| /* |
| * Copyright (C) 2012 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License |
| */ |
| |
| package com.android.contacts.database; |
| |
| import android.content.AsyncQueryHandler; |
| import android.content.ContentResolver; |
| import android.database.Cursor; |
| import android.net.Uri; |
| |
| /** |
| * An {@AsyncQueryHandler} that will never return a null cursor. |
| * <p> |
| * Instead, will return a {@link Cursor} with 0 records. |
| */ |
| public abstract class NoNullCursorAsyncQueryHandler extends AsyncQueryHandler { |
| |
| public NoNullCursorAsyncQueryHandler(ContentResolver cr) { |
| super(cr); |
| } |
| |
| @Override |
| public void startQuery(int token, Object cookie, Uri uri, String[] projection, String selection, |
| String[] selectionArgs, String orderBy) { |
| final CookieWithProjection projectionCookie = new CookieWithProjection(cookie, projection); |
| super.startQuery(token, projectionCookie, uri, projection, selection, selectionArgs, |
| orderBy); |
| } |
| |
| @Override |
| protected final void onQueryComplete(int token, Object cookie, Cursor cursor) { |
| CookieWithProjection projectionCookie = (CookieWithProjection) cookie; |
| |
| super.onQueryComplete(token, projectionCookie.originalCookie, cursor); |
| |
| if (cursor == null) { |
| cursor = new EmptyCursor(projectionCookie.projection); |
| } |
| onNotNullableQueryComplete(token, projectionCookie.originalCookie, cursor); |
| } |
| |
| protected abstract void onNotNullableQueryComplete(int token, Object cookie, Cursor cursor); |
| |
| /** |
| * Class to add projection to an existing cookie. |
| */ |
| private static class CookieWithProjection { |
| public final Object originalCookie; |
| public final String[] projection; |
| |
| public CookieWithProjection(Object cookie, String[] projection) { |
| this.originalCookie = cookie; |
| this.projection = projection; |
| } |
| } |
| } |