Why doesn't the notification URI work for a MergeCursor?

Question

Suppose you have a CONTENT_URI inside your ContentProvider in which you want to do some complex stuff and return a combination of Cursors (MergeCursor) instead of a simple, single Cursor.

It so happens that if you set the notification URI on the MergeCursor instead of a cursor from within that MergeCursor, the notification is not going to work.

Initial code:

            Cursor[] cursors = { extraCursorBefore, usersCursor, extraCursorAfter };
            Cursor extendedCursor = new MergeCursor(cursors);
            // Make sure that potential listeners are getting notified
            extendedCursor.setNotificationUri(getContext().getContentResolver(), CONTENT_URI_PEOPLE);
            return extendedCursor;

PS: If by any means, somebody has another idea, or figures out why the hell this didn't work on the original MergeCursor, then please, share your knowledge.

Answer 1

So you need to set the notification URI on a Cursor from within the resulting MergeCursor.

Code that actually works:

            Cursor[] cursors = { extraCursorBefore, usersCursor, extraCursorAfter };
            Cursor extendedCursor = new MergeCursor(cursors);
            // Make sure that potential listeners are getting notified
            usersCursor.setNotificationUri(getContext().getContentResolver(), CONTENT_URI_PEOPLE);
            return extendedCursor;