SQLite (part deux) 1 CS440

Traditional Model View Controller (MVC) CS440 2

Android: Database-centric data CS440 3

Useful classes  SQLiteDatabase is the base class for working with a SQLite database in Android. Methods:  open  query: rawQuery(), execSQL()  update  close CS440 4 Cursor cursor = getReadableDatabase(). rawQuery("select * from todo where _id = ?", new String[] { id });

Cursor  A query returns a Cursor object  Cursor can represent many objects (multiple lines)  A Cursor points to one row of the query result  You can move between multiple lines with Cursor.moveToNext()  Useful methods:  getCount()  moveToFirst(), moveToNext(), moveToPrevious()  isAfterLast()  getAs*(): eg. getAsString(int columnNumber) 5

ListViews, ListActivities, and SimpleCursorAdapter  ListViews : Views which allow to display a list of elements  ListActivities : specialized Activities which make the usage of ListViews easier  SimpleCursorAdapter : maps the columns to the Views based on the Cursor passed to it CS440 6

SQLiteOpenHelper  Provides lifecycle framework for creating and upgrading your application database  Useful methods:  String getDatabaseName()  void onOpen(SQLiteDatabase db)  abstract void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)  More on: database/sqlite/SQLiteOpenHelper.html database/sqlite/SQLiteOpenHelper.html CS440 7

SQLiteQueryBuilder  High level abstraction for creating SQL queries  Useful Methods:  Cursor query(SQLiteDatabase db, String[] projectionIn, String s election, String[] selectionArgs, String groupBy, String h aving, String sortOrder)SQLiteDatabaseString[]StringString[]String Perform a query by combining all current settings and the information passed into this method.  String buildQuery(boolean distinct, String tables, String[] columns, String where, Stri ng groupBy, String having, String orderBy, String limit)StringString[]StringStri ngString CS440 8

References  Oreilly, Programming Android, Mednieks, Dornin CS440 9