Develop Reference

keeping a service running after shutting down the app

i'm trying to create an app that communicates with my localhost and search in a database.
I already make the connection and find the data, but i need to stay connected and send a notification if there's any changes in the table, but I can't figure it out how to keep the connection even when I close the app, because it closes everything, even the service.
The service doesn't stay open.
This is my Class:
public class SensorService extends Service {
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public void onCreate() {
super.onCreate();
Toast.makeText(this,"Starting",Toast.LENGTH_SHORT).show();
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
boolean bandera = true;
Toast.makeText(this, "Checking data...", Toast.LENGTH_SHORT).show();
return START_STICKY;
}
#Override
public void onTaskRemoved(Intent rootIntent) {
super.onTaskRemoved(rootIntent);
stopService(new Intent(this,SensorService.class));
startService(new Intent(this,SensorService.class));
}
#Override
public void onDestroy() {
startService(new Intent(this,SensorService.class));
}
}
Every time I close the app, the service execute one more time and no more.

If you want the service to continue running after the app is closed, you need to call the startForeground(int, Notification) method from within the service. Android limits you to running longer running services in the background only as long as a notification is displayed to the user letting them know that a service is running (like a music player or a downloading service).
This is an intentional design constraint to ensure developers do not start services in the background that run indefinitely without the user being aware. Supply your own notification (can be anything) and you should be able to run the service in the background.
For more detailed information on this method, read it at: startForeground(int, Notification)

You can use onTaskRemoved and restart the service if needed.
#Override
public void onTaskRemoved(Intent rootIntent){
super.onTaskRemoved(rootIntent);
//restart your service
}
Please note that if you use onTaskRemoved, start your service as not sticky so it won't be restarted.
#Override
public int onStartCommand(Intent intent, int flags, int startId)
{
return START_NOT_STICKY;
}

calling stopForeground leads to restart the current service

I started a foreground service with a notification id however when i try to call stopForeground(false) the service is getting restarted. But according to the android docs calling this method does not stop the service.
#Override
public void onCreate() {
LogHelper.d(TAG, "onCreate");
super.onCreate();
initMediaSeesion();
}
#Override
public int onStartCommand(Intent startIntent, int flags, int startId) {
LogHelper.d(TAG, "onStartCommand");
MediaButtonReceiver.handleIntent(mSession, startIntent);
return START_STICKY;
}
public void startNotification() {
if (!mStarted) {
Notification notification = createNotification();
if (notification != null) {
mService.startForeground(NOTIFICATION_ID, notification);
mStarted = true;
}
}
}
#Override
public void pause() {
LogHelper.d(TAG, "Calling stopForeground false");
giveUpAudioFocus();
mService.stopForeground(false);
}
Logs:
03-25 08:50:40.200 19564-19564/? D/MusicService: Calling stopForeground false
03-25 08:50:40.352 19564-19564/? D/MusicService: onCreate
03-25 08:50:40.475 19564-19564/? D/MusicService: onStartCommand
03-25 08:50:40.476 19564-19564/? D/MusicService: onStartCommand

Because you set START_STICKY when you stop the service it automatically restart.
This is what Android DOC says
For started services, there are two additional major modes of operation they can decide to run in, depending on the value they return from onStartCommand(): START_STICKY is used for services that are explicitly started and stopped as needed, while START_NOT_STICKY or START_REDELIVER_INTENT are used for services that should only remain running while processing any commands sent to them. See the linked documentation for more detail on the semantics.
Try using stopSelf();

Restart Android Started Service after application was killed

I'm trying to do a StartedService in android to send periodically the user location to a server.
Until this moment I managed to create the service and starting it from the 'parent ' application and I don't know how to keep it alive after the application was killed. From what I found on internet the 'StartCommandResult.Sticky' should restart the service if this one is killed but from some reason this is not restarted.
I overried the OnStartCommand:
public override StartCommandResult OnStartCommand(Intent intent, StartCommandFlags flags, int startId)
{
locationTask = new Task(() =>
{
//stuff to do
});
locationTask.Start();
return StartCommandResult.Sticky;
}
And the service is started like this:
Intent intent = new Intent(this.Activity, Class.FromType(typeof(LocationService)));
this.Activity.StartService(intent);
Any suggestions what should I do in order to keep my service alive after the application was killed?
As observation I'm using xamarin to do it, but I won't mind an answer in android(java).

