Develop Reference

Want to make a persistent service like Whatsapp/Truecaller

Description of Truecaller/Whatsapp service
**Note: Here force close means killing the app by pressing and holding back button not just stopping the service from service manager/app manager (see Kill app back button).
After killing the truecaller app when I make a call it restarts automatically, same for whatsapp also, After killing it when a message is received it still shows the notification and restarts the service. These services also restarts after a few delay
What I have done so far to achieve this
I want to make a service like this so called my backgroundservice from onDestroy() of my backgroundservice class. Code for this: ServiceDemo 0.1
public class BackgroundService extends Service {
#Nullable
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Toast.makeText(BackgroundService.this, "Service Started...", Toast.LENGTH_SHORT).show();
return START_STICKY;
}
#Override
public void onDestroy() {
Intent intentService = new Intent(this,BackgroundService.class);
startService(intentService);
Toast.makeText(BackgroundService.this, "Service Will Be Restarted...", Toast.LENGTH_SHORT).show();
}
}
The service is restarting if I stop it from my service manager. But if I force close/kill it , it's gone.
After this I implemented Broadcast receiver which doesn't make any difference. Code for this: ServiceDemo 0.2
BackgroundService.java
public class BackgroundService extends Service {
#Nullable
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Toast.makeText(BackgroundService.this, "Service Started...", Toast.LENGTH_SHORT).show();
return START_STICKY;
}
#Override
public void onDestroy() {
Toast.makeText(BackgroundService.this, "Service Will Be Restarted...", Toast.LENGTH_SHORT).show();
sendBroadcast(new Intent("RestartMe"));
}
}
RestartBackgroundService.java
public class RestartBackgroundService extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
// I have also used AlarmManager , but it doesn't make any difference for me
// AlarmManager am = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
// PendingIntent pi = PendingIntent.getService(context, 0, new Intent(context, BackgroundService.class), PendingIntent.FLAG_UPDATE_CURRENT);
// int interval = 5000;
// am.setInexactRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + interval, interval, pi);
context.startService(new Intent(context.getApplicationContext(),BackgroundService.class));
}
}
As whatsapp is using gcm so I thought if I implement that it would help.
Then I implemented firebase cloud messaging (fcm) to receive push notification and I removed the code to restart background service from onDestroy().
Now if I stops the service from service manager it remains stopped then I sends a notification from my firebase console it receives the notification as google's gcm service is running. If I click the notification it restarts my service again.
But if I force close/kill my app no notifications are received though gcm service is running. Code for this: (I posted a link to make the description a bit short)
ServiceDemo 0.3
What I want
I want my service to be persistent like whatsapp/truecaller even if I force close it. They keep on starting after a few delays. And I want to achieve it without using third parties like fcm.
If someone can give any hints/solution about how to start my service when a particular system service/app (like dialer) starts that would be a great help.

Replace Service with AlarmManager in Android

I have an android service to fetch data from the web that runs every fifteen minutes
public class SparkService extends Service {
Handler handler;
public SparkService() {
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.e("Starting Sevice", "Starting Service Successfully.");
if (handler == null) {
handler = new Handler(new Handler.Callback() {
#Override
public boolean handleMessage(Message msg) {
fetchDataFromServer();
handler.removeMessages(120);
handler.sendEmptyMessageDelayed(120, 15 * 60 * 1000);
return true;
}
});
}
handler.sendEmptyMessageDelayed(120, 15 * 60 * 1000);
return Service.START_STICKY;
}
}
I have found the service to be unreliable at times and seems like it's not being called if the app is inactive for a certain period of time. I want to replace the service with an AlarmManager service instead. My app is currently in production. Can I just delete the SparkService class and add another Alarm service class without affecting existing users who update the app? Or would I have to stop this SparkService in my app update so the app can function properly?

Your app is your entry point. So if it's killed that means all services related to its process will also be killed, like if you kill the svchost.exe process in Windows all sub processes like Windows update service will be stopped too and will not be running again until you launch the update manager.
The same goes for your app: the only way that a Service won't be stopped by killing your app (and I'm not sure about that but it can be) is if the Service is created with its own process using a special tag in the Manifest.
I think in your case you didn't set that tag so the Service will be only scheduled once your app is launched after the update and in that case the Service will behave according to the new code.

To answer your first question even if you delete the service from your update users with the old version will not be affected until they update there version with the new one
Now for using Alarm manger to trigger update from your backend as you said it's a good practice as the alarm manager have different set that you can use depending or your need below a short example how to use it
// Get alarm manager instance
AlarmManager alarmManager = (AlarmManager)getApplicationContext().getSystemService(Context.ALARM_SERVICE);
Calendar calendar;
Intent intent;
PendingIntent pendingIntent;
// Schedule
intent = new Intent(getApplicationContext(), YourCustomBroadcastReceiver.class);
pendingIntent = PendingIntent.getBroadcast(getApplicationContext(), 0, intent, 0);
calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
calendar.add(Calendar.SECOND, 1); // first time
alarmManager.setRepeating(
AlarmManager.RTC_WAKEUP,
calendar.getTimeInMillis(),
60*5*1000,//Each five minutes
pendingIntent
);
And in your broadcast receiver
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
public class YourBroadcastReceiver extends BroadcastReceiver{
publicYourBroadcastReceiver() {}
#Override
public void onReceive(Context context, Intent intent) {
Intent serviceIntent = new Intent(context.getApplicationContext(),YourService.class);
context.startService(serviceIntent);
}
}
And here for more details about alarm manager
http://developer.android.com/training/scheduling/alarms.html

Restarting a service in the onDestroy method

I have made an app in which a service runs in the background. But if the android system requires resources, it will stop the service. However I may still require my service to run.
Is it a bad practice to restart the service (if condition relevant to my app still holds true) in the onDestroy method of my service?
How can I make sure my service runs indefinitely (if condition relevant to my app still holds true)? Or atleast on high priority?

