demomenu.java

这是我在测试手机java时候做的java菜单程序

/*==============================================================================

FILE:  DemoMenu.java

GENERAL DESCRIPTION:
   MIDlet to display menu of demonstration MIDlets.

Copyright (c) 2002 Qualcomm Inc.  All rights reserved.
==============================================================================*/

package com.qualcomm.demo.menu;

import javax.microedition.midlet.MIDlet;
import javax.microedition.lcdui.*;
import java.lang.*;
import com.sun.midp.midlet.Scheduler;
import com.qualcomm.midp.Main;
import javax.microedition.io.Connector;
import com.sun.midp.io.j2me.storage.RandomAccessStream;
import com.qualcomm.qjaeservices.file.FileService;
import java.util.*;

/**
 * DemoMenu MIDlet.
 */
public class DemoMenu extends MIDlet implements CommandListener
{
   // Copyright text to display when "About" softkey pressed
   private final String aboutText =
      "Copyright 2002 Qualcomm Inc.\n" +
      "All Rights Reserved.\n\n" +
      "Memory Size: " + Runtime.getRuntime().totalMemory();

   // MIDlet to instantiate when Intro is chosen
   private final String INTRO_MIDLET = "com.qualcomm.demo.menu.DemoIntro";

   // MIDlet to instantiate when TCKMode is chosen
   private final String TCK_MODE_MIDLET = "com.qualcomm.demo.misc.TCKMode";

   // MIDlet to instantiate when External Midlets is chosen
   private final String MIDLET_BROWSER = "com.qualcomm.demo.menu.MidletBrowser";

   // Display for this MIDlet
   private Display display;

   // Fixed softkeys for "main menu" screen
   private final Command externalCommand =
      new Command("External MIDlets", Command.SCREEN, 101);
   private final Command managerCommand =
      new Command("AMS Manager", Command.SCREEN, 102);
   private final Command introCommand =
      new Command("Java Introduction", Command.SCREEN, 103);
   private final Command tckModeCommand =
      new Command("TCK Mode", Command.SCREEN, 104);
   private final Command debugCommand =
      new Command("Debug", Command.SCREEN, 105);
   private final Command aboutCommand =
      new Command("About", Command.HELP, 106);
   private final Command exitCommand =
      new Command("Exit", Command.EXIT, 107);
   // debug screen
   private final Command backCommand =
      new Command("Back", Command.BACK, 1);
   private final Command startGCCommand =
      new Command("Start Garbage Collection", Command.SCREEN, 101);
   private final Command stopGCCommand =
      new Command("Stop Garbage Collection", Command.SCREEN, 102);

   // Softkeys to select a menu (assigned in startApp)
   private Command[] menuCmds;

   // The current menu
   private MenuData menu;

   // the array to hold the midlet in the toplevel folder
   private MidletInfo topLevelMidlets[];

   // "Main menu" screen
   private List menuScreen;
   private List debugScreen ;

   // "About" screen
   private final Alert aboutScreen =
      new Alert("About DemoMenu", aboutText, null, null);

   private String TOP_LEVEL_DIR_NAME = "/toplevel";

   // the following function reads the midlet information from the topLevel
   // folder and displays the menu.
   private void loadMidletsInTopLevel()
   {
       String[] jadFiles =
      FileService.getFilesWithExtension(TOP_LEVEL_DIR_NAME, "jad");
       String[] jadData = new String[jadFiles.length];
       int[] jadMidletCount = new int[jadFiles.length];
       String absDirPath;

       int i, count = 0;

       absDirPath = FileService.getRoot() + TOP_LEVEL_DIR_NAME;

       // Loop through all JAD files
       for (i = 0; i < jadFiles.length; i++)
       {
      RandomAccessStream stream = new RandomAccessStream();
      byte[] data = null;

      // Load JAD file contents
      try
      {
          stream.connect(absDirPath + "/" + jadFiles[i],
               Connector.READ);
          data = new byte[stream.getSizeOf()];
          stream.readBytes(data, 0, data.length);
          stream.disconnect();
      }
      catch (java.io.IOException e)
      {
      }

      if (data != null)
      {
          // Convert any Windows-style "\r\n" to plain "\n"
          // (This just improves the appearance when the
          // data is displayed.)
          int len = data.length;
          int n;
          for (n = 0; n < (len - 1); n++)
          {
         if ((data[n] == '\r') && (data[n+1] == '\n'))
         {
             len--;
             System.arraycopy(data, n + 1, data, n, len - n);
         }
          }