As stated in the official documentation:
A service is "started" when an application component (such as an
activity) starts it by calling startService(). Once started, a service
can run in the background indefinitely, even if the component that
started it is destroyed. Usually, a started service performs a
single operation and does not return a result to the caller. For
example, it might download or upload a file over the network. When the
operation is done, the service should stop itself.
So, starting the service like this
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
return Service.START_STICKY;
}
Will have your service running even while your app is destroyed.
Regarding Service.START_STICKY in the official documentation:
If the system kills the service after onStartCommand() returns,
recreate the service and call onStartCommand(), but do not redeliver
the last intent. Instead, the system calls onStartCommand() with a
null intent, unless there were pending intents to start the service,
in which case, those intents are delivered. This is suitable for media
players (or similar services) that are not executing commands, but
running indefinitely and waiting for a job.

This is how I do it but its in JAVA code.
in your service you should implement a LocalBinder, onStartCommand and onCreate methods.
public class LocalBinder extends Binder {
ServiceName getService() {
return ServiceName .this;
}
}
#Override
public void onCreate() {
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.i("LocalService", "Received start id " + startId + ": " + intent);
return START_STICKY;
}
The onStartCommand should return START_STICKY;. And also, include this code on your Service:
#Override
public void onTaskRemoved(Intent rootIntent) {
// TODO Auto-generated method stub
Intent restartService = new Intent(getApplicationContext(),this.getClass());
restartService.setPackage(getPackageName());
PendingIntent restartServicePI = PendingIntent.getService(getApplicationContext(), 1, restartService, PendingIntent.FLAG_ONE_SHOT);
AlarmManager alarmService = (AlarmManager)getApplicationContext().getSystemService(Context.ALARM_SERVICE);
alarmService.set(AlarmManager.ELAPSED_REALTIME, SystemClock.elapsedRealtime() +1000, restartServicePI);
}
This will restart your Service on 1 second from the time you close it. Also, dont forget to add your service in your AndroidManifest.xml
<service android:name=".ServiceName"
android:exported="false"
android:stopWithTask="false" >
</service>

Override onStartCommand like this
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
return Service.START_STICKY;
}

For me, everything in the code was right but the problem was with the use of debugging while checking if the service was on. When I use a release version (or just dev version without connecting to the debug), the process is not killed and the service is running normally.
No idea why though. I am using Xamarin Studio 6.0.

How can we prevent a Service from being killed by OS?

I am using Service in my application and it needs to run until my application is uninstalled, but the problem is it gets killed by OS.
How can we prevent it from being killed by OS? Or if it gets killed can we restart that service again through programmatically?

You may run the service in the foreground using startForeground().
A foreground service is a service that's considered to be something
the user is actively aware of and thus not a candidate for the system
to kill when low on memory.
But bear in mind that a foreground service must provide a notification for the status bar (read here), and that the notification cannot be dismissed unless the service is either stopped or removed from the foreground.
Note: This still does not absolutely guarantee that the service won't be killed under extremely low memory conditions. It only makes it less likely to be killed.

I've been puzzled by the same issue to yours recently.but now,I've found a good solution.
First of all,you should know that, even your service was killed by OS, the onCreate method of your service would be invoked by OS in a short while.So you can do someting with the onCreate method like this:
#Override
public void onCreate() {
Log.d(LOGTAG, "NotificationService.onCreate()...");
//start this service from another class
ServiceManager.startService();
}
#Override
public void onStart(Intent intent, int startId) {
Log.d(LOGTAG, "onStart()...");
//some code of your service starting,such as establish a connection,create a TimerTask or something else
}
the content of "ServiceManager.startService()" is:
public static void startService() {
Log.i(LOGTAG, "ServiceManager.startSerivce()...");
Intent intent = new Intent(NotificationService.class.getName());
context.startService(intent);
}
However, this solution is just available for the situation of your service being killed by GC.Sometimes our service might be killed by user with Programme Manager.In this situation,your prosses will be killed,and your service will never been re-instantiated.So your service can not be restarted.
But the good news is,when the PM kill your service,it will call your onDestroy method.So we can do something with that method.
#Override
public void onDestroy() {
Intent in = new Intent();
in.setAction("YouWillNeverKillMe");
sendBroadcast(in);
Log.d(LOGTAG, "onDestroy()...");
}
The string of "YouWillNeverKillMe" is a custom action.
The most important thing of this method is,don't add any code before send the broadcast.As system will not wait for completion of onDestroy(),you must send out the broadcast as soon as posible.
Then regist a receiver in manifast.xml:
<receiver android:name=".app.ServiceDestroyReceiver" >
<intent-filter>
<action android:name="YouWillNeverKillMe" >
</action>
</intent-filter>
</receiver>
Finally,create a BroadcastReceiver,and start your service in the onReceive method:
#Override
public void onReceive(Context context, Intent intent) {
Log.d(LOGTAG, "ServeiceDestroy onReceive...");
Log.d(LOGTAG, "action:" + intent.getAction());
Log.d(LOGTAG, "ServeiceDestroy auto start service...");
ServiceManager.startService();
}
Hope this will be helpful to you,and excuse my poor written english.

