jcombobox.java

gcc的组建

    PopupMenuEvent e = new PopupMenuEvent(this);
    for(int i = 0; i < listeners.length; i++)
      listeners[i].popupMenuWillBecomeInvisible(e);
  }

  /**
   * Fires a popupMenuWillBecomeVisible() event to all 
   * <code>PopupMenuListeners</code>.
   *
   * Note: This method is intended for use by plaf classes only.
   */
  public void firePopupMenuWillBecomeVisible()
  {
    PopupMenuListener[] listeners = getPopupMenuListeners();
    PopupMenuEvent e = new PopupMenuEvent(this);
    for(int i = 0; i < listeners.length; i++)
      listeners[i].popupMenuWillBecomeVisible(e);
  }

  /**
   * This method is invoked whenever selected item changes in the combo box's
   * data model. It fires ItemEvent and ActionEvent to all registered
   * ComboBox's ItemListeners and ActionListeners respectively, indicating
   * the change.
   */
  protected void selectedItemChanged()
  {
    // Fire ItemEvent to indicated that previously selected item is now
    // deselected        
    if (selectedItemReminder != null)
      fireItemStateChanged(new ItemEvent(this, ItemEvent.ITEM_STATE_CHANGED,
                                         selectedItemReminder,
                                         ItemEvent.DESELECTED));

    // Fire ItemEvent to indicate that new item is selected    
    Object newSelection = getSelectedItem();
    if (newSelection != null)
      fireItemStateChanged(new ItemEvent(this, ItemEvent.ITEM_STATE_CHANGED,
                                         newSelection, ItemEvent.SELECTED));

    // Fire Action Event to JComboBox's registered listeners					 				 
    fireActionEvent();

    selectedItemReminder = newSelection;
  }

  /**
   * Returns Object array of size 1 containing currently selected element in
   * the JComboBox.
   *
   * @return Object[] Object array of size 1 containing currently selected
   *         element in the JComboBox.
   */
  public Object[] getSelectedObjects()
  {
    return new Object[] { getSelectedItem() };
  }

  /**
   * This method handles actionEvents fired by the ComboBoxEditor. It changes
   * this JComboBox's selection to the new value currently in the editor and
   * hides list of combo box items.
   *
   * @param e the ActionEvent
   */
  public void actionPerformed(ActionEvent e)
  {
    setSelectedItem(((ComboBoxEditor) e.getSource()).getItem());
    setPopupVisible(false);
  }

  /**
   * This method selects item in this combo box that matches specified
   * specified keyChar and returns true if such item is found. Otherwise
   * false is returned.
   *
   * @param keyChar character indicating which item in the combo box should be
   *        selected.
   *
   * @return boolean true if item corresponding to the specified keyChar
   *         exists in the combo box. Otherwise false is returned.
   */
  public boolean selectWithKeyChar(char keyChar)
  {
    // FIXME: Need to implement
    return false;
  }

  /**
   * The part of implementation of ListDataListener interface. This method is
   * invoked when some items where added to the JComboBox's data model.
   *
   * @param event ListDataEvent describing the change
   */
  public void intervalAdded(ListDataEvent event)
  {
    // FIXME: Need to implement
    repaint();
  }

  /**
   * The part of implementation of ListDataListener interface. This method is
   * invoked when some items where removed from the JComboBox's data model.
   *
   * @param event ListDataEvent describing the change.
   */
  public void intervalRemoved(ListDataEvent event)
  {
    // FIXME: Need to implement
    repaint();
  }

  /**
   * The part of implementation of ListDataListener interface. This method is
   * invoked when contents of the JComboBox's  data model changed.
   *
   * @param event ListDataEvent describing the change
   */
  public void contentsChanged(ListDataEvent event)
  {
    // if first and last index of the given ListDataEvent are both -1,
    // then it indicates that selected item in the combo box data model
    // have changed. 
    if (event.getIndex0() == -1 && event.getIndex1() == -1)
      selectedItemChanged();
  }

  /**
   * This method disables or enables JComboBox. If the JComboBox is enabled,
   * then user is able to make item choice, otherwise if JComboBox is
   * disabled then user is not able to make a selection.
   *
   * @param enabled if 'enabled' is true then enable JComboBox and disable it
   */
  public void setEnabled(boolean enabled)
  {
    boolean oldEnabled = super.isEnabled();
    if (enabled != oldEnabled)
      {
        super.setEnabled(enabled);
        firePropertyChange("enabled", oldEnabled, enabled);
      }
  }

  /**
   * This method initializes specified ComboBoxEditor to display given item.
   *
   * @param anEditor ComboBoxEditor to initialize
   * @param anItem Item that should displayed in the specified editor
   */
  public void configureEditor(ComboBoxEditor anEditor, Object anItem)
  {
    anEditor.setItem(anItem);
  }

  /**
   * This method hides  combo box's popup whenever TAB key is pressed.
   *
   * @param e The KeyEvent indicating which key was pressed.
   */
  public void processKeyEvent(KeyEvent e)
  {
    if (e.getKeyCode() == KeyEvent.VK_TAB)
      setPopupVisible(false);
    else if (keySelectionManager != null)
      {
        int i = keySelectionManager.selectionForKey(e.getKeyChar(),
                                                    getModel());
        if (i >= 0)
          setSelectedIndex(i);
        else
          super.processKeyEvent(e);
      }
    else
      super.processKeyEvent(e);
  }

