gamerecord.java

一个J2ME编译的打地鼠小游戏,供初学者学习

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import javax.microedition.lcdui.Font;
import javax.microedition.lcdui.Graphics;
import javax.microedition.rms.InvalidRecordIDException;
import javax.microedition.rms.RecordStore;
import javax.microedition.rms.RecordStoreException;
import javax.microedition.rms.RecordStoreFullException;
import javax.microedition.rms.RecordStoreNotFoundException;
import javax.microedition.rms.RecordStoreNotOpenException;

/**
 *   游戏存储RMS
 * @author univasity
 *
 */
public class GameRecord {
	private final int MAXRECORD = 3;  //最大存储量
    private RecordStore rs;
    private DataInputStream dis;
    private DataOutputStream dos;
    private ByteArrayOutputStream baos;
    private String rc_name;
    
    GameRecord(String name){
    	try {
    		rc_name = name;
			rs = RecordStore.openRecordStore(rc_name, true);  //打开记录仓储
			if(rs.getNumRecords()==0){   //如果为新仓储，则初始化它
				byte[] test = toByte("",0);
				for(int i=0; i<MAXRECORD; i++)
				    rs.addRecord(test, 0, test.length);
			}
		    release();
		} catch (RecordStoreFullException e) {
			e.printStackTrace();
		} catch (RecordStoreNotFoundException e) {
			e.printStackTrace();
		} catch (RecordStoreException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
    }
    /**
     * 添加记录
     * @param name 姓名
     * @param score 分数
     * @throws RecordStoreNotOpenException
     * @throws RecordStoreFullException
     * @throws RecordStoreException
     * @throws IOException 
     */
    public void addRecord(String name,int score) throws RecordStoreNotOpenException, RecordStoreFullException, RecordStoreException, IOException{
    	rs = RecordStore.openRecordStore(rc_name, true);  //打开记录仓储
    	if(rs!=null){
    		if(isNewRecord(score)){
    			byte[] rc_data = toByte(name,score);  //把需要存入的数据转换好
        		if(rs.getNumRecords()<MAXRECORD){
        		    rs.addRecord(rc_data, 0, rc_data.length);
        		}else{
        			rs.setRecord(MAXRECORD, rc_data, 0, rc_data.length);
        		}
        		sortRecord();  //记录排序
    		}
    	}
    	release();
    }
    /**
     * 排序 - 由大到小整理记录
     * @throws RecordStoreException 
     * @throws InvalidRecordIDException 
     * @throws RecordStoreNotOpenException 
     */
    public void sortRecord() throws RecordStoreNotOpenException, InvalidRecordIDException, RecordStoreException {
		for(int out=rs.getNumRecords(); out>1; out--){
			for(int i=1; i<out; i++){
				byte[] a = rs.getRecord(i);
				byte[] b = rs.getRecord(i+1);
				if(byteToInt(a)<byteToInt(b)){
					rs.setRecord(i, b, 0, b.length);
					rs.setRecord(i+1, a, 0, a.length);
				}
			}
		}
	}

	/**
	 * 显示记录
	 * @param g 画笔
	 * @param w 屏幕宽
	 * @param h 屏幕高
	 * @param x 显示的首坐标x
	 * @param y 显示的首坐标y
	 * @param x_border 名字与分数的间距
	 * @param y_border 行与行的间距
	 * @param color 字体颜色
	 * @param font 字体类型
	 * @throws RecordStoreNotOpenException
	 * @throws InvalidRecordIDException
	 * @throws RecordStoreException
	 * @throws IOException
	 */
    public void showRecord(Graphics g,int w,int h,int x,int y,int x_border,int y_border,int color,Font font) throws RecordStoreNotOpenException, InvalidRecordIDException, RecordStoreException, IOException{
    	g.setClip(0, 0, w, h);
    	g.setColor(color);
    	if(font!=null)
    		g.setFont(font);
    	//信息
    	g.drawString("名字", x, y, 20);
    	g.drawString("分数", x+x_border, y, 20);
    	y+=h/16;
    	rs = RecordStore.openRecordStore(rc_name, false);  //打开记录仓储
    	for(int i=1; i<=MAXRECORD; i++){
    		dis = new DataInputStream(new ByteArrayInputStream(rs.getRecord(i)));
    		g.drawString(dis.readUTF(), x, y+y_border*(i-1), 20);
    		g.drawString(""+dis.readInt(), x+x_border, y+y_border*(i-1), 20);
    		dis.close();
    	}
    	release();
    }
    /**
     * 将数据转换为字节数组
     * @param str
     * @return
     */
    private byte[] toByte(String str,int n){
    	dos = new DataOutputStream(baos = new ByteArrayOutputStream());
    	try {
			dos.writeUTF(str);
			dos.writeInt(n);
			dos.flush();
			dos.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
    	byte[] temp = baos.toByteArray();
    	return temp;
    }
    /**
     *  是否为新记录
     * @param score 新记录
     * @return
     * @throws RecordStoreException 
     * @throws InvalidRecordIDException 
     * @throws RecordStoreNotOpenException 
     * @throws IOException 
     */
    public boolean isNewRecord(int score) throws RecordStoreNotOpenException, InvalidRecordIDException, RecordStoreException, IOException{
    	rs = RecordStore.openRecordStore(rc_name, false);  //打开记录仓储
    	int temp = byteToInt(rs.getRecord(rs.getNumRecords()));  //读取最后一条记录
    	release();  //释放资源
    	if(score>temp)
    		return true;
    	else
    		return false;
    }
    /**
     *  字节数组到整数的转换
     * @param bt 需要转换的数据
     * @return
     */
    private int byteToInt(byte[] bt){
    	dis = new DataInputStream(new ByteArrayInputStream(bt));
    	int n = -1;
    	try {
    		dis.readUTF();
			n = dis.readInt();
			dis.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return n;
    }
    
    /**
     * 释放资源
     * @throws RecordStoreNotOpenException
     * @throws RecordStoreException
     * @throws IOException
     */
    public void release() throws RecordStoreNotOpenException, RecordStoreException, IOException{
    	if(dis!=null)
    		dis.close();
    	if(dos!=null)
    		dos.close();
    	if(rs!=null)
    	    rs.closeRecordStore();
    }
}