Override method onStartCommand() in your service class and simply return START_STICKY (as suggested by "Its not blank"). That's all you need. If the process that runs your service gets killed (by a low memory condition for example), the Android system will restart it automatically (usually with some delay, like 5 seconds).
Don't use onStart() anymore as suggested in another answer, it's deprecated.

use
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
//**Your code **
// We want this service to continue running until it is explicitly
// stopped, so return sticky.
return START_STICKY;
}
ref Documentation lifecycle of Service.
Edit added method.

As far i know, onDestroy() will be called only when the service is explicitly stopped(Force Stop). But this method won't get called in case the service gets killed by OS/swiping the Recent Apps list. In those cases another event handler named onTaskRemoved(Intent) gets called. This is due to a defect in Android 4.3-4.4 as per the link here. Try using the below code:-
public void onTaskRemoved(Intent intent){
super.onTaskRemoved(intent);
Intent intent=new Intent(this,this.getClass());
startService(intent);
}

I found another solution of the problem which gurantees that your service will be always alive. In my case, this scheme resloves also the problem with FileObserver, which stops work after some period of time.
Use an activity (StartServicesActivity) to start the service (FileObserverService) as Foreground service.
Use BroadcastReceiver class (in example CommonReceiver) to restart your service in some special situations and in case it was killed.
I used this code in my app "Email Pictures Automatically"
https://play.google.com/store/apps/details?id=com.alexpap.EmailPicturesFree
Here is CommonReceiver class.
public class CommonReceiver extends BroadcastReceiver {
public void onReceive(Context paramContext, Intent paramIntent)
{
paramContext.startService(new Intent(paramContext, FileObserverService.class));
}
}
Here is its definition in AndroidManifest.xml just before application closing tag.
<receiver android:name="com.alexpap.services.CommonReceiver">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED"/>
</intent-filter>
<intent-filter>
<action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>
</intent-filter>
<intent-filter>
<action android:name="android.intent.action.USER_PRESENT"/>
</intent-filter>
</receiver>
Start service in StartServicesActivity activity.
Intent iFileObserver = new Intent(StartServicesActivity.this, FileObserverService.class);
StartServicesActivity.this.startService(iFileObserver);
Here is onStartCommand() method of the service.
public int onStartCommand(Intent intent, int flags, int startId) {
int res = super.onStartCommand(intent, flags, startId);
/*** Put your code here ***/
startServiceForeground(intent, flags, startId);
return Service.START_STICKY;
}
public int startServiceForeground(Intent intent, int flags, int startId) {
Intent notificationIntent = new Intent(this, StartServicesActivity.class);
notificationIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0);
Notification notification = new NotificationCompat.Builder(this)
.setContentTitle("File Observer Service")
.setContentIntent(pendingIntent)
.setOngoing(true)
.build();
startForeground(300, notification);
return START_STICKY;
}
I tested this code using Task Killer app, and each time the service was killed, it was restarted again almost immediately (performs onStartCommand()). It is restarted also each time you turn on the phone and after rebooting.
I use this code in my application, which emails every picture you take with your phone to predefinde list of emails. The sending email and list of receiving emails are set in another activity and are stored in Shared Preferences. I took about 100 pictures in several hours and all they were sent properly to receiving emails.

#Override
public void onDestroy() {
super.onDestroy();
startService(new Intent(this, YourService.class));
}
write above code in your service and your service will never stop even user want to destroy it or they want to kill it it will never kill untill your app not get uninstall from your device

You can try to start your service repeatedly, for example every 5 sec.
This way, when your service is running, it will perform onStartCommand() every 5 sec. I tested this scheme and it is very reliable, but unfortunately it increases slightly phone overhead.
Here is the code in your activity where you start the service.
Intent iFileObserver = new Intent(StartServicesActivity.this, FileObserverService.class);
PendingIntent pendingIntentFileObserver = PendingIntent.getService(StartServicesActivity.this, 0, iFileObserver, 0);
AlarmManager alarmManager = (AlarmManager)getSystemService(ALARM_SERVICE);
Date now = new Date();
//start every 5 seconds
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, now.getTime(), 5*1000, pendingIntentFileObserver);
And here is onStartCommand() of the service.
//class variable
public static boolean isStarted = false;
public int onStartCommand(Intent intent, int flags, int startId) {
int res = super.onStartCommand(intent, flags, startId);
//check if your service is already started
if (isStarted){ //yes - do nothing
return Service.START_STICKY;
} else { //no
isStarted = true;
}
/**** the rest of your code ***/
return Service.START_STICKY;
}