  /**
   * setKeySelectionManager
   *
   * @param aManager
   */
  public void setKeySelectionManager(KeySelectionManager aManager)
  {
    keySelectionManager = aManager;
  }

  /**
   * getKeySelectionManager
   *
   * @return JComboBox.KeySelectionManager
   */
  public KeySelectionManager getKeySelectionManager()
  {
    return null;
  }

  /**
   * This method returns number of elements in this JComboBox
   *
   * @return int number of elements in this JComboBox
   */
  public int getItemCount()
  {
    return dataModel.getSize();
  }

  /**
   * Returns elements located in the combo box at the given index.
   *
   * @param index index specifying location of the component to  return.
   *
   * @return component in the combo box that is located in  the given index.
   */
  public Object getItemAt(int index)
  {
    return dataModel.getElementAt(index);
  }

  /**
   * createDefaultKeySelectionManager
   *
   * @return KeySelectionManager
   */
  protected KeySelectionManager createDefaultKeySelectionManager()
  {
    return null;
  }

  /**
   * A string that describes this JComboBox. Normally only used for debugging.
   *
   * @return A string describing this JComboBox
   */
  protected String paramString()
  {
    return "JComboBox";
  }

  public AccessibleContext getAccessibleContext()
  {
    if (accessibleContext == null)
      accessibleContext = new AccessibleJComboBox();

    return accessibleContext;
  }

  /**
   * This methods adds specified ActionListener to this JComboBox.
   *
   * @param listener to add
   */
  public void addActionListener(ActionListener listener)
  {
    listenerList.add(ActionListener.class, listener);
  }

  /**
   * This method removes specified ActionListener from this JComboBox.
   *
   * @param listener ActionListener
   */
  public void removeActionListener(ActionListener listener)
  {
    listenerList.remove(ActionListener.class, listener);
  }

  /**
   * This method returns array of ActionListeners that are registered with
   * this JComboBox.
   *
   * @since 1.4
   */
  public ActionListener[] getActionListeners()
  {
    return (ActionListener[]) getListeners(ActionListener.class);
  }

  /**
   * This method registers given ItemListener with this JComboBox
   *
   * @param listener to remove
   */
  public void addItemListener(ItemListener listener)
  {
    listenerList.add(ItemListener.class, listener);
  }

  /**
   * This method unregisters given ItemListener from this JComboBox
   *
   * @param listener to remove
   */
  public void removeItemListener(ItemListener listener)
  {
    listenerList.remove(ItemListener.class, listener);
  }

  /**
   * This method returns array of ItemListeners that are registered with this
   * JComboBox.
   *
   * @since 1.4
   */
  public ItemListener[] getItemListeners()
  {
    return (ItemListener[]) getListeners(ItemListener.class);
  }

  /**
   * Adds PopupMenuListener to combo box to listen to the events fired by the
   * combo box's popup menu containing its list of items
   *
   * @param listener to add
   */
  public void addPopupMenuListener(PopupMenuListener listener)
  {
    listenerList.add(PopupMenuListener.class, listener);
  }

  /**
   * Removes PopupMenuListener to combo box to listen to the events fired by
   * the combo box's popup menu containing its list of items
   *
   * @param listener to add
   */
  public void removePopupMenuListener(PopupMenuListener listener)
  {
    listenerList.remove(PopupMenuListener.class, listener);
  }

  /**
   * Returns array of PopupMenuListeners that are registered with  combo box.
   */
  public PopupMenuListener[] getPopupMenuListeners()
  {
    return (PopupMenuListener[]) getListeners(PopupMenuListener.class);
  }

  /**
   * Accessibility support for <code>JComboBox</code>.
   */
  protected class AccessibleJComboBox extends AccessibleJComponent
    implements AccessibleAction, AccessibleSelection
  {
    private static final long serialVersionUID = 8217828307256675666L;

    protected AccessibleJComboBox()
    {
      // Nothing to do here.
    }

    public int getAccessibleChildrenCount()
    {
      return 0;
    }

    public Accessible getAccessibleChild(int value0)
    {
      return null;
    }

    public AccessibleSelection getAccessibleSelection()
    {
      return null;
    }

    public Accessible getAccessibleSelection(int value0)
    {
      return null;
    }

    public boolean isAccessibleChildSelected(int value0)
    {
      return false;
    }

    public AccessibleRole getAccessibleRole()
    {
      return AccessibleRole.COMBO_BOX;
    }

    public AccessibleAction getAccessibleAction()
    {
      return null;
    }

    public String getAccessibleActionDescription(int value0)
    {
      return null;
    }

    public int getAccessibleActionCount()
    {
      return 0;
    }

    public boolean doAccessibleAction(int value0)
    {
      return false;
    }

    public int getAccessibleSelectionCount()
    {
      return 0;
    }

    public void addAccessibleSelection(int value0)
    {
      // TODO: Implement this properly.
    }

    public void removeAccessibleSelection(int value0)
    {
      // TODO: Implement this properly.
    }

    public void clearAccessibleSelection()
    {
      // TODO: Implement this properly.
    }

    public void selectAllAccessibleSelection()
    {
      // TODO: Implement this properly.
    }
  }
}