          // Store JAD file contents as String
          jadData[i] = new String(data, 0, len);

          // Count MIDlets in this JAD file
          int m;
          for (m = 1; jadData[i].indexOf("MIDlet-" + m + ":") >= 0; m++);
          jadMidletCount[i] = (m - 1);

          // Update total MIDlet count
          count += jadMidletCount[i];
      }
       }

       // Create new midlets array
       topLevelMidlets = new MidletInfo[count];

       // Fill midlets array
       int item = 0;
       for (i = 0; i < jadFiles.length; i++)
       {
      int midlet;
      for (midlet = 1; midlet <= jadMidletCount[i]; midlet++)
      {
          topLevelMidlets[item++] =
         new MidletInfo(absDirPath, jadFiles[i],
              jadData[i], midlet);
      }
       }
   }

   // Sets up and displays the given menu
   private void setupMenu(int menuIndex)
   {
      int i;

      // Get menu data associated with menuIndex
      menu = MenuData.getMenu(menuIndex);

      // Create new List screen to display menu on
      menuScreen = new List(menu.getName(), List.IMPLICIT);

      // Configure softkeys
      for (i = 0; i < menuCmds.length; i++)
      {
         menuScreen.addCommand(menuCmds[i]);
      }
      menuScreen.addCommand(externalCommand);
      menuScreen.addCommand(managerCommand);
      menuScreen.addCommand(introCommand);
      menuScreen.addCommand(aboutCommand);
      menuScreen.addCommand(tckModeCommand);
      menuScreen.addCommand(debugCommand);
      menuScreen.addCommand(exitCommand);
      menuScreen.setCommandListener(this);

      loadMidletsInTopLevel();
      for (i = 0; i < topLevelMidlets.length; i++)
      {
         menuScreen.append(topLevelMidlets[i].name,
            topLevelMidlets[i].icon);
      }
      // Append menu items
      for (i = 0; i < menu.getNumItems(); i++)
      {
         menuScreen.append(menu.getItemName(i), menu.getItemIcon(i));
      }


      // Display menu
      display.setCurrent(menuScreen);
   }

   // Schedules a midlet
   private void scheduleMidlet(String name, String classname,
                               boolean keepInBackground)
   {
      // Try to instantiate new MIDlet
      try
      {
         Scheduler.getScheduler().scheduleMIDlet(
            (MIDlet)(Class.forName(classname).newInstance()));
      }
      catch (Exception e)
      {
         // Create an error string
         String errorString =
            "Could not start " + name + ".\n\n" +
            "Error instantiating " + classname + "\n" +
            e.toString();

         // Create an "error" screen containing error message
         Alert errorScreen = new Alert("Error", errorString, null, null);

         // Go to "error" screen
         display.setCurrent(errorScreen, menuScreen);
         return;
      }

      if (keepInBackground)
      {
         // Put current MIDlet in background, allowing new one to run.
         display.setCurrent(null);
      }
      else
      {
         // Destroy this MIDlet, allowing new midlet to be scheduled instead
         destroyApp(true);
         notifyDestroyed();
      }
   }

   /**
    * Handles commands.
    */
   public void commandAction(Command c, Displayable s)
   {
      if (s == menuScreen)
      {
         if (c == externalCommand)
         {
            // Register this MIDlet as starting app to go back to when external
            // midlet browser exits, and external midlet browser as starting app
            // to go to when we exit right now.
            // Note:  The external midlet browser registers new apps and exits to
            // start them, so we cannot simply schedule the external midlet browser
            // from this midlet, but must register it as the starting app.
            Main.registerStartApp(getClass().getName(), null);
            Main.registerStartApp(MIDLET_BROWSER, null);

            // Exit this app to go to Manager
            destroyApp(true);
            notifyDestroyed();
         }
         else if (c == managerCommand)
         {
            // Register this MIDlet as starting app to go back to when Manager
            // exits, and Manager as starting app to go to when we exit right now.
            Main.registerStartApp(getClass().getName(), null);
            Main.registerStartApp(null, null);