First create service in another process, and write broadcaster which runs in recursion in time intervals
protected CountDownTimer rebootService = new CountDownTimer(9000, 9000) {
#Override
public void onTick(long millisUntilFinished) {
}
#Override
public void onFinish() {
sendBroadcast(reboot);
this.start();
Log.d(TAG, "rebootService sending PREVENT AUTOREBOT broadcast");
}
};
After that register broadcast receiver in main process also with timer recursion that is launched after first broadcast from service arrived
protected static class ServiceAutoRebooter extends BroadcastReceiver {
private static ServiceAutoRebooter instance = null;
private RebootTimer rebootTimer = null;
private static ServiceAutoRebooter getInstance() {
if (instance == null) {
instance = new ServiceAutoRebooter();
}
return instance;
}
public class RebootTimer extends CountDownTimer {
private Context _context;
private Intent _service;
public RebootTimer(long millisInFuture, long countDownInterval) {
super(millisInFuture, countDownInterval);
}
#Override
public void onTick(long millisUntilFinished) {
}
#Override
public void onFinish() {
_context.startService(_service);
this.cancel();
Log.d(TAG, "Service AutoRebooted");
}
}
#Override
public void onReceive(Context context, Intent intent) {
if (rebootTimer == null) {
Log.d(TAG, "rebootTimer == null");
rebootTimer = new RebootTimer(10000, 10000);
rebootTimer._context = context;
Intent service = new Intent(context, SomeService.class);
rebootTimer._service = service;
rebootTimer.start();
} else {
rebootTimer.cancel();
rebootTimer.start();
Log.d(TAG, "rebootTimer is restarted");
}
}
}
Service will be auto-rebooted if time at RebootTimer (main process) expires, which means that "PREVENT AUTOREBOT" broadcast from service hasn't arrived

i found a solution .... late answer but i wanted to answer...
we can send a broadcast in the ondestroy of the service and create a receiver that receives the broadcast and starts the service again.... when it is destroyed by any reasons...

pls try following:
final Messenger mMessenger = new Messenger(new IncomingHandler());
class IncomingHandler extends Handler {
#Override
public void handleMessage(Message msg) {
switch (msg.what) {
default:
super.handleMessage(msg);
}
}
}
#Override
public void onCreate() {
super.onCreate();
makeServiceForeground();
}
#Override
public IBinder onBind(Intent arg0) {
return mMessenger.getBinder();
}
private void makeServiceForeground() {
IActivityManager am = ActivityManagerNative.getDefault();
try {
am.setProcessForeground(onBind(null), android.os.Process.myPid(), true);
} catch (RemoteException e) {
Log.e("", "cant set to foreground" + e.toString());
}
}
also need add in manifest.xml
<uses-permission android:name="android.permission.SET_PROCESS_LIMIT"/>

Android service killed immediately after start, despite calling startForeground()

I'm having a problem with my IntentService. Every time I start my service, the onDestroy() method is called as soon as the service becomes idle. I set up my service to run in the foreground, and despite this the service is still being killed right away. I have only one other activity in my application, and it is not calling stopService().
Reading the developer docs gives me the impression that calling startForeground() will allow your service to persist, even when idle, except when there is an very high demand for memory, or am I reading this wrong?
My code below:
public class FileMonitorService extends IntentService {
public int mNotifyId = 273;
public FileMonitorService(){
super("FileMonitorService");
}
#Override
protected void onHandleIntent(Intent arg0) {
}
#Override
public void onDestroy() {
Toast.makeText(this, getText(R.string.toast_service_stop), Toast.LENGTH_SHORT).show();
stopForeground(true);
super.onDestroy();
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Notification notification = new Notification(R.drawable.icon, getText(R.string.notification_short), System.currentTimeMillis());
notification.flags|=Notification.FLAG_NO_CLEAR;
Intent notificationIntent = new Intent(this, FileMonitorActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0);
notification.setLatestEventInfo(this, getText(R.string.notification_short),getText(R.string.notification_long), pendingIntent);
startForeground(mNotifyId, notification);
Toast.makeText(this, getText(R.string.toast_service_start), Toast.LENGTH_SHORT).show();
return super.onStartCommand(intent, flags, startId);
}
}

You need to look into using a regular Service instead of an IntentService. IntentService is designed to keep running while it has work to do. Once you've finished your onStartCommand method, it tries to stop.
See the docs:
Clients send requests through startService(Intent) calls; the service is started as needed, handles each Intent in turn using a worker thread, and stops itself when it runs out of work.
(Emphasis mine)