basiccomboboxui.java

java1.6众多例子参考

            if ( isTableCellEditor ) {
                listBox.setSelectedIndex( si - 1 );
                listBox.ensureIndexIsVisible( si - 1 );
            }
            else {
                comboBox.setSelectedIndex(si-1);
            }

            comboBox.repaint();
        }
    }

    /**
     * Hides the popup if it is showing and shows the popup if it is hidden.
     */
    protected void toggleOpenClose() {
        setPopupVisible(comboBox, !isPopupVisible(comboBox));
    }

    /**
     * Returns the area that is reserved for drawing the currently selected item.
     */
    protected Rectangle rectangleForCurrentValue() {
        int width = comboBox.getWidth();
        int height = comboBox.getHeight();
        Insets insets = getInsets();
        int buttonSize = height - (insets.top + insets.bottom);
	if ( arrowButton != null ) {
            buttonSize = arrowButton.getWidth();
	}
	if(BasicGraphicsUtils.isLeftToRight(comboBox)) {
	    return new Rectangle(insets.left, insets.top,
			     width - (insets.left + insets.right + buttonSize),
                             height - (insets.top + insets.bottom));
	}
	else {
	    return new Rectangle(insets.left + buttonSize, insets.top,
			     width - (insets.left + insets.right + buttonSize),
                             height - (insets.top + insets.bottom));
	}
    }

    /**
     * Gets the insets from the JComboBox.
     */
    protected Insets getInsets() {
        return comboBox.getInsets();
    }

    //
    // end Utility Methods
    //====================


    //===============================
    // begin Painting Utility Methods
    //

    /**
     * Paints the currently selected item.
     */
    public void paintCurrentValue(Graphics g,Rectangle bounds,boolean hasFocus) {
        ListCellRenderer renderer = comboBox.getRenderer();
        Component c;

        if ( hasFocus && !isPopupVisible(comboBox) ) {
            c = renderer.getListCellRendererComponent( listBox,
                                                       comboBox.getSelectedItem(),
                                                       -1,
                                                       true,
                                                       false );
        }
        else {
            c = renderer.getListCellRendererComponent( listBox,
                                                       comboBox.getSelectedItem(),
                                                       -1,
                                                       false,
                                                       false );
            c.setBackground(UIManager.getColor("ComboBox.background"));
        }
        c.setFont(comboBox.getFont());
        if ( hasFocus && !isPopupVisible(comboBox) ) {
            c.setForeground(listBox.getSelectionForeground());
            c.setBackground(listBox.getSelectionBackground());
        }
        else {
            if ( comboBox.isEnabled() ) {
                c.setForeground(comboBox.getForeground());
                c.setBackground(comboBox.getBackground());
            }
            else {
                c.setForeground(DefaultLookup.getColor(
                         comboBox, this, "ComboBox.disabledForeground", null));
                c.setBackground(DefaultLookup.getColor(
                         comboBox, this, "ComboBox.disabledBackground", null));
            }
        }

        // Fix for 4238829: should lay out the JPanel.
        boolean shouldValidate = false;
        if (c instanceof JPanel)  {
            shouldValidate = true;
        }

        int x = bounds.x, y = bounds.y, w = bounds.width, h = bounds.height;
        if (padding != null) {
            x = bounds.x + padding.left;
            y = bounds.y + padding.top;
            w = bounds.width - (padding.left + padding.right);
            h = bounds.height - (padding.top + padding.bottom);
        }
        
        currentValuePane.paintComponent(g,c,comboBox,x,y,w,h,shouldValidate);
    }

    /**
     * Paints the background of the currently selected item.
     */
    public void paintCurrentValueBackground(Graphics g,Rectangle bounds,boolean hasFocus) {
        Color t = g.getColor();
        if ( comboBox.isEnabled() )
            g.setColor(DefaultLookup.getColor(comboBox, this,
                                              "ComboBox.background", null));
        else
            g.setColor(DefaultLookup.getColor(comboBox, this,
                                     "ComboBox.disabledBackground", null));
        g.fillRect(bounds.x,bounds.y,bounds.width,bounds.height);
        g.setColor(t);
    }

