Develop Reference

How to check if accessibility service crashed (Android Pie now displays this info in settings)?

I've found out that Android 9 now shows info if accessibility service stopped working.
That was always a pain for developers who try to leverage accessibility API.
Accessibility looks like enabled, but service is stopped. And to get it back to work it is required to turn accessibility off and back on.
I would be glad if Google fixes that completely, but now they just show a hint that it's good to disable-enable it manually.
Not the best stuff, but at least something.
So, I've tried to find out how the system gets to know if the service is crashed. There happened to be a class called AccessibilityUtil and it contains hasServiceCrashed method.
Unfortunately, it checks a hidden field crashed from AccessibilityNodeInfo, which is not available for third-party developers (because of reflection denial) as well as on previous android versions.
So I'm wondering if there is an alternative way to get the info from the system which clarifies that my accessibility service is crashed/stopped working and user's action is required. Starting from Lollipop. Hints appreciated.

I came up with an idea to use a static boolean indicating the status of Accessibility Service and compare it with Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES. I've tested on multiple devices, haven't found any issue with this method.
1.Declare a static boolean in Accessibility Service.
private static boolean bServiceRunning = false;
2.In Accessibility Service, set the boolean value in onServiceConnected and onUnbind
#Override
protected void onServiceConnected() {
super.onServiceConnected();
bServiceRunning = true; //put this at the very beginning to reduce time gap
}
#Override
public boolean onUnbind(Intent intent) {
bServiceRunning = false;
return super.onUnbind(intent);
}
3.Create a static function in Accessibility Service
public static boolean bGetServiceStatus(){
return bServiceRunning;
}
With the boolean flag, I can know if the accessibility service is running in the desired state. When the service is being forced to stop, onUnbind will be called so the boolean value turns into false.
4.We use Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES to get accessibility service switch status
public static boolean bIsAccessibilityServiceEnabled(Context context, Class<?> accessibilityService) {
ComponentName expectedComponentName = new ComponentName(context, accessibilityService);
String strServicesSettingResult = Settings.Secure.getString(context.getContentResolver(), Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES);
if (strServicesSettingResult == null){
return false;
}
TextUtils.SimpleStringSplitter colonSplitter = new TextUtils.SimpleStringSplitter(':');
colonSplitter.setString(strServicesSettingResult);
while (colonSplitter.hasNext()) {
String strComponentName = colonSplitter.next();
ComponentName enabledService = ComponentName.unflattenFromString(strComponentName);
if (enabledService != null && enabledService.equals(expectedComponentName))
return true;
}
return false;
}
5.And this is what we want, we check with the above two methods the determine the real state of accessibility service.
public static int intIsAccessibilityServiceEnabled_WithCrashCheck(Context context, Class<?> accessibilityService){
//return 0 if Accessibility Service enabled and running
//return -1 if Accessibility Service disabled and not running
//return -2 if Accessibility Service enabled but stopped working or crashed
//first check Accessibility Service boolean
if(bGetServiceStatus()){
//service is running
return 0;
}else{
//service not running, now double check with Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES
boolean bResult = bIsAccessibilityServiceEnabled(context, accessibilityService);
if(!bResult){
//Accessibility Service is disabled
return -1;
}else{
//Accessibility Service is enabled, but service is not actually running, Accessibility Service is crashed
return -2;
}
}
}
Using "AccessibilityManager" also works the same, but I prefer a more "lightweight" version with static boolean for better performance.
Note: Using Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES without another doublecheck will cause a bug. The value is not synced. The result doesn't always represent the real service status. The following steps can create such a case :
Start an accessibility service then go to App settings force stop the App.
Now you can see the accessibility service switch is turned off. (Seems enough currently, but the next step will create a problem)
Start the accessibility service again,on Android 9.0+ devices you'll find out the switch is switched on, but the service is actually not running, and now it displays "Not
working. Tap for info."
2022/11/29 Edit: This bug is fixed according to this issue tracker. I can no longer reproduce this bug on my new Android 12 & 13 devices. However, devices with old Android firmware still has this bug. (The patch is also applied to the newest AVD images. To test this bug with AVD, now you must download old revisions of the AVD images.)

Android generally prevents apps from running if they crash repeatedly. This behavior for an accessibility service can obviously affect users who depend on the service, but since these services can effectively control the UI, having one that crashes repeatedly could also make the device unusable.
It hadn't occurred to me that anyone else would be interested in the crashed field in AccessibilityServiceInfo. I populated that field using data only available to the system unfortunately. I compare the list of services that are enabled with the list of those that are bound.
If you're interested if your service is prevented from running, you could probably do something similar by keeping track of when onBind and onUnbind is called and looking at the list of enabled services from AccessibilityManager.

