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.app; 18 19 import android.content.ComponentCallbacks; 20 import android.content.Context; 21 import android.content.ContextWrapper; 22 import android.content.res.Configuration; 23 24 /** 25 * Base class for those who need to maintain global application state. You can 26 * provide your own implementation by specifying its name in your 27 * AndroidManifest.xml's <application> tag, which will cause that class 28 * to be instantiated for you when the process for your application/package is 29 * created. 30 * 31 * <p class="note">There is normally no need to subclass Application. In 32 * most situation, static singletons can provide the same functionality in a 33 * more modular way. If your singleton needs a global context (for example 34 * to register broadcast receivers), the function to retrieve it can be 35 * given a {@link android.content.Context} which internally uses 36 * {@link android.content.Context#getApplicationContext() Context.getApplicationContext()} 37 * when first constructing the singleton.</p> 38 */ 39 public class Application extends ContextWrapper implements ComponentCallbacks { 40 Application()41 public Application() { 42 super(null); 43 } 44 45 /** 46 * Called when the application is starting, before any other application 47 * objects have been created. Implementations should be as quick as 48 * possible (for example using lazy initialization of state) since the time 49 * spent in this function directly impacts the performance of starting the 50 * first activity, service, or receiver in a process. 51 * If you override this method, be sure to call super.onCreate(). 52 */ onCreate()53 public void onCreate() { 54 } 55 56 /** 57 * This method is for use in emulated process environments. It will 58 * never be called on a production Android device, where processes are 59 * removed by simply killing them; no user code (including this callback) 60 * is executed when doing so. 61 */ onTerminate()62 public void onTerminate() { 63 } 64 onConfigurationChanged(Configuration newConfig)65 public void onConfigurationChanged(Configuration newConfig) { 66 } 67 onLowMemory()68 public void onLowMemory() { 69 } 70 71 // ------------------ Internal API ------------------ 72 73 /** 74 * @hide 75 */ attach(Context context)76 /* package */ final void attach(Context context) { 77 attachBaseContext(context); 78 } 79 80 } 81