rmstest.java

几个不错的手机程序例子

/*
 * RMSTest.java
 *
 * Copyright 2001 SkyArts. All Rights Reserved.
 */
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import java.util.Calendar;
import java.util.Date;
import java.util.Vector;
import javax.microedition.rms.*;


/**
 * Record Management System(RMS)记录的添加、删除、改变的范例的MIDlet
 *
 * @author  Hideki Yonekawa
 * @version 1.0
 */
public class RMSTest extends MIDlet implements CommandListener {
	/** 显示记录一览的List变量 */
	private List				recordList;

	/** 保持记录的ID的Vector。与记录的一览List相同顺序 */
	private Vector				idVect				= new Vector();

	/** 删除命令 */
	private Command				delCmd			= new Command("删除", Command.SCREEN, 1);
	/** 添加命令 */
	private Command				addCmd			= new Command("添加", Command.SCREEN, 5);

	/** 储存RecordStore名称的常量 */
	private static final String RS_NAME				= "RMSTest";

	/** 储存用以取得时间的Calendar对象的常量 */
	private Calendar			calendar;

	/** 构造函数 */
	public RMSTest() {
		//取得Calendar对象
		calendar = Calendar.getInstance();

		//制作记录的一览表List
		createRecordList();

		//显示记录的List
		Display.getDisplay(this).setCurrent(recordList);
	}

	/** MIDlet开始时调用的方法 */
	protected void startApp() throws MIDletStateChangeException {}

	/** MIDlet暂停时调用的方法 */
	protected void pauseApp() {}

	/** MIDlet结束时调用的方法 */
	protected void destroyApp(boolean unconditional)
								throws MIDletStateChangeException {}

	/** 制作记录一览表List的方法 */
	private void createRecordList() {
		//建立记录List
		recordList = new List("记录一览表", Choice.IMPLICIT);
		//附加记录
		recordList.addCommand(delCmd);
		recordList.addCommand(addCmd);
		recordList.setCommandListener(this);

		RecordStore rs = null;
		try {
			//清除储存ID的Vector
			idVect.removeAllElements();
			//打开RecordStore
			rs = RecordStore.openRecordStore(RS_NAME, true);

			//取得记录的Enumeration
			RecordEnumeration recordEnumeration = rs.enumerateRecords(null, null, true);
			while(recordEnumeration.hasNextElement()) {
				//取得Enumeration中的记录ID
				int id = recordEnumeration.nextRecordId();
				//以ID取得byte数组写成String
				String tmpSt = new String(rs.getRecord(id));
				//在储存ID的Vector添加ID
				idVect.addElement(new Integer(id));
				//在记录的List中增加字符串
				recordList.append(tmpSt, null);
			}
		}catch(RecordStoreException e) {
		}finally {
			if(rs != null) {
				try {
					//关闭RecordStore
					rs.closeRecordStore();
				}catch(RecordStoreException ex) {}
			}
		}
	}

	/**
	 * Command的事件发生时
	 * 选择List时调用的方法
	 */
	public void commandAction(Command c, Displayable d) {
		if(d == recordList) {					//显示记录的List时
			if(c == List.SELECT_COMMAND) {			//选择List时
				if(recordList.getSelectedIndex() < 0) return;

				//改变被选择的记录
					doSave(recordList.getSelectedIndex(), getTimeSt());
					createRecordList();
			}else {						//List没被选择时
				if(c == delCmd) {			//选择删除命令时
					if(recordList.getSelectedIndex() < 0) return;

					//从选择的List的Index将记录删除
					doDelete(recordList.getSelectedIndex());
				}else if(c == addCmd) {			//选择添加命令时
					doSave(-1, getTimeSt());
					createRecordList();
				}
			}
			//显示记录的List
			Display.getDisplay(this).setCurrent(recordList);
		}
	}

	/** 以指定的Index与文字来添加、更新、删除命令的方法 */
	private boolean doSave(int inx, String writeSt) {
		//更新处理
		RecordStore rs = null;
		try {
			//打开RecordStore
			rs = RecordStore.openRecordStore(RS_NAME, true);
			if(inx < 0) {						//制作新记录时
				//确认可储存的容量大小
				int availableSize = rs.getSizeAvailable();
				byte[] writeBytes = writeSt.getBytes();
				if(availableSize >= writeBytes.length) {	//未超过容量大小时
					//为了重做List而将ID写到Vector
					//添加记录。在添加时传回的ID先写在储存ID的Vector中
					int id = rs.addRecord(writeBytes, 0, writeBytes.length);
					idVect.addElement(new Integer(id));
				}else {						//超过容量大小时
					return false;
				}
			}else {							//变更时
				//从储存ID的Vector取得该ID
				int id = ((Integer)idVect.elementAt(inx)).intValue();
				if(writeSt.length() > 0) {			//有文字时
					//更新记录
					byte[] writeBytes = writeSt.getBytes();
					rs.setRecord(id, writeBytes, 0, writeBytes.length);
				}else {						//没有文字时
					//删除记录
					rs.deleteRecord(id);
				}
			}
		}catch(RecordStoreException e) {
		}finally {
			if(rs != null) {
				try {
					//关闭RecordStore
					rs.closeRecordStore();
				}catch(RecordStoreException ex) {}
			}
		}
		return true;
	}

	/** 将指定Index的记录删除的方法 */
	private void doDelete(int inx) {
		//调用doSave方法,将记录删除
		doSave(inx, "");
		recordList.delete(inx);
		idVect.removeElementAt(inx);
	}

	/** 传回表示现在时间的字符串 */
	private String getTimeSt() {
		calendar.setTime(new Date());
		StringBuffer stBuffer = new StringBuffer();
		stBuffer.append(String.valueOf(calendar.get(Calendar.HOUR_OF_DAY)) +":");	//时
		stBuffer.append(String.valueOf(calendar.get(Calendar.MINUTE)) +" ");		//分
		stBuffer.append(String.valueOf(calendar.get(Calendar.SECOND)));			//秒
		return stBuffer.toString();
	}
}