            // Exit this app to go to Manager
            destroyApp(true);
            notifyDestroyed();
         }
         else if (c == introCommand)
         {
            // Instantiate Intro MIDlet in place of Menu MIDlet
            scheduleMidlet("Introduction", INTRO_MIDLET, false);
         }
         else if (c == aboutCommand)
         {
            // Go to "about" screen
            display.setCurrent(aboutScreen, menuScreen);
         }
         else if (c == exitCommand)
         {
            // Exit this app
            destroyApp(true);
            notifyDestroyed();
         }
         else if (c == tckModeCommand)
         {
            // Register this MIDlet as starting app to
            Main.registerStartApp(getClass().getName(), null);

            // Instantiate TCKMode Midlet in place of Menu Midlet
            scheduleMidlet("TCKMode", TCK_MODE_MIDLET, false);
         }
         else if (c == debugCommand)
         {
            display.setCurrent(debugScreen);
         }

         else if (c == List.SELECT_COMMAND)
         {
            // Get selected menu item
            int i = menuScreen.getSelectedIndex();

            // TBD - If we need to free up more memory for midlets, set the
            // keepInBackground parameter to false instead of true.
            // Register this MIDlet as starting app to
            Main.registerStartApp(getClass().getName(), null);

// 	 if (i < menu.getNumItems())
            if (i < topLevelMidlets.length)
            {
               MidletInfo selectedMidlet;
// 	     selectedMidlet = topLevelMidlets[i - menu.getNumItems()];
               selectedMidlet = topLevelMidlets[i];
               Main.registerStartApp(selectedMidlet.classname,
                                     selectedMidlet.dir + "/" +
                                     selectedMidlet.jadFile);

               // Exit this app
               destroyApp(true);
               notifyDestroyed();
            }
            else
            {
               // Set properties for selected menu item
               int n;
               for (n = 0;
                    n < menu.getItemNumProperties(i - topLevelMidlets.length);
                    n++)
               {
                  // TBD - This works for now, but when we add the MIDP
                  // security features we'll need to figure out how to
                  // get this MIDlet
                  // properly authorized to do this.
                  Scheduler.getScheduler().getMIDletSuite().addProperty
                  (
                  menu.getItemPropertyKey(i - topLevelMidlets.length, n),
                  menu.getItemPropertyValue(i - topLevelMidlets.length , n)
                  );
               }

               // Schedule selected MIDlet
               scheduleMidlet(menu.getItemName(i - topLevelMidlets.length),
                              menu.getItemClassname(i - topLevelMidlets.length),
                              false);
            }
         }
         else
         {
            // Find which menu was selected
            int i;
            for (i = 0; i < menuCmds.length; i++)
            {
               if (c == menuCmds[i])
               {
                  // Go to selected menu
               setupMenu(i);
               break;
            }
            }
         }
      }
      else if (s == debugScreen)
      {
         if (c == startGCCommand)
         {
            startGarbageCollection();
         }
         else if (c == stopGCCommand)
         {
            stopGarbageCollection();
         }
         else if (c == backCommand)
         {
            display.setCurrent(menuScreen);
         }

      }
   }

   /**
    * Starts the MIDlet.
    */
   public void startApp()
   {
      // Save display
      display = Display.getDisplay(this);

      // Set up menu softkeys
      menuCmds = new Command[MenuData.getNumMenus()];
      int i;
      for (i = 0; i < menuCmds.length; i++)
      {
         menuCmds[i] = new Command(MenuData.getMenu(i).getName(),
                                   Command.SCREEN, i);
      }

      // Go to main menu screen with first menu
      setupMenu(0);

      // set up debug menu
      debugScreen = new List("Debug", List.IMPLICIT);
      debugScreen.addCommand(backCommand);
      debugScreen.addCommand(startGCCommand);
      debugScreen.addCommand(stopGCCommand);
      debugScreen.setCommandListener(this);
   }

   /**
    * Prepares the MIDlet to be paused (and possibly later started again).
    */
   public void pauseApp()
   {
      // Nothing needs to be cleaned up for this MIDlet
   }

   /**
    * Prepares the MIDlet to be destroyed.
    */
   public void destroyApp(boolean unconditional)
   {
      // Nothing needs to be cleaned up for this MIDlet
   }

   private native int startGarbageCollection();
   private native int stopGarbageCollection();
}