1 /* 2 * Copyright (C) 2017 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 androidx.lifecycle; 18 19 import android.app.Activity; 20 import android.app.Application; 21 import android.content.Context; 22 import android.os.Bundle; 23 24 import androidx.annotation.VisibleForTesting; 25 26 import java.util.concurrent.atomic.AtomicBoolean; 27 28 /** 29 * When initialized, it hooks into the Activity callback of the Application and observes 30 * Activities. It is responsible to hook in child-fragments to activities and fragments to report 31 * their lifecycle events. Another responsibility of this class is to mark as stopped all lifecycle 32 * providers related to an activity as soon it is not safe to run a fragment transaction in this 33 * activity. 34 */ 35 class LifecycleDispatcher { 36 37 private static AtomicBoolean sInitialized = new AtomicBoolean(false); 38 39 static void init(Context context) { 40 if (sInitialized.getAndSet(true)) { 41 return; 42 } 43 ((Application) context.getApplicationContext()) 44 .registerActivityLifecycleCallbacks(new DispatcherActivityCallback()); 45 } 46 47 @SuppressWarnings("WeakerAccess") 48 @VisibleForTesting 49 static class DispatcherActivityCallback extends EmptyActivityLifecycleCallbacks { 50 51 @Override 52 public void onActivityCreated(Activity activity, Bundle savedInstanceState) { 53 ReportFragment.injectIfNeededIn(activity); 54 } 55 56 @Override 57 public void onActivityStopped(Activity activity) { 58 } 59 60 @Override 61 public void onActivitySaveInstanceState(Activity activity, Bundle outState) { 62 } 63 } 64 65 private LifecycleDispatcher() { 66 } 67 } 68