I don't know if this is a solution. But I did find when it doesn't work: if I use "dumpsys accessibility", the services part is empty, looks like:
User state[attributes:{id=0,
currentUser=true,
touchExplorationEnabled=false,
displayMagnificationEnabled=false,
navBarMagnificationEnabled=false,
autoclickEnabled=false}
services:{}]
Maybe you can check if the services is empty.

Periodic Work manager not showing notification on android pie when not charging or screen off

I have an app that should show a notification every 2 hours and should stop if user has already acted upon the notif. Since background services are history now, I thought of using WorkManager ("android.arch.work:work-runtime:1.0.0-beta01") for the same.
My problem is that although the work manager is successfully showing the notifications when app is running, but it won't show notification consistently in the following cases(I reduced the time span from 2 hours to 2 minutes to check the consistency):
when app is killed from the background.
device is in screen off.
state device is in unplugged state(i.e not charging).
By consistency , i mean that the notifications show at least once in the given time span. for 2 minutes time span, the freq of notifications went from once every 4 minutes to completely not show any notification at all. for 2 hours timespan( the timespan that i actually want), its been 4 hours and i haven't got a single notification. Here is the Code i am using for calling WorkManger:
public class CurrentStreakActivity extends AppCompatActivity {
...
#Override
protected void onCreate(Bundle savedInstanceState) {
...
setDailyNotifier();
...
}
private void setDailyNotifier() {
Constraints.Builder constraintsBuilder = new Constraints.Builder();
constraintsBuilder.setRequiresBatteryNotLow(false);
constraintsBuilder.setRequiredNetworkType(NetworkType.NOT_REQUIRED);
constraintsBuilder.setRequiresCharging(false);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
constraintsBuilder.setRequiresDeviceIdle(false);
}
Constraints constraints =constraintsBuilder.build();
PeriodicWorkRequest.Builder builder = new PeriodicWorkRequest
.Builder(PeriodicNotifyWorker.class, 2, TimeUnit.HOURS);
builder.setConstraints(constraints);
WorkRequest request = builder.build();
WorkManager.getInstance().enqueue(request);
}
....
}
Here is the worker class(i can post showNotif(..) and setNotificationChannel(...) too if they might be erroronous):
public class PeriodicNotifyWorker extends Worker {
private static final String TAG = "PeriodicNotifyWorker";
public PeriodicNotifyWorker(#NonNull Context context, #NonNull WorkerParameters workerParams) {
super(context, workerParams);
Log.e(TAG, "PeriodicNotifyWorker: constructor called" );
}
#NonNull
#Override
public Result doWork() {
// Log.e(TAG, "doWork: called" );
SharedPreferences sp =
getApplicationContext().getSharedPreferences(Statics.SP_FILENAME, Context.MODE_PRIVATE);
String lastcheckin = sp.getString(Statics.LAST_CHECKIN_DATE_str, Statics.getToday());
// Log.e(TAG, "doWork: checking shared preferences for last checkin:"+lastcheckin );
if (Statics.compareDateStrings(lastcheckin, Statics.getToday()) == -1) {
Log.e(TAG, "doWork: last checkin is smaller than today's date, so calling creating notification" );
return createNotificationWithButtons(sp);
}
else {
Log.e(TAG, "doWork: last checkin is bigger than today's date, so no need for notif" );
return Result.success();
}
}
private Result createNotificationWithButtons(SharedPreferences sp) {
NotificationManager manager =
(NotificationManager) getApplicationContext().getSystemService((NOTIFICATION_SERVICE));
String channel_ID = "100DaysOfCode_ID";
if (manager != null) {
setNotificationChannel(manager,channel_ID);
showNotif(manager, channel_ID, sp);
return Result.success();
}
else {
return Result.failure();
}
I am using a xiaomi miA2 androidOne device with Android Pie(SDK 28). There are a few other things that are troubling me:
What can i possibly do to know if my WorkManager is running? Other that just wait for 2 hours and hope for a notification. I actually tried something like that, keeping my phone connected to pc and checking android studio's logcat every now and then. It DOES run all the logs when the worker is actually called, but i don't think that's a correct way to test it, or is it?
In the above Code, the setDailyNotifier() is called from the onCreate() every time the app is opened. Isn't it Wrong? shouldn't there be some unique id for every WorkRequest and a check function like WorkManger.isRequestRunning(request.getID) which could let us check if a worker is already on the given task??If this was a case of AsyncTask, then boy we would have a mess.
I have also checked #commonsware's answer here about wakelock when screen is off, but i remember that work manager does use alarm manager in the inside when available. So what am I missing here?

