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      1 /*
      2  * Copyright (C) 2011 The Android Open Source Project
      3  *
      4  * Licensed under the Eclipse Public License, Version 1.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.eclipse.org/org/documents/epl-v10.php
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.menubar;
     18 
     19 import org.eclipse.jface.action.IAction;
     20 import org.eclipse.jface.action.IMenuManager;
     21 import org.eclipse.jface.action.Separator;
     22 import org.eclipse.swt.SWT;
     23 import org.eclipse.swt.events.SelectionAdapter;
     24 import org.eclipse.swt.events.SelectionEvent;
     25 import org.eclipse.swt.widgets.Display;
     26 import org.eclipse.swt.widgets.Menu;
     27 import org.eclipse.swt.widgets.MenuItem;
     28 
     29 
     30 /**
     31  * On Mac, {@link MenuBarEnhancer#setupMenu} plugs a listener on the About and the
     32  * Preferences menu items of the standard "application" menu in the menu bar.
     33  * On Windows or Linux, it adds relevant items to a given {@link Menu} linked to
     34  * the same listeners.
     35  */
     36 public final class MenuBarEnhancer {
     37 
     38     private MenuBarEnhancer() {
     39     }
     40 
     41     /**
     42      * Creates an instance of {@link IMenuBarEnhancer} specific to the current platform
     43      * and invoke its {@link IMenuBarEnhancer#setupMenu} to updates the menu bar.
     44      * <p/>
     45      * Depending on the platform, this will either hook into the existing About menu item
     46      * and a Preferences or Options menu item or add new ones to the given {@code swtMenu}.
     47      * Depending on the platform, the menu items might be decorated with the
     48      * given {@code appName}.
     49      * <p/>
     50      * Potential errors are reported through {@link IMenuBarCallback}.
     51      *
     52      * @param appName Name used for the About menu item and similar. Must not be null.
     53      * @param swtMenu For non-mac platform this is the menu where the "About" and
     54      *          the "Options" menu items are created. Typically the menu might be
     55      *          called "Tools". Must not be null.
     56      * @param callbacks Callbacks called when "About" and "Preferences" menu items are invoked.
     57      *          Must not be null.
     58      * @return A actual {@link IMenuBarEnhancer} implementation. Never null.
     59      *          This is currently not of any use for the caller but is left in case
     60      *          we want to expand the functionality later.
     61      */
     62     public static IMenuBarEnhancer setupMenu(
     63             String appName,
     64             final Menu swtMenu,
     65             IMenuBarCallback callbacks) {
     66 
     67         IMenuBarEnhancer enhancer = getEnhancer(callbacks);
     68 
     69         // Default implementation for generic platforms
     70         if (enhancer == null) {
     71             enhancer = new IMenuBarEnhancer() {
     72 
     73                 public MenuBarMode getMenuBarMode() {
     74                     return MenuBarMode.GENERIC;
     75                 }
     76 
     77                 public void setupMenu(
     78                         String appName,
     79                         Display display,
     80                         final IMenuBarCallback callbacks) {
     81                     if (swtMenu.getItemCount() > 0) {
     82                         new MenuItem(swtMenu, SWT.SEPARATOR);
     83                     }
     84 
     85                     // Note: we use "Preferences" on Mac and "Options" on Windows/Linux.
