basiccombopopup.java

JAVA 所有包

        //
        // MouseMotionListener:
        // NOTE: this is added to both the List and ComboBox
        //
        public void mouseMoved(MouseEvent anEvent) {
            if (anEvent.getSource() == list) {
                Point location = anEvent.getPoint();
                Rectangle r = new Rectangle();
                list.computeVisibleRect( r );
                if ( r.contains( location ) ) {
                    updateListBoxSelectionForEvent( anEvent, false );
                }
            }
        }

        public void mouseDragged( MouseEvent e ) {
            if (e.getSource() == list) {
                return;
            }
            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 );
                        }
                    }
                }
            }
        }

        //
        // PropertyChangeListener
        //
        public void propertyChange(PropertyChangeEvent e) {
	    JComboBox comboBox = (JComboBox)e.getSource();
            String propertyName = e.getPropertyName();

            if ( propertyName == "model" ) {
                ComboBoxModel oldModel = (ComboBoxModel)e.getOldValue();
                ComboBoxModel newModel = (ComboBoxModel)e.getNewValue();
		uninstallComboBoxModelListeners(oldModel);
		installComboBoxModelListeners(newModel);

                list.setModel(newModel);

                if ( isVisible() ) {
                    hide();
                }
            }
            else if ( propertyName == "renderer" ) {
                list.setCellRenderer( comboBox.getRenderer() );
                if ( isVisible() ) {
                    hide();
                }
            }
	    else if (propertyName == "componentOrientation") {
                // Pass along the new component orientation
                // to the list and the scroller

                ComponentOrientation o =(ComponentOrientation)e.getNewValue();

                JList list = getList();
                if (list!=null && list.getComponentOrientation()!=o) {
                    list.setComponentOrientation(o);
                }

                if (scroller!=null && scroller.getComponentOrientation()!=o) {
                    scroller.setComponentOrientation(o);
                }

                if (o!=getComponentOrientation()) {
                    setComponentOrientation(o);
                }
            }
	    else if (propertyName == "lightWeightPopupEnabled") {
		setLightWeightPopupEnabled(comboBox.isLightWeightPopupEnabled());
	    }
        }

        //
        // ItemListener
        //
        public void itemStateChanged( ItemEvent e ) {
	    if (e.getStateChange() == ItemEvent.SELECTED) {
		JComboBox comboBox = (JComboBox)e.getSource();
		setListSelection(comboBox.getSelectedIndex());
	    }
	}
    }

    //
    // end Event Listeners
    //=================================================================


    /**
     * Overridden to unconditionally return false.
     */
    public boolean isFocusTraversable() {
        return false;
    }

    //===================================================================
    // begin Autoscroll methods
    //

    /**
     * This protected method is implementation specific and should be private.
     * do not call or override.
     */
    protected void startAutoScrolling( int direction ) {
        // XXX - should be a private method within InvocationMouseMotionHandler
        // if possible.
        if ( isAutoScrolling ) {
            autoscrollTimer.stop();
        }

        isAutoScrolling = true;

        if ( direction == SCROLL_UP ) {
            scrollDirection = SCROLL_UP;
            Point convertedPoint = SwingUtilities.convertPoint( scroller, new Point( 1, 1 ), list );
            int top = list.locationToIndex( convertedPoint );
            list.setSelectedIndex( top );

            autoscrollTimer = new Timer( 100, new AutoScrollActionHandler(
                                             SCROLL_UP) );
        }
        else if ( direction == SCROLL_DOWN ) {
            scrollDirection = SCROLL_DOWN;
            Dimension size = scroller.getSize();
            Point convertedPoint = SwingUtilities.convertPoint( scroller,
                                                                new Point( 1, (size.height - 1) - 2 ),
                                                                list );
            int bottom = list.locationToIndex( convertedPoint );
            list.setSelectedIndex( bottom );

            autoscrollTimer = new Timer(100, new AutoScrollActionHandler(
                                            SCROLL_DOWN));
        }
        autoscrollTimer.start();
    }

