拷贝已有数据到/data/data/co.test/databases/目录

public class DatabaseHelper extends SQLiteOpenHelper{
	private static String DB_PATH = "/data/data/co.test/databases/";
    private static String DB_NAME = "test";
    private SQLiteDatabase myDataBase; 
    private final Context myContext;
    
    public DatabaseHelper(Context context) {
     	super(context, DB_NAME, null, 1);
        this.myContext = context;
    }	
     
    /**
     * Creates a empty database on the system and rewrites it with your own database.
     * */
    public void createDataBase() throws IOException{
    	boolean dbExist = checkDataBase();
    	if(dbExist){
    		//do nothing - database already exist
    	}else{
    		//By calling this method and empty database will be created into the default system path
               //of your application so we are gonna be able to overwrite that database with our database.
        	this.getReadableDatabase();
       	try {
    			copyDataBase();
    		} catch (IOException e) {
         		throw new Error("Error copying database");
         	}
    	}
     }

    /**
     * Check if the database already exist to avoid re-copying the file each time you open the application.
     * @return true if it exists, false if it doesn't
     */
    private boolean checkDataBase(){
     	SQLiteDatabase checkDB = null;
     	try{
    		String myPath = DB_PATH + DB_NAME;
    		checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
     	}catch(SQLiteException e){
     		//database does't exist yet.
     		throw new Error("Database does't exist yet.");
     	}
     	if(checkDB != null){
     		checkDB.close();
     	}
     	return checkDB != null ? true : false;
    }
 
    /**
     * Copies your database from your local assets-folder to the just created empty database in the
     * system folder, from where it can be accessed and handled.
     * This is done by transfering bytestream.
     * */
    private void copyDataBase() throws IOException{
     	//Open your local db as the input stream
    	InputStream myInput = myContext.getAssets().open(DB_NAME);
     	// Path to the just created empty db
    	String outFileName = DB_PATH + DB_NAME;
     	//Open the empty db as the output stream
    	OutputStream myOutput = new FileOutputStream(outFileName);
     	//transfer bytes from the inputfile to the outputfile
    	byte[] buffer = new byte[1024];
    	int length;
    	while ((length = myInput.read(buffer))>0){
    		myOutput.write(buffer, 0, length);
    	}
     	//Close the streams
    	myOutput.flush();
    	myOutput.close();
    	myInput.close();
     }

    @Override
	public synchronized void close() {
     	    if(myDataBase != null)
    		    myDataBase.close();
     	    super.close();
 	}
 
    @Override
	public void onCreate(SQLiteDatabase db) {
 	}
	
    @Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
 	}

    public void openDataBase() throws SQLException{
    	 
    	//Open the database
        String myPath = DB_PATH + DB_NAME;
    	myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
 
    }

}