Android应用开发之将SQLite和APK一起打包的方法

package com.test.db;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;

import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;

public class DbtestActivity extends Activity {
 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.main);

 // com.test.db 是程序的包名，请根据自己的程序调整
 // /data/data/com.test.db/
 // databases 目录是准备放 SQLite 数据库的地方，也是 Android 程序默认的数据库存储目录
 // 数据库名为 test.db
 String DB_PATH = "/data/data/com.test.db/databases/";
 String DB_NAME = "test.db";

 // 检查 SQLite 数据库文件是否存在
 if ((new File(DB_PATH + DB_NAME)).exists() == false) {
  // 如 SQLite 数据库文件不存在，再检查一下 database 目录是否存在
  File f = new File(DB_PATH);
  // 如 database 目录不存在，新建该目录
  if (!f.exists()) {
  f.mkdir();
  }

  try {
  // 得到 assets 目录下我们实现准备好的 SQLite 数据库作为输入流
  InputStream is = getBaseContext().getAssets().open(DB_NAME);
  // 输出流
  OutputStream os = new FileOutputStream(DB_PATH + DB_NAME);

  // 文件写入
  byte[] buffer = new byte[1024];
  int length;
  while ((length = is.read(buffer)) > 0) {
   os.write(buffer, 0, length);
  }

  // 关闭文件流
  os.flush();
  os.close();
  is.close();
  } catch (Exception e) {
  e.printStackTrace();
  }
 }

 // 下面测试 /data/data/com.test.db/databases/ 下的数据库是否能正常工作
 SQLiteDatabase database = SQLiteDatabase.openOrCreateDatabase(DB_PATH + DB_NAME, null);
 Cursor cursor = database.rawQuery("select * from test", null);

 if (cursor.getCount() > 0) {
  cursor.moveToFirst();
  try {
  // 解决中文乱码问题
  byte test[] = cursor.getBlob(0);
  String strtest = new String(test, "utf-8").trim();

  // 看输出的信息是否正确
  System.out.println(strtest);
  } catch (UnsupportedEncodingException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
  }
 }
 cursor.close();
 }
}

package zcping.syan.DBDefinition;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

import zcping.syan.DragonBaby.R;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;

public class ReleaseDataBaseActivity{
 /** Called when the activity is first created. */
 //SD卡下的目录
 private final String DATABASE_PATH = android.os.Environment
  .getExternalStorageDirectory().getAbsolutePath() + "/db_exam";
 //数据库名
 private final String DATABASE_FILENAME = "db_exam.db";
 //这个context是必需的，没有context，怎么都不能实现数据库的拷贝操作；
 private Context context;
 //构造函数必需传入Context，数据库的操作都带有这个参数的传入
 public ReleaseDataBaseActivity(Context ctx) {
 this.context = ctx;
 }

 public SQLiteDatabase OpenDataBase() {
 try {
  String databaseFilename = DATABASE_PATH + "/" + DATABASE_FILENAME;
  File dir = new File(DATABASE_PATH);
  //判断SD卡下是否存在存放数据库的目录，如果不存在，新建目录
  if (!dir.exists()) {
  dir.mkdir();
  Log.i("ReleaseDataBaseActivity", "dir made:" + DATABASE_PATH);
  } else {
  Log.i("ReleaseDataBaseActivity", "dir exist:" + DATABASE_PATH);
  }
  try {
  //如果数据库已经在SD卡的目录下存在，那么不需要重新创建，否则创建文件，并拷贝/res/raw下面的数据库文件
  if (!(new File(databaseFilename)).exists()) {
   Log.i("ReleaseDataBaseActivity", "file not exist:"
    + databaseFilename);
   ///res/raw数据库作为输出流
   InputStream is = this.context.getResources().openRawResource(
    R.raw.db_exam);
   //测试用
   int size = is.available();
   Log.i( "ReleaseDataBaseActivity", "DATABASE_SIZE:" + 1 );
   Log.i("ReleaseDataBaseActivity", "count:" + 0);
   //用于存放数据库信息的数据流
   FileOutputStream fos = new FileOutputStream(
    databaseFilename);
    byte[] buffer = new byte[8192];
   int count = 0;
   Log.i("ReleaseDataBaseActivity", "count:" + count);
   //把数据写入SD卡目录下
   while ((count = is.read(buffer)) > 0) {
   fos.write(buffer, 0, count);
   }
   fos.flush();
   fos.close();
   is.close();
  }
  } catch (FileNotFoundException e) {
  Log.e("Database", "File not found");
  e.printStackTrace();
  } catch (IOException e) {
  Log.e("Database", "IO exception");
  e.printStackTrace();
  }
  //实例化sd卡上得数据库，database作为返回值，是后面所有插入，删除，查询操作的借口。
  SQLiteDatabase database = SQLiteDatabase.openOrCreateDatabase(
   databaseFilename, null);
  return database;

 } catch (Exception e) {
 }
 return null;
 }
}