basiccombopopup.java

java jdk 1.4的源码

     * <code>ComboBoxModel</code>. If this method returns null then
     * it will not be added to the combo box model.
     *
     * @return an instance of a <code>ListDataListener</code> or null
     */
    protected ListDataListener createListDataListener() {
        return null;
    }

    /**
     * Creates a mouse listener that watches for mouse events in
     * the popup's list. If this method returns null then it will
     * not be added to the combo box.
     *
     * @return an instance of a <code>MouseListener</code> or null
     */
    protected MouseListener createListMouseListener() {
        return new ListMouseHandler();
    }

    /**
     * Creates a mouse motion listener that watches for mouse motion 
     * events in the popup's list. If this method returns null then it will
     * not be added to the combo box.
     *
     * @return an instance of a <code>MouseMotionListener</code> or null
     */
    protected MouseMotionListener createListMouseMotionListener() {
        return new ListMouseMotionHandler();
    }

    /**
     * Creates a <code>PropertyChangeListener</code> which will be added to
     * the combo box. If this method returns null then it will not
     * be added to the combo box.
     * 
     * @return an instance of a <code>PropertyChangeListener</code> or null
     */
    protected PropertyChangeListener createPropertyChangeListener() {
        return new PropertyChangeHandler();
    }

    /**
     * Creates an <code>ItemListener</code> which will be added to the 
     * combo box. If this method returns null then it will not 
     * be added to the combo box.
     * <p>
     * Subclasses may override this method to return instances of their own
     * ItemEvent handlers.
     *
     * @return an instance of an <code>ItemListener</code> or null
     */
    protected ItemListener createItemListener() {
        return new ItemHandler();
    }

    /**
     * Creates the JList used in the popup to display 
     * the items in the combo box model. This method is called when the UI class
     * is created.
     *
     * @return a <code>JList</code> used to display the combo box items
     */
    protected JList createList() {
	return new JList( comboBox.getModel() ) {
            public void processMouseEvent(MouseEvent e)  {
                if (e.isControlDown())  {
                    // Fix for 4234053. Filter out the Control Key from the list. 
                    // ie., don't allow CTRL key deselection.
                    e = new MouseEvent((Component)e.getSource(), e.getID(), e.getWhen(), 
                                   e.getModifiers() ^ InputEvent.CTRL_MASK,
                                   e.getX(), e.getY(), e.getClickCount(), e.isPopupTrigger());
                }
                super.processMouseEvent(e);
            }
        };
    }

    /**
     * Configures the list which is used to hold the combo box items in the
     * popup. This method is called when the UI class
     * is created.
     *
     * @see #createList
     */
    protected void configureList() {
        list.setFont( comboBox.getFont() );
        list.setForeground( comboBox.getForeground() );
        list.setBackground( comboBox.getBackground() );
        list.setSelectionForeground( UIManager.getColor( "ComboBox.selectionForeground" ) );
        list.setSelectionBackground( UIManager.getColor( "ComboBox.selectionBackground" ) );
        list.setBorder( null );
        list.setCellRenderer( comboBox.getRenderer() );
        list.setFocusable( false );
        list.setSelectionMode( ListSelectionModel.SINGLE_SELECTION );
        setListSelection( comboBox.getSelectedIndex() );
        installListListeners();
    }

    /**
     * Adds the listeners to the list control.
     */
    protected void installListListeners() {
        if ((listMouseListener = createListMouseListener()) != null) {
	    list.addMouseListener( listMouseListener );
	}
	if ((listMouseMotionListener = createListMouseMotionListener()) != null) {
	    list.addMouseMotionListener( listMouseMotionListener );
	}
	if ((listSelectionListener = createListSelectionListener()) != null) {
	    list.addListSelectionListener( listSelectionListener );
	}
    }

    void uninstallListListeners() {
	if (listMouseListener != null) {
	    list.removeMouseListener(listMouseListener);
	    listMouseListener = null;
	}
	if (listMouseMotionListener != null) {
	    list.removeMouseMotionListener(listMouseMotionListener);
	    listMouseMotionListener = null;
	}
	if (listSelectionListener != null) {
	    list.removeListSelectionListener(listSelectionListener);
	    listSelectionListener = null;
	}
    }

