Using CursorLoader to get emails causes duplication of emails

Question

I am trying to get email ids of uses contacts. For that I am using Cursor Loader. There is one problem I am getting duplicate email ids also. How to remove email duplicacy. Shou

Answer 1

If you are worried about performance and don't want to play around with cursor again in onLoadFinished(), then there is a small hack

I combined following two solutions from SO.

1. select distinct value in android sqlite

2. CursorLoader with rawQuery

And here is my working solution:

    @Override
    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
    String tableName;

    /*
     * Choose the table to query and a sort order based on the code returned
     * for the incoming URI.
     */
    switch (uriMatcher.match(uri)) {
        case NOTIFICATION:
            tableName = NOTIFICATIONS_TABLE_NAME;

            break;

        case NOTIFICATION_TIMESTAMP:

            Cursor cursor = db.query(true, NOTIFICATIONS_TABLE_NAME, projection, selection, selectionArgs, TIMESTAMP, null, sortOrder, null);
            cursor.setNotificationUri(getContext().getContentResolver(), uri);

            return cursor;

        case DOWNLOAD:
            tableName = DOWNLOADS_TABLE;
            break;
        default:
            throw new IllegalArgumentException("Unknown URI " + uri);
    }


    if (selection != null) {
        selection = selection + "=?";
    }

    Cursor cursor = db.query(tableName, projection, selection, selectionArgs, null, null, sortOrder);


    // Tell the cursor what uri to watch, so it knows when its source data
    // changes
    cursor.setNotificationUri(getContext().getContentResolver(), uri);
    return cursor;
}

If you see in this case Table name is same is first 2 cases but i created a dummy Uri to achieve this. May not be a very good approach but works perfectly.