    /**
     * Repaint the currently selected item.
     */
    void repaintCurrentValue() {
        Rectangle r = rectangleForCurrentValue();
        comboBox.repaint(r.x,r.y,r.width,r.height);
    }

    //
    // end Painting Utility Methods
    //=============================


    //===============================
    // begin Size Utility Methods
    //

    /** 
     * Return the default size of an empty display area of the combo box using
     * the current renderer and font.
     *
     * @return the size of an empty display area
     * @see #getDisplaySize
     */
    protected Dimension getDefaultSize() {
	// Calculates the height and width using the default text renderer
	Dimension d = getSizeForComponent(getDefaultListCellRenderer().getListCellRendererComponent(listBox, " ", -1, false, false));

        return new Dimension(d.width, d.height);
    }

    /** 
     * Returns the calculated size of the display area. The display area is the
     * portion of the combo box in which the selected item is displayed. This 
     * method will use the prototype display value if it has been set. 
     * <p>
     * For combo boxes with a non trivial number of items, it is recommended to
     * use a prototype display value to significantly speed up the display 
     * size calculation.
     * 
     * @return the size of the display area calculated from the combo box items
     * @see javax.swing.JComboBox#setPrototypeDisplayValue
     */
    protected Dimension getDisplaySize() {
        if (!isDisplaySizeDirty)  {
            return new Dimension(cachedDisplaySize);
        }
	Dimension result = new Dimension();
        
        ListCellRenderer renderer = comboBox.getRenderer();
        if (renderer == null)  {
            renderer = new DefaultListCellRenderer();
        }

        sameBaseline = true;

        Object prototypeValue = comboBox.getPrototypeDisplayValue();
        if (prototypeValue != null)  {
            // Calculates the dimension based on the prototype value
            result = getSizeForComponent(renderer.getListCellRendererComponent(listBox, 
									       prototypeValue,
									       -1, false, false));
        } else {
            // Calculate the dimension by iterating over all the elements in the combo
            // box list.
            ComboBoxModel model = comboBox.getModel();
            int modelSize = model.getSize();
            int baseline = -1;
	    Dimension d;

            Component cpn;
            
            if (modelSize > 0 ) {
                for (int i = 0; i < modelSize ; i++ ) {
                    // Calculates the maximum height and width based on the largest
                    // element
                    Object value = model.getElementAt(i);
                    Component c = renderer.getListCellRendererComponent(
                            listBox, value, -1, false, false);
                    d = getSizeForComponent(c);
                    if (sameBaseline && value != null &&
                            (!(value instanceof String) || !"".equals(value))) {
                        int newBaseline = c.getBaseline(d.width, d.height);
                        if (newBaseline == -1) {
                            sameBaseline = false;
                        }
                        else if (baseline == -1) {
                            baseline = newBaseline;
                        }
                        else if (baseline != newBaseline) {
                            sameBaseline = false;
                        }
                    }
                    result.width = Math.max(result.width,d.width);
                    result.height = Math.max(result.height,d.height);
                }
            } else {
		result = getDefaultSize();
		if (comboBox.isEditable()) {
		    result.width = 100;
		}
            }
        }

	if ( comboBox.isEditable() ) {
	    Dimension d = editor.getPreferredSize();
	    result.width = Math.max(result.width,d.width);
	    result.height = Math.max(result.height,d.height);
	}
        
        // calculate in the padding
        if (padding != null) {
            result.width += padding.left + padding.right;
            result.height += padding.top + padding.bottom;
        }
        
