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 17 package android.content; 18 19 import 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 * 26 * <p class="note"><strong>Note:</strong> You should also implement the {@link 27 * ComponentCallbacks2} interface, which provides the {@link 28 * ComponentCallbacks2#onTrimMemory} callback to help your app manage its memory usage more 29 * effectively.</p> 30 */ 31 public interface ComponentCallbacks { 32 /** 33 * Called by the system when the device configuration changes while your 34 * component is running. Note that, unlike activities, other components 35 * are never restarted when a configuration changes: they must always deal 36 * with the results of the change, such as by re-retrieving resources. 37 * 38 * <p>At the time that this function has been called, your Resources 39 * object will have been updated to return resource values matching the 40 * new configuration. 41 * 42 * <p>For more information, read <a href="{@docRoot}guide/topics/resources/runtime-changes.html" 43 * >Handling Runtime Changes</a>. 44 * 45 * @param newConfig The new device configuration. 46 */ 47 void onConfigurationChanged(Configuration newConfig); 48 49 /** 50 * This is called when the overall system is running low on memory, and 51 * actively running processes should trim their memory usage. While 52 * the exact point at which this will be called is not defined, generally 53 * it will happen when all background process have been killed. 54 * That is, before reaching the point of killing processes hosting 55 * service and foreground UI that we would like to avoid killing. 56 * 57 * <p>You should implement this method to release 58 * any caches or other unnecessary resources you may be holding on to. 59 * The system will perform a garbage collection for you after returning from this method. 60 * <p>Preferably, you should implement {@link ComponentCallbacks2#onTrimMemory} from 61 * {@link ComponentCallbacks2} to incrementally unload your resources based on various 62 * levels of memory demands. That API is available for API level 14 and higher, so you should 63 * only use this {@link #onLowMemory} method as a fallback for older versions, which can be 64 * treated the same as {@link ComponentCallbacks2#onTrimMemory} with the {@link 65 * ComponentCallbacks2#TRIM_MEMORY_COMPLETE} level.</p> 66 */ 67 void onLowMemory(); 68 } 69
