Monday, May 28, 2012

Content Provider Example - 2

Implement the business login in the override methods.
   
    Using the onCreate Method we can initilze the Database
        @Override
        public boolean onCreate() {
            Context context = getContext();
            SQLiteConnectionManager dbHelper = new SQLiteConnectionManager(context);
            demoDB = dbHelper.getWritableDatabase();
            return (demoDB == null) ? false : true;
        }

    getType method is used to validate the input url
        @Override
        public String getType(Uri uri) {
            switch (uriMatcher.match(uri)) {
            case UserInfo.USERINFO:
                return UserInfo.CONTENT_TYPE;
            case UserInfo.USERINFO_ID:
                return UserInfo.CONTENT_ITEM_TYPE;
            default:
                throw new IllegalArgumentException("Unsupported URI: " + uri);
            }
        }


    CRUD Operation

    Create - insert()
        long rowID = demoDB.insert(UserInfo.DATABASE_TABLE, "", values);
        if (rowID > 0) {
            Uri _uri = ContentUris.withAppendedId(CONTENT_URI, rowID);
            getContext().getContentResolver().notifyChange(_uri, null);
            return _uri;
        }

    Retrive - query()

        SQLiteQueryBuilder sqlBuilder = new SQLiteQueryBuilder();
        sqlBuilder.setTables(UserInfo.DATABASE_TABLE);
        if (uriMatcher.match(uri) == UserInfo.USERINFO_ID)
            sqlBuilder.appendWhere(UserInfo._ID + " = "+ uri.getPathSegments().get(1));
        Cursor c = sqlBuilder.query(demoDB, projection, selection,selectionArgs, null, null, sortOrder);
        c.setNotificationUri(getContext().getContentResolver(), uri);



    Update - update()
        int count = 0;
        switch (uriMatcher.match(uri)) {
        case UserInfo.USERINFO:
            count = demoDB.update(UserInfo.DATABASE_TABLE, values, selection,selectionArgs);
            break;

        case UserInfo.USERINFO_ID:
            count = demoDB.update(UserInfo.DATABASE_TABLE, values, UserInfo._ID+ " = "+ uri.getPathSegments().get(1)
                    + (!TextUtils.isEmpty(selection) ? " AND (" + selection+ ')' : ""), selectionArgs);
            break;
        default:
            throw new IllegalArgumentException("Unknown URI " + uri);
        }
        getContext().getContentResolver().notifyChange(uri, null);



  Delete - delete()   
    int count = 0;
    switch (uriMatcher.match(uri)) {
        case UserInfo.USERINFO:
            count = demoDB.delete(UserInfo.DATABASE_TABLE, selection,selectionArgs);
            break;
        case UserInfo.USERINFO_ID:
            String id = uri.getPathSegments().get(1);
            count = demoDB.delete(UserInfo.DATABASE_TABLE, UserInfo._ID+ " = "+ id+ (!TextUtils.isEmpty(selection) ? " AND (" + selection+ ')' : ""), selectionArgs);
            break;
        default:
            throw new IllegalArgumentException("Unknown URI " + uri);
        }
        getContext().getContentResolver().notifyChange(uri, null);

Create a Database Helper to Create database Schema
Refer : http://about-android.blogspot.com/2009/12/android-hello-world-activity-sample.html

Accessing Our Content Provider
    Create or Insert
        ContentValues values = new ContentValues();
        values.put(UserInfo.isactive, "Y");
        Uri uri = getContentResolver().insert(MyContentProvider.CONTENT_URI, values);

    Retrieve
        String resultStr = "";
        Uri allTitles = Uri.parse("content://"+ MyContentProvider.PROVIDER_NAME + "/"+ UserInfo.DATABASE_TABLE);

        Cursor c = managedQuery(allTitles, null, null, null, "");
        if (c.moveToFirst()) {
            do {
                resultStr = c.getString(c.getColumnIndex(UserInfo._ID))+ ", "+ c.getString(c.getColumnIndex(UserInfo.isactive));
                Toast.makeText(MainActivity.this, resultStr,Toast.LENGTH_LONG).show();
            } while (c.moveToNext());
        }