    /**
     * Creates the scroll pane which houses the scrollable list.
     */
    protected JScrollPane createScroller() {
	return new JScrollPane( list, 
				ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
				ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER );
    }

    /**
     * Configures the scrollable portion which holds the list within 
     * the combo box popup. This method is called when the UI class
     * is created.
     */
    protected void configureScroller() {
        scroller.setFocusable( false );
        scroller.getVerticalScrollBar().setFocusable( false );
        scroller.setBorder( null );
    }

    /**
     * Configures the popup portion of the combo box. This method is called
     * when the UI class is created.
     */
    protected void configurePopup() {
        setLayout( new BoxLayout( this, BoxLayout.Y_AXIS ) );
        setBorderPainted( true );
        setBorder( BorderFactory.createLineBorder( Color.black ) );
        setOpaque( false );
        add( scroller );
        setDoubleBuffered( true );
        setFocusable( false );
    }

    /**
     * This method adds the necessary listeners to the JComboBox.
     */
    protected void installComboBoxListeners() {
        if ((propertyChangeListener = createPropertyChangeListener()) != null) {
	    comboBox.addPropertyChangeListener(propertyChangeListener);
	}
	if ((itemListener = createItemListener()) != null) {
	    comboBox.addItemListener(itemListener);
	}
	installComboBoxModelListeners(comboBox.getModel());
    }

    /** 
     * Installs the listeners on the combo box model. Any listeners installed
     * on the combo box model should be removed in 
     * <code>uninstallComboBoxModelListeners</code>.
     *
     * @param model The combo box model to install listeners
     * @see #uninstallComboBoxModelListeners
     */
    protected void installComboBoxModelListeners( ComboBoxModel model ) {
	if (model != null && (listDataListener = createListDataListener()) != null) {
	    model.addListDataListener(listDataListener);
	}
    }

    protected void installKeyboardActions() {
        
        /* XXX - shouldn't call this method. take it out for testing.
        ActionListener action = new ActionListener() {
            public void actionPerformed(ActionEvent e){
            }
        };

        comboBox.registerKeyboardAction( action,
                                         KeyStroke.getKeyStroke( KeyEvent.VK_ENTER, 0 ),
                                         JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT ); */
        
    }

    //
    // end Initialization routines
    //=================================================================


    //===================================================================
    // begin Event Listenters
    //

    /**
     * A listener to be registered upon the combo box
     * (<em>not</em> its popup menu)
     * to handle mouse events
     * that affect the state of the popup menu.
     * The main purpose of this listener is to make the popup menu
     * appear and disappear.
     * This listener also helps
     * with click-and-drag scenarios by setting the selection if the mouse was
     * released over the list during a drag.
     *
     * <p>
     * <strong>Warning:</strong>
     * We recommend that you <em>not</em> 
     * create subclasses of this class.
     * If you absolutely must create a subclass,
     * be sure to invoke the superclass
     * version of each method.
     *
     * @see BasicComboPopup#createMouseListener
     */
    protected class InvocationMouseHandler extends MouseAdapter {
	/**
	 * Responds to mouse-pressed events on the combo box.
	 *
	 * @param e the mouse-press event to be handled
	 */
        public void mousePressed( MouseEvent e ) {
            if (!SwingUtilities.isLeftMouseButton(e) || !comboBox.isEnabled())
                return;

	    if ( comboBox.isEditable() ) {
                Component comp = comboBox.getEditor().getEditorComponent();
                if ((!(comp instanceof JComponent)) || ((JComponent)comp).isRequestFocusEnabled()) {
		    comp.requestFocus();
                }
	    }
	    else if (comboBox.isRequestFocusEnabled()) {
		comboBox.requestFocus();
	    }
	    togglePopup();
        }

