basicpopupmenuui.java

java jdk 1.4的源码

                    path[len-1] = nextChild;
                    msm.setSelectedPath(path);
		}
	    }
	}
    }

    private static class SelectParentChildAction extends AbstractAction {
        static boolean PARENT = false;
        static boolean CHILD = true;
        boolean direction;

        SelectParentChildAction(boolean dir) {
            direction = dir;
        }

	public void actionPerformed(ActionEvent e) {
            MenuSelectionManager msm = MenuSelectionManager.defaultManager();
            MenuElement path[] = msm.getSelectedPath();
            int len = path.length;

            if (direction == PARENT) {
                // selecting parent
                int popupIndex = len-1;

                if (len > 2 &&
                    // check if we have an open submenu. A submenu item may or
                    // may not be selected, so submenu popup can be either the
                    // last or next to the last item.
                    (path[popupIndex] instanceof JPopupMenu ||
                     path[--popupIndex] instanceof JPopupMenu) &&
                    !((JMenu)path[popupIndex-1]).isTopLevelMenu()) {

                    // we have a submenu, just close it
                    MenuElement newPath[] = new MenuElement[popupIndex];
                    System.arraycopy(path, 0, newPath, 0, popupIndex);
                    msm.setSelectedPath(newPath);
                    return;
                }
            } else {
                // selecting child
                if (len > 0 && path[len-1] instanceof JMenu &&
                    !((JMenu)path[len-1]).isTopLevelMenu()) {

                    // we have a submenu, open it
                    JMenu menu = (JMenu)path[len-1];
                    JPopupMenu popup = menu.getPopupMenu();
                    MenuElement[] subs = popup.getSubElements();
                    MenuElement item = findEnabledChild(subs, -1, true);
                    MenuElement[] newPath;

                    if (item == null) {
                        newPath = new MenuElement[len+1];
                    } else {
                        newPath = new MenuElement[len+2];
                        newPath[len+1] = item;
                    }
                    System.arraycopy(path, 0, newPath, 0, len);
                    newPath[len] = popup;
                    msm.setSelectedPath(newPath);
                    return;
                }
            }

            // check if we have a toplevel menu selected.
            // If this is the case, we select another toplevel menu
	    if (len > 1 && path[0] instanceof JMenuBar) {
                MenuElement currentMenu = path[1];
		MenuElement nextMenu = findEnabledChild(
                    path[0].getSubElements(), currentMenu, direction);

		if (nextMenu != null && nextMenu != currentMenu) {
		    MenuElement newSelection[];
		    if (len == 2) {
                        // menu is selected but its popup not shown
			newSelection = new MenuElement[2];
			newSelection[0] = path[0];
			newSelection[1] = nextMenu;
		    } else {
                        // menu is selected and its popup is shown
			newSelection = new MenuElement[3];
			newSelection[0] = path[0];
			newSelection[1] = nextMenu;
			newSelection[2] = ((JMenu)nextMenu).getPopupMenu();
                    }
		    msm.setSelectedPath(newSelection);
		}
	    }
	}
    }

    /**
     * This helper is added to MenuSelectionManager as a ChangeListener to 
     * listen to menu selection changes. When a menu is activated, it passes
     * focus to its parent JRootPane, and installs an ActionMap/InputMap pair
     * on that JRootPane. Those maps are necessary in order for menu
     * navigation to work. When menu is being deactivated, it restores focus
     * to the component that has had it before menu activation, and uninstalls
     * the maps.
     * This helper is also installed as a KeyListener on root pane when menu
     * is active. It forwards key events to MenuSelectionManager for mnemonic
     * keys handling.
     */
    private static class MenuKeyboardHelper
        implements ChangeListener, KeyListener {

        private Component lastFocused = null;
  	private MenuElement[] lastPathSelected = new MenuElement[0];
        private JPopupMenu lastPopup;

        private JRootPane invokerRootPane;
        private ActionMap menuActionMap = getActionMap();
        private InputMap menuInputMap;
        private boolean focusTraversalKeysEnabled;

        /*
         * Fix for 4213634
         * If this is false, KEY_TYPED and KEY_RELEASED events are NOT
         * processed. This is needed to avoid activating a menuitem when
         * the menu and menuitem share the same mnemonic.
         */
        private boolean receivedKeyPressed = false;

        void removeItems() {
            if (lastFocused != null) {
                if(!lastFocused.requestFocusInWindow()) {
                    // Workarounr for 4810575.
                    // If lastFocused is not in currently focused window
                    // requestFocusInWindow will fail. In this case we must
                    // request focus by requestFocus() if it was not
                    // transferred from our popup.
                    Window cfw = KeyboardFocusManager
                                 .getCurrentKeyboardFocusManager()
                                  .getFocusedWindow();
                    if(cfw != null &&
                       "###focusableSwingPopup###".equals(cfw.getName())) {
                        lastFocused.requestFocus();
                    }

                }
                lastFocused = null;
            }
            if (invokerRootPane != null) {
                invokerRootPane.removeKeyListener(menuKeyboardHelper);
                invokerRootPane.setFocusTraversalKeysEnabled(focusTraversalKeysEnabled);
                removeUIInputMap(invokerRootPane, menuInputMap);
                removeUIActionMap(invokerRootPane, menuActionMap);
                invokerRootPane = null;
            } 
            receivedKeyPressed = false;
        }

        private FocusListener rootPaneFocusListener = new FocusAdapter() {
                public void focusGained(FocusEvent ev) {
                    Component opposite = ev.getOppositeComponent();
                    if (opposite != null) {
                        lastFocused = opposite;
                    }
                    ev.getComponent().removeFocusListener(this);
                }
            };