     86                     final MenuItem pref = new MenuItem(swtMenu, SWT.NONE);
     87                     pref.setText("&Options...");
     88 
     89                     final MenuItem about = new MenuItem(swtMenu, SWT.NONE);
     90                     about.setText("&About...");
     91 
     92                     pref.addSelectionListener(new SelectionAdapter() {
     93                         @Override
     94                         public void widgetSelected(SelectionEvent e) {
     95                             try {
     96                                 pref.setEnabled(false);
     97                                 callbacks.onPreferencesMenuSelected();
     98                                 super.widgetSelected(e);
     99                             } finally {
    100                                 pref.setEnabled(true);
    101                             }
    102                         }
    103                     });
    104 
    105                     about.addSelectionListener(new SelectionAdapter() {
    106                         @Override
    107                         public void widgetSelected(SelectionEvent e) {
    108                             try {
    109                                 about.setEnabled(false);
    110                                 callbacks.onAboutMenuSelected();
    111                                 super.widgetSelected(e);
    112                             } finally {
    113                                 about.setEnabled(true);
    114                             }
    115                         }
    116                     });
    117                 }
    118             };
    119         }
    120 
    121         enhancer.setupMenu(appName, swtMenu.getDisplay(), callbacks);
    122         return enhancer;
    123     }
    124 
    125 
    126     public static IMenuBarEnhancer setupMenuManager(
    127             String appName,
    128             Display display,
    129             final IMenuManager menuManager,
    130             final IAction aboutAction,
    131             final IAction preferencesAction,
    132             final IAction quitAction) {
    133 
    134         IMenuBarCallback callbacks = new IMenuBarCallback() {
    135             public void printError(String format, Object... args) {
    136                 System.err.println(String.format(format, args));
    137             }
    138 
    139             public void onPreferencesMenuSelected() {
    140                 if (preferencesAction != null) {
    141                     preferencesAction.run();
    142                 }
    143             }
    144 
    145             public void onAboutMenuSelected() {
    146                 if (aboutAction != null) {
    147                     aboutAction.run();
    148                 }
    149             }
    150         };
    151 
    152         IMenuBarEnhancer enhancer = getEnhancer(callbacks);
    153 
    154         // Default implementation for generic platforms
    155         if (enhancer == null) {
    156             enhancer = new IMenuBarEnhancer() {
    157 
    158                 public MenuBarMode getMenuBarMode() {
    159                     return MenuBarMode.GENERIC;
    160                 }
    161 
    162                 public void setupMenu(
    163                         String appName,
    164                         Display display,
    165                         final IMenuBarCallback callbacks) {
    166                     if (!menuManager.isEmpty()) {
    167                         menuManager.add(new Separator());
    168                     }
    169 
    170                     if (aboutAction != null) {
    171                         menuManager.add(aboutAction);
    172                     }
    173                     if (preferencesAction != null) {
    174                         menuManager.add(preferencesAction);
    175                     }
    176                     if (quitAction != null) {
    177                         if (aboutAction != null || preferencesAction != null) {
    178                             menuManager.add(new Separator());
    179                         }
    180                         menuManager.add(quitAction);
    181                     }
    182                 }
    183             };
    184         }
    185 
    186         enhancer.setupMenu(appName, display, callbacks);
    187         return enhancer;
    188     }
    189 
    190     private static IMenuBarEnhancer getEnhancer(IMenuBarCallback callbacks) {
    191         IMenuBarEnhancer enhancer = null;
    192         String p = SWT.getPlatform();
    193         String className = null;
    194         if ("cocoa".equals(p)) {                                                  //$NON-NLS-1$
    195             className = "com.android.menubar.internal.MenuBarEnhancerCocoa";      //$NON-NLS-1$
    196         }
    197 
    198         if (System.getenv("DEBUG_SWTMENUBAR") != null) {
    199             callbacks.printError("DEBUG SwtMenuBar: SWT=%1$s, class=%2$s", p, className);
    200         }
    201 
    202         if (className != null) {
    203             try {
    204                 Class<?> clazz = Class.forName(className);
    205                 enhancer = (IMenuBarEnhancer) clazz.newInstance();
    206             } catch (Exception e) {
    207                 // Log an error and fallback on the default implementation.
    208                 callbacks.printError(
    209                         "Failed to instantiate %1$s: %2$s",                       //$NON-NLS-1$
    210                         className,
    211                         e.toString());
    212             }
    213         }
    214         return enhancer;
    215     }
    216 }
    217