	/**
	 * Responds to the user terminating
	 * a click or drag that began on the combo box.
	 *
	 * @param e the mouse-release event to be handled
	 */
        public void mouseReleased( MouseEvent e ) {
	    Component source = (Component)e.getSource();
            Dimension size = source.getSize();
            Rectangle bounds = new Rectangle( 0, 0, size.width - 1, size.height - 1 );
            if ( !bounds.contains( e.getPoint() ) ) {
                MouseEvent newEvent = convertMouseEvent( e );
                Point location = newEvent.getPoint();
                Rectangle r = new Rectangle();
		list.computeVisibleRect( r );
		if ( r.contains( location ) ) {
		    comboBox.setSelectedIndex( list.getSelectedIndex() );
                }
		comboBox.setPopupVisible(false);
            }
            hasEntered = false;
            stopAutoScrolling();
        }
    }

    /**
     * This listener watches for dragging and updates the current selection in the
     * list if it is dragging over the list.
     */
    protected class InvocationMouseMotionHandler extends MouseMotionAdapter {
        public void mouseDragged( MouseEvent e ) {
            if ( isVisible() ) {
                MouseEvent newEvent = convertMouseEvent( e );
                Rectangle r = new Rectangle();
                list.computeVisibleRect( r );

                if ( newEvent.getPoint().y >= r.y && newEvent.getPoint().y <= r.y + r.height - 1 ) {
                    hasEntered = true;
                    if ( isAutoScrolling ) {
                        stopAutoScrolling();
                    }
                    Point location = newEvent.getPoint();
                    if ( r.contains( location ) ) {
                        updateListBoxSelectionForEvent( newEvent, false );
                    }
                }
                else {
                    if ( hasEntered ) {
                        int directionToScroll = newEvent.getPoint().y < r.y ? SCROLL_UP : SCROLL_DOWN;
                        if ( isAutoScrolling && scrollDirection != directionToScroll ) {
                            stopAutoScrolling();
                            startAutoScrolling( directionToScroll );
                        }
                        else if ( !isAutoScrolling ) {
                            startAutoScrolling( directionToScroll );
                        }
                    }
                    else {
                        if ( e.getPoint().y < 0 ) {
                            hasEntered = true;
                            startAutoScrolling( SCROLL_UP );
                        }
                    }
                }
            }
        }
    }

    /**
     * As of Java 2 platform v 1.4, this class is now obsolete and is only included for
     * backwards API compatibility. Do not instantiate or subclass.
     * <p>
     * All the functionality of this class has been included in 
     * BasicComboBoxUI ActionMap/InputMap methods.
     */
    public class InvocationKeyHandler extends KeyAdapter {
	public void keyReleased( KeyEvent e ) {}
    }
    
    /**
     * As of Java 2 platform v 1.4, this class is now obsolete, doesn't do anything, and
     * is only included for backwards API compatibility. Do not call or 
     * override.
     */
    protected class ListSelectionHandler implements ListSelectionListener {
        public void valueChanged( ListSelectionEvent e ) {}
    }

    /**
     * As of 1.4, this class is now obsolete, doesn't do anything, and
     * is only included for backwards API compatibility. Do not call or 
     * override. 
     * <p>
     * The functionality has been migrated into <code>ItemHandler</code>.
     *
     * @see #createItemListener
     */
    public class ListDataHandler implements ListDataListener {
        public void contentsChanged( ListDataEvent e ) {}

        public void intervalAdded( ListDataEvent e ) {
        }

        public void intervalRemoved( ListDataEvent e ) {
        }
    }

    /**
     * This listener hides the popup when the mouse is released in the list.
     */
    protected class ListMouseHandler extends MouseAdapter {
        public void mousePressed( MouseEvent e ) {
        }
        public void mouseReleased(MouseEvent anEvent) {
            comboBox.setSelectedIndex( list.getSelectedIndex() );
	    comboBox.setPopupVisible(false);
            // workaround for cancelling an edited item (bug 4530953)
            if (comboBox.isEditable() && comboBox.getEditor() != null) {
                comboBox.configureEditor(comboBox.getEditor(), 
                                         comboBox.getSelectedItem()); 
            }
        }