;
        int gridY = index / numberOfCellsPerRow;
        int locX = gridX * cellWidth;
        int locY = gridY * cellHeight;
        loc = new Point(locX, locY);
        break;
      case JList.VERTICAL_WRAP:
        // determine visible rows and cells per column
        int visibleRows2 = list.getVisibleRowCount();
        if (visibleRows2 <= 0)
          {
            Dimension listDim2 = list.getSize();
            visibleRows2 = listDim2.height / cellHeight;
          }
        // compute coordinates inside the grid
        if (visibleRows2 > 0)
          {
            int gridY2 = index % visibleRows2;
            int gridX2 = index / visibleRows2;
            int locX2 = gridX2 * cellWidth;
            int locY2 = gridY2 * cellHeight;
            loc = new Point(locX2, locY2);
          }
        else
          loc = new Point(0, convertRowToY(index));
        break;
      }
    return loc;
  }

  /**
   * Creates and returns the focus listener for this UI.
   *
   * @return the focus listener for this UI
   */
  protected FocusListener createFocusListener()
  {
    return new FocusHandler();
  }

  /**
   * Creates and returns the list data listener for this UI.
   *
   * @return the list data listener for this UI
   */
  protected ListDataListener createListDataListener()
  {
    return new ListDataHandler();
  }

  /**
   * Creates and returns the list selection listener for this UI.
   *
   * @return the list selection listener for this UI
   */
  protected ListSelectionListener createListSelectionListener()
  {
    return new ListSelectionHandler();
  }

  /**
   * Creates and returns the mouse input listener for this UI.
   *
   * @return the mouse input listener for this UI
   */
  protected MouseInputListener createMouseInputListener()
  {
    return new MouseInputHandler();
  }

  /**
   * Creates and returns the property change listener for this UI.
   *
   * @return the property change listener for this UI
   */
  protected PropertyChangeListener createPropertyChangeListener()
  {
    return new PropertyChangeHandler();
  }

  /**
   * Selects the next list item and force it to be visible.
   */
  protected void selectNextIndex()
  {
    int index = list.getSelectionModel().getLeadSelectionIndex();
    if (index < list.getModel().getSize() - 1)
      {
        index++;
        list.setSelectedIndex(index);
      }
    list.ensureIndexIsVisible(index);
  }

  /**
   * Selects the previous list item and force it to be visible.
   */
  protected void selectPreviousIndex()
  {
    int index = list.getSelectionModel().getLeadSelectionIndex();
    if (index > 0)
      {
        index--;
        list.setSelectedIndex(index);
      }
    list.ensureIndexIsVisible(index);
  }
}