        // Set the cached value
        cachedDisplaySize.setSize(result.width, result.height);
        isDisplaySizeDirty = false;

        return result;
    }

    /**
     * This has been refactored out in hopes that it may be investigated and
     * simplified for the next major release. adding/removing
     * the component to the currentValuePane and changing the font may be 
     * redundant operations.
     */
    private Dimension getSizeForComponent(Component comp) {
	currentValuePane.add(comp);
	comp.setFont(comboBox.getFont());
	Dimension d = comp.getPreferredSize();
	currentValuePane.remove(comp);
	return d;
    }
	

    //
    // end Size Utility Methods
    //=============================


    //=================================
    // begin Keyboard Action Management
    //

    /**
     * Adds keyboard actions to the JComboBox.  Actions on enter and esc are already
     * supplied.  Add more actions as you need them.
     */
    protected void installKeyboardActions() {
	InputMap km = getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
	SwingUtilities.replaceUIInputMap(comboBox, JComponent.
			     WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, km);


        LazyActionMap.installLazyActionMap(comboBox, BasicComboBoxUI.class,
                                           "ComboBox.actionMap");
    }

    InputMap getInputMap(int condition) {
	if (condition == JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT) {
	    return (InputMap)DefaultLookup.get(comboBox, this,
                                               "ComboBox.ancestorInputMap");
	}
	return null;
    }

    boolean isTableCellEditor() {
	return isTableCellEditor;
    }

    /**
     * Removes the focus InputMap and ActionMap.
     */
    protected void uninstallKeyboardActions() {
	SwingUtilities.replaceUIInputMap(comboBox, JComponent.
				 WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, null);
	SwingUtilities.replaceUIActionMap(comboBox, null);
    }


    //
    // Actions
    // 
    private static class Actions extends UIAction {
        private static final String HIDE = "hidePopup";
        private static final String DOWN = "selectNext";
        private static final String DOWN_2 = "selectNext2";
        private static final String TOGGLE = "togglePopup";
        private static final String TOGGLE_2 = "spacePopup";
        private static final String UP = "selectPrevious";
        private static final String UP_2 = "selectPrevious2";
        private static final String ENTER = "enterPressed";
        private static final String PAGE_DOWN = "pageDownPassThrough";
        private static final String PAGE_UP = "pageUpPassThrough";
        private static final String HOME = "homePassThrough";
        private static final String END = "endPassThrough";

        Actions(String name) {
            super(name);
        }

	public void actionPerformed( ActionEvent e ) {
            String key = getName();
            JComboBox comboBox = (JComboBox)e.getSource();
            BasicComboBoxUI ui = (BasicComboBoxUI)BasicLookAndFeel.getUIOfType(
                                  comboBox.getUI(), BasicComboBoxUI.class);
            if (key == HIDE) {
                comboBox.firePopupMenuCanceled();
                comboBox.setPopupVisible(false);
            }
            else if (key == PAGE_DOWN || key == PAGE_UP ||
                     key == HOME || key == END) {
                int index = getNextIndex(comboBox, key);
                if (index >= 0 && index < comboBox.getItemCount()) {
                    comboBox.setSelectedIndex(index);
                }
            }
            else if (key == DOWN) {
                if (comboBox.isShowing() ) {
                    if ( comboBox.isPopupVisible() ) {
                        if (ui != null) {
                            ui.selectNextPossibleValue();
                        }
                    } else {
                        comboBox.setPopupVisible(true);
                    }
                }
            }
            else if (key == DOWN_2) {
		// Special case in which pressing the arrow keys will not 
		// make the popup appear - except for editable combo boxes
                // and combo boxes inside a table.
                if (comboBox.isShowing() ) {
                    if ( (comboBox.isEditable() ||
                            (ui != null && ui.isTableCellEditor()))
                         && !comboBox.isPopupVisible() ) {
                        comboBox.setPopupVisible(true);
                    } else {
                        if (ui != null) {
                            ui.selectNextPossibleValue();
                        }
                    }
                }