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      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 public 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