record.java

手机版本的泡泡堂 用j2me写的 大家可以参考下

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import javax.microedition.rms.RecordStore;

/***
 * 类名：Record
 * 功能：在RMS中存储游戏中玩家的名字和得分
 */
public final class Record
{
    public int MAXSIZE;
    private RecordStore rs;
    private String recordName;
    public String name;
    public long score;

    public Record(String recordName, int maxsize)
    {
        this.recordName = recordName;
        MAXSIZE = maxsize;
        score = 0;
        name = "AAAA";
    }

    /**
     * 打开指定的RMS。
     */
    public final void openRecordStore(boolean createIfNecessary)
            throws Exception
    {
        rs = RecordStore.openRecordStore(recordName, createIfNecessary);
    }

    public final void closeRecordStore() throws Exception
    {
        rs.closeRecordStore();
    }

    /**
     * 合成数据；
     * */
    private final byte[] encode() throws Exception
    {
        byte[] result;
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        DataOutputStream dos = new DataOutputStream(bos);
        dos.writeUTF(name);
        dos.writeLong(score);
        result = bos.toByteArray();
        dos.close();
        bos.close();
        return result;
    }

    /**
     * 分解数据；
     * */
    private final void decode(byte[] data) throws Exception
    {
        ByteArrayInputStream bis = new ByteArrayInputStream(data);
        DataInputStream dis = new DataInputStream(bis);
        name = dis.readUTF();
        score = dis.readLong();
        dis.close();
        bis.close();
    }

    /**
     * 当前成绩和最后一条记录的成绩比较；默认排序方式为降序；
     * */
    private final boolean isSave(long score) throws Exception
    {
        byte[] temp = rs.getRecord(MAXSIZE);
        decode(temp);
        if (score > this.score)
        {
            return true;
        }
        return false;
    }

    /**
     * 保存得分记录前，对以前的记录进行比较；若得分比以前得分高，才保存记录；
     * */
    public final void saveScore(String name, long score)
    {
        try
        {
            openRecordStore(false);
            if (isSave(score))
            {
                this.name = name;
                this.score = score;
                byte[] temp;
                temp = encode();
                rs.setRecord(MAXSIZE + 1, temp, 0, temp.length);
                insertRecord(score);
            }
            closeRecordStore();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

    /**插入记录*/
    private final void insertRecord(long score) throws Exception
    {
        byte[] temp, inserdata, currentdata;
        inserdata = rs.getRecord(MAXSIZE + 1);//需要插入的记录
        long currentscore;
        String currentname;
        for (int i = 1; i <= MAXSIZE;)
        {
            currentdata = rs.getRecord(i);
            ByteArrayInputStream bis = new ByteArrayInputStream(currentdata);
            DataInputStream dis = new DataInputStream(bis);
            currentname = dis.readUTF();
            currentscore = dis.readLong();
            if (score < currentscore)
            {
                i++;
            }
            else
            {
                temp = currentdata;
                rs.setRecord(i, inserdata, 0, inserdata.length);
                for (int j = i; j <= MAXSIZE; j++)
                {
                    currentdata = rs.getRecord(j + 1);
                    rs.setRecord(j + 1, temp, 0, temp.length);
                    temp = currentdata;
                }
                return;
            }
        }
    }

    /**
     * 显示记录；
     *     进入排行榜界面时 openRecordStore（）；
     *     返回菜单界面时  closeRecordStore（）；
     * */
    public final void loadScore(int recordID)
    {
        if (recordID <= MAXSIZE)
        {
            try
            {
                byte[] temp = rs.getRecord(recordID);
                decode(temp);
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
        }
    }

    /**
     * 添加MAXSIZE + 1条默认成绩的记录
     * */
    public final void addDefaultRecord()
    {
        try
        {
            openRecordStore(true);
            if (rs.getNumRecords() == 0)
            {
                byte[] temp = encode();
                for (int i = 1; i <= MAXSIZE + 1; i++)
                {
                    rs.addRecord(temp, 0, temp.length);
                }
            }
            closeRecordStore();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }
}