mainscreen.java~48~

基于j2me编写的小型英汉汉词典

package org.zblog.zenghelper.screen;

import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.Displayable;
import org.zblog.zenghelper.util.Navigator;
import javax.microedition.lcdui.List;
import javax.microedition.lcdui.Choice;
import org.zblog.zenghelper.util.PublicRes;

/**
 * <p>Title: MainScreen</p>
 *
 * <p>Description: Z英汉词典</p>
 *
 * <p>Copyright: Zcw Copyright (c) 2004</p>
 *
 * <p>Company: www.zblog.org Z动力</p>
 *
 * @author 朱传伟-ZCW
 * @version 1.0
 */
public class MainScreen extends List implements CommandListener{
    private static Displayable instance=null;
    public MainScreen(){
        super("英语学习助手",Choice.IMPLICIT);
        PublicRes pr=PublicRes.getInstance();
        append(" 英汉查询",pr.selImage);
        append(" 添加单词",pr.selImage);
        append(" 生词卡片",pr.selImage);
        append(" 系统设置",pr.selImage);
        append(" 版权帮助",pr.selImage);
        addCommand(new Command("确定",Command.OK,1));
        addCommand(new Command("退出",Command.EXIT,1));
        this.setCommandListener(this);
    }

    /**
     * 返回主页面对象
     * @return Displayable
     */
    public synchronized static Displayable getInstance(){
        if(instance==null)
            instance=new MainScreen();
        return instance;
    }

    /**
     * 监听主页面中的＂确定＂，＂退出＂，＂select＂命令.
     * <br>１．＂确定＂命令可以进入用户选择的选项
     * <br>２．＂select＂命令也可以进入用户选择的选项
     * <br>３．＂退出＂命令将退出程序
     * @param command Command
     * @param displayable Displayable
     */
    public void commandAction(Command command, Displayable displayable) {
        String id=command.getLabel();
        if(id.equals("确定")){
            int i=getSelectedIndex();
            //由于在Navigator中是从1开始编号，并且1被Main_Screen占用，所以需要+2
            Navigator.current=i+2;
            System.out.println("-"+Navigator.current+"-");
            Navigator.show();
        }
        if(command==List.SELECT_COMMAND){
            int i=getSelectedIndex();
            Navigator.current=i+2;
            Navigator.show();
        }
        if(id.equals("退出")){
            Navigator.exitSystem();
        }

    }

}