/* * Copyright (C) 2008 Google Inc. *  * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at *  * http://www.apache.org/licenses/LICENSE-2.0 *  * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */package com.android.demo.notepad1;import android.content.ContentValues;import android.content.Context;import android.database.Cursor;import android.database.SQLException;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;import android.util.Log;/** * Simple notes database access helper class. Defines the basic CRUD operations * for the notepad example, and gives the ability to list all notes as well as * retrieve or modify a specific note. *  * This has been improved from the first version of this tutorial through the * addition of better error handling and also using returning a Cursor instead * of using a collection of inner classes (which is less scalable and not * recommended). */public class NotesDbAdapter {    public static final String KEY_TITLE = "title";    public static final String KEY_BODY = "body";    public static final String KEY_ROWID = "_id";    private static final String TAG = "NotesDbAdapter";    private DatabaseHelper mDbHelper;    private SQLiteDatabase mDb;        /**     * Database creation sql statement     */    private static final String DATABASE_CREATE =            "create table notes (_id integer primary key autoincrement, "                    + "title text not null, body text not null);";    private static final String DATABASE_NAME = "data";    private static final String DATABASE_TABLE = "notes";    private static final int DATABASE_VERSION = 2;    private final Context mCtx;    private static class DatabaseHelper extends SQLiteOpenHelper {        DatabaseHelper(Context context) {            super(context, DATABASE_NAME, null, DATABASE_VERSION);        }        @Override        public void onCreate(SQLiteDatabase db) {            db.execSQL(DATABASE_CREATE);        }        @Override        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {            Log.w(TAG, "Upgrading database from version " + oldVersion + " to "                    + newVersion + ", which will destroy all old data");            db.execSQL("DROP TABLE IF EXISTS notes");            onCreate(db);        }    }    /**     * Constructor - takes the context to allow the database to be     * opened/created     *      * @param ctx the Context within which to work     */    public NotesDbAdapter(Context ctx) {        this.mCtx = ctx;    }    /**     * Open the notes database. If it cannot be opened, try to create a new     * instance of the database. If it cannot be created, throw an exception to     * signal the failure     *      * @return this (self reference, allowing this to be chained in an     *         initialization call)     * @throws SQLException if the database could be neither opened or created     */    public NotesDbAdapter open() throws SQLException {        mDbHelper = new DatabaseHelper(mCtx);        mDb = mDbHelper.getWritableDatabase();        return this;    }        public void close() {        mDbHelper.close();    }    /**     * Create a new note using the title and body provided. If the note is     * successfully created return the new rowId for that note, otherwise return     * a -1 to indicate failure.     *      * @param title the title of the note     * @param body the body of the note     * @return rowId or -1 if failed     */    public long createNote(String title, String body) {        ContentValues initialValues = new ContentValues();        initialValues.put(KEY_TITLE, title);        initialValues.put(KEY_BODY, body);        return mDb.insert(DATABASE_TABLE, null, initialValues);    }    /**     * Delete the note with the given rowId     *      * @param rowId id of note to delete     * @return true if deleted, false otherwise     */    public boolean deleteNote(long rowId) {        return mDb.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;    }    /**     * Return a Cursor over the list of all notes in the database     *      * @return Cursor over all notes     */    public Cursor fetchAllNotes() {        return mDb.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_TITLE,                KEY_BODY}, null, null, null, null, null);    }    /**     * Return a Cursor positioned at the note that matches the given rowId     *      * @param rowId id of note to retrieve     * @return Cursor positioned to matching note, if found     * @throws SQLException if note could not be found/retrieved     */    public Cursor fetchNote(long rowId) throws SQLException {        Cursor mCursor =                mDb.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,                        KEY_TITLE, KEY_BODY}, KEY_ROWID + "=" + rowId, null,                        null, null, null, null);        if (mCursor != null) {            mCursor.moveToFirst();        }        return mCursor;    }    /**     * Update the note using the details provided. The note to be updated is     * specified using the rowId, and it is altered to use the title and body     * values passed in     *      * @param rowId id of note to update     * @param title value to set note title to     * @param body value to set note body to     * @return true if the note was successfully updated, false otherwise     */    public boolean updateNote(long rowId, String title, String body) {        ContentValues args = new ContentValues();        args.put(KEY_TITLE, title);        args.put(KEY_BODY, body);        return mDb.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;    }}