package com.sin.android.database; import java.io.File; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import java.util.HashMap; import java.util.Map; import android.content.Context; import android.content.SharedPreferences; import android.content.res.AssetManager; import android.database.sqlite.SQLiteDatabase; import android.util.Log; /**  * This is a Assets Database Manager  * Use it, you can use a assets database file in you application  * It will copy the database file to "/data/data/[your application package name]/database" when you first time you use it  * Then you can get a SQLiteDatabase object by the assets database file * @author RobinTang  * @time 2012-09-20  *  *  * How to use:  * 1. Initialize AssetsDatabaseManager  * 2. Get AssetsDatabaseManager  * 3. Get a SQLiteDatabase object through database file  * 4. Use this database object  *  * Using example:  * AssetsDatabaseManager.initManager(getApplication()); // this method is only need call one time  * AssetsDatabaseManager mg = AssetsDatabaseManager.getManager();  // get a AssetsDatabaseManager object  * SQLiteDatabase db1 = mg.getDatabase("db1.db");  // get SQLiteDatabase object, db1.db is a file in assets folder  * db1.??? // every operate by you want  * Of cause, you can use AssetsDatabaseManager.getManager().getDatabase("xx") to get a database when you need use a database  */ public class AssetsDatabaseManager {   private static String tag = "AssetsDatabase"; // for LogCat   private static String databasepath = "/data/data/%s/database"; // %s is packageName   // A mapping from assets database file to SQLiteDatabase object   private Map<String, SQLiteDatabase> databases = new HashMap<String, SQLiteDatabase>();   // Context of application   private Context context = null;   // Singleton Pattern   private static AssetsDatabaseManager mInstance = null;   /**    * Initialize AssetsDatabaseManager    * @param context, context of application    */   public static void initManager(Context context){     if(mInstance == null){       mInstance = new AssetsDatabaseManager(context);     }   }   /**    * Get a AssetsDatabaseManager object    * @return, if success return a AssetsDatabaseManager object, else return null    */   public static AssetsDatabaseManager getManager(){     return mInstance;   }   private AssetsDatabaseManager(Context context){     this.context = context;   }   /**    * Get a assets database, if this database is opened this method is only return a copy of the opened database    * @param dbfile, the assets file which will be opened for a database    * @return, if success it return a SQLiteDatabase object else return null    */   public SQLiteDatabase getDatabase(String dbfile) {     if(databases.get(dbfile) != null){       Log.i(tag, String.format("Return a database copy of %s", dbfile));       return (SQLiteDatabase) databases.get(dbfile);     }     if(context==null)       return null;     Log.i(tag, String.format("Create database %s", dbfile));     String spath = getDatabaseFilepath();     String sfile = getDatabaseFile(dbfile);     File file = new File(sfile);     SharedPreferences dbs = context.getSharedPreferences(AssetsDatabaseManager.class.toString(), 0);     boolean flag = dbs.getBoolean(dbfile, false); // Get Database file flag, if true means this database file was copied and valid    if(!flag || !file.exists()){       file = new File(spath);       if(!file.exists() && !file.mkdirs()){         Log.i(tag, "Create /""+spath+"/" fail!");         return null;       }       if(!copyAssetsToFilesystem(dbfile, sfile)){         Log.i(tag, String.format("Copy %s to %s fail!", dbfile, sfile));         return null;       }       dbs.edit().putBoolean(dbfile, true).commit();     }     SQLiteDatabase db = SQLiteDatabase.openDatabase(sfile, null, SQLiteDatabase.NO_LOCALIZED_COLLATORS);     if(db != null){       databases.put(dbfile, db);     }     return db;   }   private String getDatabaseFilepath(){     return String.format(databasepath, context.getApplicationInfo().packageName);   }   private String getDatabaseFile(String dbfile){     return getDatabaseFilepath()+"/"+dbfile;   }   private boolean copyAssetsToFilesystem(String assetsSrc, String des){     Log.i(tag, "Copy "+assetsSrc+" to "+des);     InputStream istream = null;     OutputStream ostream = null;     try{       AssetManager am = context.getAssets();       istream = am.open(assetsSrc);       ostream = new FileOutputStream(des);       byte[] buffer = new byte[1024];       int length;       while ((length = istream.read(buffer))>0){         ostream.write(buffer, 0, length);       }       istream.close();       ostream.close();     }     catch(Exception e){       e.printStackTrace();       try{         if(istream!=null)           istream.close();         if(ostream!=null)           ostream.close();       }       catch(Exception ee){         ee.printStackTrace();       }       return false;     }     return true;   }   /**    * Close assets database    * @param dbfile, the assets file which will be closed soon    * @return, the status of this operating    */   public boolean closeDatabase(String dbfile){     if(databases.get(dbfile) != null){       SQLiteDatabase db = (SQLiteDatabase) databases.get(dbfile);      db.close();       databases.remove(dbfile);       return true;     }     return false;   }   /**    * Close all assets database    */   static public void closeAllDatabase(){     Log.i(tag, "closeAllDatabase");     if(mInstance != null){       for(int i=0; i<mInstance.databases.size(); ++i){         if(mInstance.databases.get(i)!=null){           mInstance.databases.get(i).close();         }       }       mInstance.databases.clear();     }   } } 

// 初始化，只需要調用一次 AssetsDatabaseManager.initManager(getApplication()); // 獲取管理對象，因為數據庫需要通過管理對象才能夠獲取 AssetsDatabaseManager mg = AssetsDatabaseManager.getManager(); // 通過管理對象獲取數據庫 SQLiteDatabase db1 = mg.getDatabase("db1.db"); // 對數據庫進行操作 db1.execSQL("insert into tb([ID],[content]) values(null, 'db1');");