    /**
     * This protected method is implementation specific and should be private.
     * do not call or override.
     */
    protected void stopAutoScrolling() {
        isAutoScrolling = false;

        if ( autoscrollTimer != null ) {
            autoscrollTimer.stop();
            autoscrollTimer = null;
        }
    }

    /**
     * This protected method is implementation specific and should be private.
     * do not call or override.
     */
    protected void autoScrollUp() {
        int index = list.getSelectedIndex();
        if ( index > 0 ) {
            list.setSelectedIndex( index - 1 );
            list.ensureIndexIsVisible( index - 1 );
        }
    }

    /**
     * This protected method is implementation specific and should be private.
     * do not call or override.
     */
    protected void autoScrollDown() {
        int index = list.getSelectedIndex();
        int lastItem = list.getModel().getSize() - 1;
        if ( index < lastItem ) {
            list.setSelectedIndex( index + 1 );
            list.ensureIndexIsVisible( index + 1 );
        }
    }

    //
    // end Autoscroll methods
    //=================================================================


    //===================================================================
    // begin Utility methods
    //

    /**
     * Gets the AccessibleContext associated with this BasicComboPopup.
     * The AccessibleContext will have its parent set to the ComboBox.
     *
     * @return an AccessibleContext for the BasicComboPopup
     * @since 1.5
     */
    public AccessibleContext getAccessibleContext() {
        AccessibleContext context = super.getAccessibleContext();
        context.setAccessibleParent(comboBox);
        return context;
    }


    /**
     * This is is a utility method that helps event handlers figure out where to
     * send the focus when the popup is brought up.  The standard implementation
     * delegates the focus to the editor (if the combo box is editable) or to
     * the JComboBox if it is not editable.
     */
    protected void delegateFocus( MouseEvent e ) {
        if ( comboBox.isEditable() ) {
            Component comp = comboBox.getEditor().getEditorComponent();
            if ((!(comp instanceof JComponent)) || ((JComponent)comp).isRequestFocusEnabled()) {
                comp.requestFocus();
            }
        }
        else if (comboBox.isRequestFocusEnabled()) {
            comboBox.requestFocus();
        }
    }

    /**
     * Makes the popup visible if it is hidden and makes it hidden if it is 
     * visible.
     */
    protected void togglePopup() {
        if ( isVisible() ) {
            hide();
        }
        else {
            show();
        }
    }

    /**
     * Sets the list selection index to the selectedIndex. This 
     * method is used to synchronize the list selection with the 
     * combo box selection.
     * 
     * @param selectedIndex the index to set the list
     */
    private void setListSelection(int selectedIndex) {
        if ( selectedIndex == -1 ) {
            list.clearSelection();
        }
        else {
            list.setSelectedIndex( selectedIndex );
	    list.ensureIndexIsVisible( selectedIndex );
        }
    }

    protected MouseEvent convertMouseEvent( MouseEvent e ) {
        Point convertedPoint = SwingUtilities.convertPoint( (Component)e.getSource(),
                                                            e.getPoint(), list );
        MouseEvent newEvent = new MouseEvent( (Component)e.getSource(),
                                              e.getID(),
                                              e.getWhen(),
                                              e.getModifiers(),
                                              convertedPoint.x,
                                              convertedPoint.y,
                                              e.getXOnScreen(),
                                              e.getYOnScreen(),
                                              e.getClickCount(),
                                              e.isPopupTrigger(),
                                              MouseEvent.NOBUTTON );
        return newEvent;
    }


