1/*
2 * Copyright (C) 2006 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 android.content;
18
19import android.content.res.Configuration;
20
21/**
22 * The set of callback APIs that are common to all application components
23 * ({@link android.app.Activity}, {@link android.app.Service},
24 * {@link ContentProvider}, and {@link android.app.Application}).
25 */
26public interface ComponentCallbacks {
27    /**
28     * Called by the system when the device configuration changes while your
29     * component is running.  Note that, unlike activities, other components
30     * are never restarted when a configuration changes: they must always deal
31     * with the results of the change, such as by re-retrieving resources.
32     *
33     * <p>At the time that this function has been called, your Resources
34     * object will have been updated to return resource values matching the
35     * new configuration.
36     *
37     * @param newConfig The new device configuration.
38     */
39    void onConfigurationChanged(Configuration newConfig);
40
41    /**
42     * This is called when the overall system is running low on memory, and
43     * would like actively running process to try to tighten their belt.  While
44     * the exact point at which this will be called is not defined, generally
45     * it will happen around the time all background process have been killed,
46     * that is before reaching the point of killing processes hosting
47     * service and foreground UI that we would like to avoid killing.
48     *
49     * <p>Applications that want to be nice can implement this method to release
50     * any caches or other unnecessary resources they may be holding on to.
51     * The system will perform a gc for you after returning from this method.
52     */
53    void onLowMemory();
54}
55