        /**
         * Return the last JPopupMenu in <code>path</code>,
         * or <code>null</code> if none found
         */
        JPopupMenu getActivePopup(MenuElement[] path) {
            for (int i=path.length-1; i>=0; i--) {
                MenuElement elem = path[i];
                if (elem instanceof JPopupMenu) {
                    return (JPopupMenu)elem;
                }
            }
            return null;
        }

        void addUIInputMap(JComponent c, InputMap map) {
            InputMap lastNonUI = null;
            InputMap parent = c.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);

            while (parent != null && !(parent instanceof UIResource)) {
                lastNonUI = parent;
                parent = parent.getParent();
            }

            if (lastNonUI == null) {
                c.setInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW, map);
            } else {
                lastNonUI.setParent(map);
            }
            map.setParent(parent);
        }

        void addUIActionMap(JComponent c, ActionMap map) {
            ActionMap lastNonUI = null;
            ActionMap parent = c.getActionMap();

            while (parent != null && !(parent instanceof UIResource)) {
                lastNonUI = parent;
                parent = parent.getParent();
            }

            if (lastNonUI == null) {
                c.setActionMap(map);
            } else {
                lastNonUI.setParent(map);
            }
            map.setParent(parent);
        }

        void removeUIInputMap(JComponent c, InputMap map) {
            InputMap im = null;
            InputMap parent = c.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);

            while (parent != null) {
                if (parent == map) {
                    if (im == null) {
                        c.setInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW,
                                      map.getParent());
                    } else {
                        im.setParent(map.getParent());
                    }
                    break;
                }
                im = parent;
                parent = parent.getParent();
            }
        }

        void removeUIActionMap(JComponent c, ActionMap map) {
            ActionMap im = null;
            ActionMap parent = c.getActionMap();

            while (parent != null) {
                if (parent == map) {
                    if (im == null) {
                        c.setActionMap(map.getParent());
                    } else {
                        im.setParent(map.getParent());
                    }
                    break;
                }
                im = parent;
                parent = parent.getParent();
            }
        }

        public void stateChanged(ChangeEvent ev) {
            if (!(UIManager.getLookAndFeel() instanceof BasicLookAndFeel)) {
                MenuSelectionManager msm = MenuSelectionManager.
                                           defaultManager();
                msm.removeChangeListener(this);
                menuKeyboardHelperInstalled = false;
                return;
            }
	    MenuSelectionManager msm = (MenuSelectionManager)ev.getSource();
	    MenuElement[] p = msm.getSelectedPath();
            JPopupMenu popup = getActivePopup(p);
            if (popup != null && !popup.isFocusable()) {
                // Do nothing for non-focusable popups
                return;
            }

            if   (lastPathSelected.length != 0 && p.length != 0 ) {
                if (!checkInvokerEqual(p[0],lastPathSelected[0])) {
                        removeItems();
                        lastPathSelected = new MenuElement[0];
                        }

        	}




	    if (lastPathSelected.length == 0 && p.length > 0) {
                // menu posted
                JComponent invoker;

                if (popup == null) {
                    if (p.length == 2 && p[0] instanceof JMenuBar &&
                        p[1] instanceof JMenu) {
                        // a menu has been selected but not open
                        invoker = (JComponent)p[1];
                        popup = ((JMenu)invoker).getPopupMenu();
                    } else {
                        return;
                    }
                } else {
                    Component c = popup.getInvoker();
                    if(c instanceof JFrame) {
                        invoker = ((JFrame)c).getRootPane();
                    } else if(c instanceof JApplet) {
                        invoker = ((JApplet)c).getRootPane();
                    } else {
                        while (!(c instanceof JComponent)) {
                            if (c == null) {
                                return;
                            }
                            c = c.getParent();
                        }
                        invoker = (JComponent)c;
                    }
                }

                // remember current focus owner
                lastFocused = KeyboardFocusManager.
                    getCurrentKeyboardFocusManager().getFocusOwner();

                // request focus on root pane and install keybindings
                // used for menu navigation
                invokerRootPane = SwingUtilities.getRootPane(invoker);
                if (invokerRootPane != null) {
                    invokerRootPane.addFocusListener(rootPaneFocusListener);
                    invokerRootPane.requestFocus(true);
                    invokerRootPane.addKeyListener(menuKeyboardHelper);
                    focusTraversalKeysEnabled = invokerRootPane.
                                      getFocusTraversalKeysEnabled();
                    invokerRootPane.setFocusTraversalKeysEnabled(false);

                    menuInputMap = getInputMap(popup, invokerRootPane);
                    addUIInputMap(invokerRootPane, menuInputMap);
                    addUIActionMap(invokerRootPane, menuActionMap);
                }
            } else if (lastPathSelected.length != 0 && p.length == 0) {
		// menu hidden -- return focus to where it had been before
                // and uninstall menu keybindings
                   removeItems();
	    } else {
                if (popup != lastPopup) {
                    receivedKeyPressed = false;
                }
            }

            // Remember the last path selected
            lastPathSelected = p;
            lastPopup = popup;
        }

        public void keyPressed(KeyEvent ev) {
            receivedKeyPressed = true;
            MenuSelectionManager.defaultManager().processKeyEvent(ev);
        }

        public void keyReleased(KeyEvent ev) {
	    if (receivedKeyPressed) {
		receivedKeyPressed = false;
                MenuSelectionManager.defaultManager().processKeyEvent(ev);
            }
        }

        public void keyTyped(KeyEvent ev) {
	    if (receivedKeyPressed) {
                MenuSelectionManager.defaultManager().processKeyEvent(ev);
            }
        }
    }
}