Proper implementation of changing ListView data wi

2019-05-04 09:46发布

问题:

I have a ListView populated via a CursorAdapter. I give my user the ability to alter the data in the list. For example, the user can mark a row as being unread (the data are messages).

Suppose my user marked a row unread. Would a proper implementation mark the row in the database as read and then requery the Cursor?

回答1:

Would a proper implementation mark the row in the database as read and then requery the Cursor?

Yes, that's the right answer. The requery() will trigger an automatic update of your CursorAdapter, which will trigger an automatic update of the ListView, which will trigger an automatic smile from the user. :-)

UPDATE

The requery() method is deprecated. A better approach nowadays is to run a query to get a fresh Cursor, then use changeCursor() or swapCursor() on your CursorAdapter.



回答2:

If the cursor is back by a ContentProvider and the ContentProvider issues correct notifications, the CursorAdapter will automatically refresh itself i.e. without the need to issue an explicit requery().