    /**
     * Retrieves the height of the popup based on the current
     * ListCellRenderer and the maximum row count.
     */
    protected int getPopupHeightForRowCount(int maxRowCount) {
	// Set the cached value of the minimum row count
        int minRowCount = Math.min( maxRowCount, comboBox.getItemCount() );
        int height = 0;
        ListCellRenderer renderer = list.getCellRenderer();
        Object value = null;

        for ( int i = 0; i < minRowCount; ++i ) {
            value = list.getModel().getElementAt( i );
            Component c = renderer.getListCellRendererComponent( list, value, i, false, false );
            height += c.getPreferredSize().height;
        }
        
        if (height == 0) {
            height = comboBox.getHeight();
        }
        
        Border border = scroller.getViewportBorder();
        if (border != null) {
            Insets insets = border.getBorderInsets(null);
            height += insets.top + insets.bottom;
        }
        
        border = scroller.getBorder();
        if (border != null) {
            Insets insets = border.getBorderInsets(null);
            height += insets.top + insets.bottom;
        }
        
        return height;
    }

    /**
     * Calculate the placement and size of the popup portion of the combo box based
     * on the combo box location and the enclosing screen bounds. If
     * no transformations are required, then the returned rectangle will
     * have the same values as the parameters.
     * 
     * @param px starting x location
     * @param py starting y location
     * @param pw starting width
     * @param ph starting height
     * @return a rectangle which represents the placement and size of the popup
     */
    protected Rectangle computePopupBounds(int px,int py,int pw,int ph) {
	Toolkit toolkit = Toolkit.getDefaultToolkit();
        Rectangle screenBounds;

	// Calculate the desktop dimensions relative to the combo box.
        GraphicsConfiguration gc = comboBox.getGraphicsConfiguration();
        Point p = new Point();
        SwingUtilities.convertPointFromScreen(p, comboBox);
        if (gc != null) {
	    Insets screenInsets = toolkit.getScreenInsets(gc);
            screenBounds = gc.getBounds();
	    screenBounds.width -= (screenInsets.left + screenInsets.right);
	    screenBounds.height -= (screenInsets.top + screenInsets.bottom);
            screenBounds.x += (p.x + screenInsets.left);
            screenBounds.y += (p.y + screenInsets.top);
        }
        else {
            screenBounds = new Rectangle(p, toolkit.getScreenSize());
        }

        Rectangle rect = new Rectangle(px,py,pw,ph);
        if (py+ph > screenBounds.y+screenBounds.height
	    && ph < screenBounds.height) {
	    rect.y = -rect.height;
	}
	return rect;
    }

    /**
     * Calculates the upper left location of the Popup.
     */
    private Point getPopupLocation() {
	Dimension popupSize = comboBox.getSize();
	Insets insets = getInsets();

	// reduce the width of the scrollpane by the insets so that the popup
	// is the same width as the combo box.
	popupSize.setSize(popupSize.width - (insets.right + insets.left), 
			  getPopupHeightForRowCount( comboBox.getMaximumRowCount()));
	Rectangle popupBounds = computePopupBounds( 0, comboBox.getBounds().height,
                                                    popupSize.width, popupSize.height);
	Dimension scrollSize = popupBounds.getSize();
	Point popupLocation = popupBounds.getLocation();
	    
	scroller.setMaximumSize( scrollSize );
	scroller.setPreferredSize( scrollSize );
	scroller.setMinimumSize( scrollSize );
	
	list.revalidate();

	return popupLocation;
    }

    /**
     * A utility method used by the event listeners.  Given a mouse event, it changes
     * the list selection to the list item below the mouse.
     */
    protected void updateListBoxSelectionForEvent(MouseEvent anEvent,boolean shouldScroll) {
	// XXX - only seems to be called from this class. shouldScroll flag is
	// never true
        Point location = anEvent.getPoint();
        if ( list == null )
            return;
        int index = list.locationToIndex(location);
        if ( index == -1 ) {
            if ( location.y < 0 )
                index = 0;
            else
                index = comboBox.getModel().getSize() - 1;
        }
        if ( list.getSelectedIndex() != index ) {
            list.setSelectedIndex(index);
            if ( shouldScroll )
                list.ensureIndexIsVisible(index);
        }
    }

    //
    // end Utility methods
    //=================================================================
}