ListView filtering with CursorLoader AND FilterQueryProvider?

In our Project we deal a lot with Lists and used it in the past with the following "pattern":

ListView is in a Fragment, gets initialized in onActivityCreated where we first start CursorLoaders and then in onFinish swapCusor to the ListAdapter. We then implemented a search functionality using the filterQueryProvider which just returns a cursor with contentResolver.query(...). If i have done some orientation changes while something in the list was selected i got the following error in many cases (not regularly):

android.database.StaleDataException: Attempted to access a cursor after it has been closed.
12-05 10:36:59.531: E/ACRA(12079):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1967)
12-05 10:36:59.531: E/ACRA(12079):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1992)
12-05 10:36:59.531: E/ACRA(12079):  at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3378)
12-05 10:36:59.531: E/ACRA(12079):  at android.app.ActivityThread.access$700(ActivityThread.java:127)
12-05 10:36:59.531: E/ACRA(12079):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1162)
12-05 10:36:59.531: E/ACRA(12079):  at android.os.Handler.dispatchMessage(Handler.java:99)
12-05 10:36:59.531: E/ACRA(12079):  at android.os.Looper.loop(Looper.java:137)
12-05 10:36:59.531: E/ACRA(12079):  at android.app.ActivityThread.main(ActivityThread.java:4448)
12-05 10:36:59.531: E/ACRA(12079):  at java.lang.reflect.Method.invokeNative(Native Method)
12-05 10:36:59.531: E/ACRA(12079):  at java.lang.reflect.Method.invoke(Method.java:511)
12-05 10:36:59.531: E/ACRA(12079):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:823)
12-05 10:36:59.531: E/ACRA(12079):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:590)
12-05 10:36:59.531: E/ACRA(12079):  at dalvik.system.NativeStart.main(Native Method)
12-05 10:36:59.531: E/ACRA(12079): Caused by: android.database.StaleDataException: Attempted to access a cursor after it has been closed.
12-05 10:36:59.531: E/ACRA(12079):  at android.database.BulkCursorToCursorAdaptor.throwIfCursorIsClosed(BulkCursorToCursorAdaptor.java:75)
12-05 10:36:59.531: E/ACRA(12079):  at android.database.BulkCursorToCursorAdaptor.getColumnNames(BulkCursorToCursorAdaptor.java:170)
12-05 10:36:59.531: E/ACRA(12079):  at android.database.AbstractCursor.getColumnIndex(AbstractCursor.java:248)
12-05 10:36:59.531: E/ACRA(12079):  at android.database.AbstractCursor.getColumnIndexOrThrow(AbstractCursor.java:266)
12-05 10:36:59.531: E/ACRA(12079):  at android.database.CursorWrapper.getColumnIndexOrThrow(CursorWrapper.java:78)
12-05 10:36:59.531: E/ACRA(12079):  at android.support.v4.widget.CursorAdapter.swapCursor(CursorAdapter.java:344)
12-05 10:36:59.531: E/ACRA(12079):  at

this is case when using swapCursor in onLoadFinished after the orientation Change.

I now reimplemented the filter functionality using restartLoader with arguments and using the Contacts.CONTENT_FILTER_URI with appended path which is the constraint and then swapping this cursor in onLoadFinished, so i removed the filterQueryProvider, which looks to work fine.

The question is: Is there a possibility (or good practise) to use CursorLoader initially AND the filterQueryProvider? or do i have to decide? because the same result i reach when just using the filterQueryProvider and just do the filtering with constraint null which just loads my required contactlist and does the filtering afterwards.

Any recommendations? I did not found mathinc information on this via google ;)

this is my current LoaderCallbacks implementation btw:

 private LoaderManager.LoaderCallbacks<Cursor> phoneBookContactsLoaderCallback = new LoaderManager.LoaderCallbacks<Cursor>() {

        @Override
        public Loader<Cursor> onCreateLoader(int id, Bundle args) {
            // if(constraint != null && constraint.length() > 0) {
            // selection = Contacts.DISPLAY_NAME + " LIKE ?";
            // selectionArgs = new String [] {"%" + constraint + "%"};
            // }
            numLoaderManagersRunning++;
            String constraint = null;
            if(args != null){
                constraint = args.getString(CONSTRAINT);
            }

            Uri uri = null;

            if(constraint!= null && !constraint.isEmpty()){
                uri =  Uri.withAppendedPath(Contacts.CONTENT_FILTER_URI, constraint);
            } else {
                uri = Contacts.CONTENT_URI;
            }


            return new CursorLoader(getActivity(), uri , PROJECTION_PHONEBOOK_CONTACTS,
                    null, null, Contacts.DISPLAY_NAME + " COLLATE NOCASE ASC");
        }

        @Override
        public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
            Logger.e(TAG, "Load finished ");
            // phoneBookContactsCursorAdapter.swapCursor(new MatrixCursor(new String [] { Contacts._ID,
            // Contacts.DISPLAY_NAME, Contacts.PHOTO_ID }));
            phoneBookContactsCursorAdapter.swapCursor(data);
            if (actualMultiFilterListener != null){
                actualMultiFilterListener.onFilterComplete(data.getCount());
            }
//filterList("");
            numLoaderManagersRunning--;

            if (numLoaderManagersRunning <= 0) {
                // The list should now be shown.
                if (isResumed()) {
                    setListShown(true);
                } else {
                    setListShownNoAnimation(true);
                }
            }
        }

        @Override
        public void onLoaderReset(Loader<Cursor> loader) {
//            phoneBookContactsCursorAdapter.swapCursor(null);
            Logger.e(TAG, "Load resetted ");
        }
    };

A little bit late but I have faced exact same problem and comments were not well explanatory. For those who faces the problem here is the solution:

"Stop using FilterQueryProvider. CursorLoader is also a replacement for that: restart it with your filter and you'll be fine." (source)

Which means;

instead of doing this:

@Override
public Cursor runQuery(CharSequence listId) {
    return mDb.getContacts(listId);  
}// DO NOT set direct database query, has no observation at all.

@Override
public Cursor runQuery(CharSequence listId) {
    return getContentManager.query(....,new String[]{listId}...
}// DO NOT return content manager result, forgets observers.

@Override
public Cursor runQuery(CharSequence listId) {
    Bundle bundle = new Bundle();
    bundle.putCharSequence("selected", listId);
    getLoaderManager().restartLoader(CURSOR_LOADER_CONTACTS, bundle, MainActivity.this);
    return null;
}// DO NOT restart the cursor loader with new info, screws observers.

with combination of mContactAdapter.getFilter().filter(id+""); (while applying filter)

do this:

@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
    switch (id) {
        case CURSOR_LOADER_CONTACTS:
            long mListId = 0;
            if (args != null) {
                mListId = args.getLong(CONTACT_FILTER);
            }
            return new CursorLoader(this, ContentProvider.CONTACT_DISPLAY_URI, null, ContactTable.COLUMN_GROUP_ID+"=?", new String[]{id+""}, null); 
    } //Apply filter here with new info comes from 'restartLoader'
    return null;
}

with combination of getLoaderManager().restartLoader(MainActivity.CURSOR_LOADER_CONTACTS, bundle, MainActivity.this);

assuming MainActivity.this implements LoaderManager.LoaderCallbacks<Cursor>

when using FilterQueryProvider use restartLoader instead of initLoader

来源：https://stackoverflow.com/questions/20399284/listview-filtering-with-cursorloader-and-filterqueryprovider

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