在android项目里使用自带的SQLite数据库

//The Android's default system path of your application database.

    private static String DB_PATH = "/data/data/你的项目package/databases/";

 

    private static String DB_NAME = "数据库名称";

 

    private SQLiteDatabase myDataBase; 

 

    private final Context myContext;

 

    /**

     * Constructor

     * Takes and keeps a reference of the passed context in order to access to the application assets and resources.

     * @param context

     */

    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.

 

        }

 

        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();

 

    }

 

    public void openDataBase() throws SQLException{

 

        //Open the database

        String myPath = DB_PATH + DB_NAME;

        myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

 

    }

 

    @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) {

 

    }

 

        // Add your public helper methods to access and get content from the database.

       // You could return cursors by doing "return myDataBase.query(....)" so it'd be easy

       // to you to create adapters for your views.}