WidgetDAO.java revision ff62e7fa903e3b6b11d0443543725c1351ab289d 
1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.deskclock.data;
18
19import android.content.SharedPreferences;
20
21/**
22 * This class encapsulates the transfer of data between widget objects and their permanent storage
23 * in {@link SharedPreferences}.
24 */
25final class WidgetDAO {
26
27    /** Suffix for a key to a preference that stores the instance count for a given widget type. */
28    private static final String WIDGET_COUNT = "_widget_count";
29
30    private WidgetDAO() {}
31
32    /**
33     * @param widgetProviderClass indicates the type of widget being counted
34     * @param count the number of widgets of the given type
35     * @return the delta between the new count and the old count
36     */
37    static int updateWidgetCount(SharedPreferences prefs, Class widgetProviderClass, int count) {
38        final String key = widgetProviderClass.getSimpleName() + WIDGET_COUNT;
39        final int oldCount = prefs.getInt(key, 0);
40        if (count == 0) {
41            prefs.edit().remove(key).apply();
42        } else {
43            prefs.edit().putInt(key, count).apply();
44        }
45        return count - oldCount;
46    }
47}