Few comments:
WorkManager has a minimum periodic interval of 15minutes and does not guarantee to execute your task at a precise time. You can read more about this on this blog.
All the usual background limitation you've on newer Android releases are still relevant when you use WorkManager to schedule your tasks. WorkManager guarantees that the task are executed even if the app is killed or the device is restated, but it cannot guarantee the exact execution.
There's one note about the tasks being rescheduled when your app is killed. Some OEM have done modification to the OS and the Launcher app that prevents WorkManager to be able to accomplish these functionality.
Here's the issuetracker discussion:
Yes, it's true even when the phone is a Chinese phone.
The only issue that we have come across is the case where some Chinese OEMs treat swipe to dismiss from Recents as a force stop. When that happens, WorkManager will reschedule all pending jobs, next time the app starts up. Given that this is a CDD violation, there is not much more that WorkManager can do given its a client library.
To add to this, if a device manufacturer has decided to modify stock Android to force-stop the app, WorkManager will stop working (as will JobScheduler, alarms, broadcast receivers, etc.). There is no way to work around this. Some device manufacturers do this, unfortunately, so in those cases WorkManager will stop working until the next time the app is launched.

As of now , i have this app installed for last 8 days and i can confirm that the code is correct and app is working fine. as said by pfmaggi , the minimum time interval for work manager to schedule the work is 15 minutes, so there is a less chance that the WorkManager would have worked as expected in my testing conditions( of 2 minutes ) . Here are some of my other observations:
Like I said in the question that i was unable to recieve a notification for 4 hours even though i have passed the repeat interval as 2 hours. This was because of Flex Time. I passed in the flex time of 15 minutes and now it shows notifications between correct time interval. so i will be marking pfmaggi's answer as correct.
The problem of repeated work request can be solved by replacing WorkManager.getInstance().enqueue(request) with WorkManager.getInstance().enqueueUniqueWork(request,..)
I was still unable to find a way to test the work manager in the way i have described.

App using Mobile Android GNSK crashes when identifyAlbumAsync() is called before audioProcessStart()

I have being upgrading an application to use the new Mobile Android GNSK but I have noticed that using the new MusicID-Stream is a little bit tricky. If the "identifyAlbumAsync" method get executed before the "audioProcessStart" method(since this need to be executed in a different thread), the application just crashes. In the Gracenote Demo application, the "audioProcessStart" method is continuously running so there is no need to synchronize its execution with the "identifyAlbumAsync" method call. Is it the way it is supposed to be used? It will be convenient if the application didn't crashed at least when the methods are not executed in order. Also in our application, we don't want to have the "audioProcessStart" method continuously like it is done in the demo application. We only want to run the "audioProcessStart" method when the user request identification and when the song playing gets identified , we want to stop the audio processing by calling "audioProcessStop". Is there an easy way to do this? Right now, we are getting the Thread where "identifyAlbumAsync" is running to sleep for 2 seconds in order to make sure that the Thread where the "audioProcessStart" method is supposed to run has time to get executed. Thank you in advance for your prompt response

In the upcoming 1.2 release, IGnMusicIdStreamEvents includes a callback that signals audio-processing has started, and an ID can be synced with this, e.g.:
#Override
public void musicIdStreamProcessingStatusEvent( GnMusicIdStreamProcessingStatus status, IGnCancellable canceller ) {
if (GnMusicIdStreamProcessingStatus.kStatusProcessingAudioStarted.compareTo(status) == 0) {
try {
gnMusicIdStream.identifyAlbumAsync();
} catch (GnException e) { }
}
}

Thanks for the feedback, you're right about this issue. Unfortunately right now sleeping is the best solution. But we are adding support for an explicit sync event in an upcoming release, please stay tuned.

Detect if an android app is running on background

I want to check if my app is running on a background mode.
The problem is that i have many activities(list activities, map activities etc.). Initially I have tried in the life cycle's resume and pause(or the onUserLeaveHint) methods to set a static boolean as true or false and work with this way. But this obviously can't work because when I move from one activity to another, the previous one get paused.
Also, I've read here on stackoverflow that the getRunningTasks() should be used only for debugging purposes. I did a huge research but I can't find a solution. All I want to do is to be able to detect if a the app is running on a background. Can anyone propose me a way, or express any thought on how can I do that?

You can try the same mechanism (a boolean attribute) but on application side rather than activity side. Create a class which extends Application, declare it in the manifest file under <application android:name=YourClassApp>.
EDIT: I assume you know that activities aren't intended for background processing, if not you should take a look at the Services.

I don't know if this will help but you can use
getApplicaton().registerActivityLifecycleCallbacks(yourClass);
To get a birds eye view of how your activities are displayed in the FG. (For older s/w you can use this)
If your Application has a Service you could have a static get/set which accesses a static variable. Do not do this in Activities though, it causes mem leaks.
But realistically speaking there is no tidy way of tracking if your application is running or not.

