1 /*
2  * Copyright (C) 2020 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.Context;
20 import android.content.Intent;
21 import android.content.pm.PackageManager;
22 import android.content.pm.ResolveInfo;
23 
24 import java.util.List;
25 
26 /**
27  * An observer / callback to create and register by
28  * {@link ActivityManager#registerHomeVisibilityObserver} so that it's triggered when
29  * visibility of home page changes.
30  * TODO: b/144351078 expose as SystemApi
31  * @hide
32  */
33 public abstract class HomeVisibilityObserver {
34     private Context mContext;
35     private ActivityManager mActivityManager;
36     /** @hide */
37     IProcessObserver.Stub mObserver;
38     /** @hide */
39     boolean mIsHomeActivityVisible;
40 
41     /** @hide */
init(Context context, ActivityManager activityManager)42     void init(Context context, ActivityManager activityManager) {
43         mContext = context;
44         mActivityManager = activityManager;
45         mIsHomeActivityVisible = isHomeActivityVisible();
46     }
47 
48     /**
49      * The API that needs implemented and will be triggered when activity on home page changes.
50      */
onHomeVisibilityChanged(boolean isHomeActivityVisible)51     public abstract void onHomeVisibilityChanged(boolean isHomeActivityVisible);
52 
HomeVisibilityObserver()53     public HomeVisibilityObserver() {
54         mObserver = new IProcessObserver.Stub() {
55             @Override
56             public void onForegroundActivitiesChanged(int pid, int uid, boolean fg) {
57                 boolean isHomeActivityVisible = isHomeActivityVisible();
58                 if (mIsHomeActivityVisible != isHomeActivityVisible) {
59                     mIsHomeActivityVisible = isHomeActivityVisible;
60                     onHomeVisibilityChanged(mIsHomeActivityVisible);
61                 }
62             }
63 
64             @Override
65             public void onForegroundServicesChanged(int pid, int uid, int fgServiceTypes) {
66             }
67 
68             @Override
69             public void onProcessDied(int pid, int uid) {
70             }
71         };
72     }
73 
isHomeActivityVisible()74     private boolean isHomeActivityVisible() {
75         List<ActivityManager.RunningTaskInfo> tasks = mActivityManager.getRunningTasks(1);
76         if (tasks == null || tasks.isEmpty()) {
77             return false;
78         }
79 
80         String top = tasks.get(0).topActivity.getPackageName();
81         if (top == null) {
82             return false;
83         }
84 
85         // We can assume that the screen is idle if the home application is in the foreground.
86         final Intent intent = new Intent(Intent.ACTION_MAIN, null);
87         intent.addCategory(Intent.CATEGORY_HOME);
88 
89         ResolveInfo info = mContext.getPackageManager().resolveActivity(intent,
90                 PackageManager.MATCH_DEFAULT_ONLY);
91         if (info != null && top.equals(info.activityInfo.packageName)) {
92             return true;
93         }
94 
95         return false;
96     }
97 }
98