Question

I have an class that extends ExpandableListActivity. To fill the data for this list, I’m using a class that extends SimpleCursorTreeAdapter. I have a group (top-level) cursor that looks something like this:

mGroupCursor = ((MyApplication)getApplication()).
    getDatabaseHelper().getGroupCursor();
startManagingCursor(mGroupCursor);

Of course, I also need to provide the child cursors:

@Override
protected Cursor getChildCursor(Cursor groupCursor)
{
    Cursor childCursor = ((MyApplication)getApplication().
        getDatabaseHelper().
        getChildCursorForGroup(groupCursor.getInt(mGroupIdIndex));
    startManagingCursor(childCursor);
    return childCursor;
}

I was under the impression that I could call startManagingCursor on these cursors and everything would be taken care of. Apparently that is not the case, because leaving the list view and coming back with the back button throws an exception, “unable to resume activity: attempting to requery closed cursor” or something like that.

Removing the calls to startManagingCursor() fixes the problem, although I think that this is not really the right way to do things because in this case I’m not closing the cursors anywhere.

What is the recommended way to handle these cursors? I’m looking for something simple and lightweight. My database is a local SQLite database and is relatively small, so as long as the performance isn’t unreasonably slow it’s not an issue for me.

Answer 1

startManagingCursor is obsolete. I’d look at using an AsyncTask to get the cursors in the background, and set the observers yourself.