I had the same problemen when overwriting the Firebase push messaging default behavior (show notifications only when in the background) I checked how Firebase did this by looking in the .class file com.google.firebase.messaging.zzb:53 (firebase-messaging:19.0.1) which appears to us getRunningAppProcesses. Mind you FireBase is created by Google them self. So I'm assuming it's pretty save to use. Cleaned up version:
List<ActivityManager.RunningAppProcessInfo> runningApps;
boolean isInForeground =false;
if ((runningApps = ((ActivityManager)this.getApplication().getSystemService(Context.ACTIVITY_SERVICE)).getRunningAppProcesses()) != null) {
Iterator runningApp = runningApps.iterator();
int myPid = Process.myPid();
while(runningApp.hasNext()) {
ActivityManager.RunningAppProcessInfo processInfo;
if ((processInfo = (ActivityManager.RunningAppProcessInfo)runningApp.next()).pid == myPid) {
isInForeground = processInfo.importance == 100;
break;
}
}
}

How to detect when the user launches another app? (Android)

I'm trying to build an application where my application runs in the background and detects when the user launches another application so that I can control the flow from thereon.
To illustrate my query, I'd like to specify an example.
My application is running in the background (say as a Service), and the user has just clicked on application 'XYZ'. Is it possible for my app to detect that app 'XYZ' has been launched?
More than just detecting whether 'XYZ's Activity has come to the foreground,I want to detect whther 'XYZ' has been launched or not. Say someone launches 'Whatsapp Messenger', I want to know if my app can know that 'Whatsapp Messenger' has been launched.
EDIT : A lot of people think I'm trying to build malware, but I'm not. I'm trying to build an app for a high school project. I want a stat to see how often I use my camera as part of a psych project. :/
Thanks in advance,
Sumit.

Yes, You can find the which application is launched, by Tracking the Logcat. Just Track on ActivityManager tag with info -I log.
From adb shell Command is,
adb logcat ActivityManager:I *:S
From your application code,
logcat ActivityManager:I *:S
And in Logcat you can find a line something like,
I/ActivityManager( 585): Starting activity: Intent { action=android.intent.action...}
When any application will launched.
It is logcat output that shows that the message relates to priority level "I" and tag "ActivityManager":
Update:
Just add permission in your Application's manifest file,
android.permission.READ_LOGS

I guess you should have a look at "app protector" applications in the Google Play. They detect that user launched another application. That is done by reading system logs. Try opening LogCat and reading logs after you launched any application on device. You'll be surprised.
And where should you go from there? I guess you should try aLogCat app. It's freen and open-source. That will help you to actually read logs.
All this is considered to be a security breach in Android by some developers, though.

I have made a service which can detect if other application launches. I have made it for dialer. similarly that can be replaced by any package name.
#Override
public int onStartCommand(Intent intent, int flags, int startId){
Toast.makeText(this,"Service Started", Toast.LENGTH_LONG).show();
final String str = "";
Timer timer = new Timer();
timer.scheduleAtFixedRate(new TimerTask() {
int phonelaunched = 0,phoneclosed =0;
int phonelaunches = 1;
#Override
public void run() {
ActivityManager am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningAppProcessInfo> runningAppProcessInfo = am.getRunningAppProcesses();
for ( ActivityManager.RunningAppProcessInfo appProcess: runningAppProcessInfo ) {
Log.d(appProcess.processName.toString(),"is running");
if (appProcess.processName.equals("com.android.dialer")) {
if ( appProcess.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND /*isForeground(getApplicationContext(),runningAppProcessInfo.get(i).processName)*/){
if (phonelaunched == 0 ){
phonelaunched = 1;
Log.d(str,"dude phone has been launched");
}
else if (phoneclosed == 1){
phonelaunches++;
phoneclosed = 0;
Log.d(String.valueOf(phonelaunches),"dude that was counter");
}
}
else {
phoneclosed = 1;
Log.d(str,"dude phone has been closed");
}
}
}
}
},2000,3000);
return START_STICKY;
}
Here I go through all the running tasks and check if it is our intended application. If so I check if the application is foreground and application is never launched using 'phonelaunched' variable. phoneclosed is used when intended application is in background and variable is set accordingly.
All this is implemented in Service class

In my book, by the way you posed the question, that sounds like hi-jacking an app in a certain way for your service to control, bordering on malware jinx. But it will not work in Android - plain and simple due to the permissions of each application is different. Thereby, each app are isolated from one another. So to answer your question bluntly, its No.
As the other answer suggested - you can monitor the logcat but.. then again... why?