Probably the best you can do is use the START_STICKY flag, which tells Android to attempt to restart the service if it has stopped. Beyond that ensure that it consumes as few resources as possible, so that it is less likely to be destroyed.
Android prioritizes the UI over everything. Then processes that are related to the UI. Then processes that are consuming the least amount of resources. A Service runs in the background, so unless it has resources that are also in use on the UI or connected to the UI in some way, it should be a lower priority.
Also you cannot tell Android how to prioritize your Service (everyone would make theirs the "highest priority" right?). So it goes by how well you minimize the impact on overall resources - why kill 3 Services when it could kill 1 and regain all the resources it needs?
To help understand how to manage memory better: http://developer.android.com/training/articles/memory.html

set it START_STICKY. It Causes after killing service the service will restart again. it is my code :
android manifest :
<application
....
<service android:name=".UpdateService" />
</application>
service class :
import android.app.Service;
import android.content.BroadcastReceiver;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.IBinder;
import android.util.Log;
import android.widget.Toast;
public class UpdateService extends Service {
BroadcastReceiver mReceiver;
#Override
public void onCreate() {
super.onCreate();
// register receiver that handles screen on and screen off logic
IntentFilter filter = new IntentFilter(Intent.....);
filter.addAction(Intent....);
mReceiver = new MyReceiver();
registerReceiver(mReceiver, filter);
}
#Override
public void onDestroy() {
unregisterReceiver(mReceiver);
Log.i("onDestroy Reciever", "Called");
super.onDestroy();
}
#Override
public void onStart(Intent intent, int startId) {
Log.i("log", "action Called");
}
}
#Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
return null;
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
return Service.START_STICKY;
}
}
receiver class :
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
public class MyReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Log.i("Log", "recevid");
}
}
in StartupActivity :
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Context context = getApplicationContext();
Intent service = new Intent(context, UpdateService.class);
context.startService(service);
}

Android - Periodic Background Service - Advice

I am working on an app that will relay information about its location to a remote server. I am intending to do it by doing a simple HTTP post to the web-server and all is simple and fine.
But according to the spec, the app needs to execute itself from time to time, lets say once in every 30 mins. Be independent of the interface, meaning which it needs to run even if the app is closed.
I looked around and found out that Android Services is what needs to be used. What could I use to implement such a system. Will the service (or other mechanism) restart when the phone restarts?
Thanks in advance.

Create a Service to send your information to your server. Presumably, you've got that under control.
Your Service should be started by an alarm triggered by the AlarmManager, where you can specify an interval. Unless you have to report your data exactly every 30 minutes, you probably want the inexact alarm so you can save some battery life.
Finally, you can register your app to get the bootup broadcast by setting up a BroadcastReceiver like so:
public class BootReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(Intent.ACTION_BOOT_COMPLETED)) {
// Register your reporting alarms here.
}
}
}
You'll need to add the following permission to your AndroidManifest.xml for that to work. Don't forget to register your alarms when you run the app normally, or they'll only be registered when the device boots up.
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>

Here is a semi-different way to keep the service going forever. There is ways to kill it in code if you'd wish
Background Service:
package com.ex.ample;
import android.app.Service;
import android.content.*;
import android.os.*;
import android.widget.Toast;
public class BackgroundService extends Service {
public Context context = this;
public Handler handler = null;
public static Runnable runnable = null;
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public void onCreate() {
Toast.makeText(this, "Service created!", Toast.LENGTH_LONG).show();
handler = new Handler();
runnable = new Runnable() {
public void run() {
Toast.makeText(context, "Service is still running", Toast.LENGTH_LONG).show();
handler.postDelayed(runnable, 10000);
}
};
handler.postDelayed(runnable, 15000);
}
#Override
public void onDestroy() {
/* IF YOU WANT THIS SERVICE KILLED WITH THE APP THEN UNCOMMENT THE FOLLOWING LINE */
//handler.removeCallbacks(runnable);
Toast.makeText(this, "Service stopped", Toast.LENGTH_LONG).show();
}
#Override
public void onStart(Intent intent, int startid) {
Toast.makeText(this, "Service started by user.", Toast.LENGTH_LONG).show();
}
}
Here is how you start it from your main activity or wherever you wish:
startService(new Intent(this, BackgroundService.class));
onDestroy() will get called when the application gets closed or killed but the runnable just starts it right back up.
I hope this helps someone out.
The reason why some people do this is because of corporate applications where in some instances the users/employees must not be able to stop certain things :)
http://i.imgur.com/1vCnYJW.png
EDIT
Since Android O (8.0) you have to use JobManager for scheduled tasks. There is a library called Android-Job by Evernote which will make periodic background work a breeze on all Android versions. I have also made a Xamarin Binding of this library.
Then all you need to do is the following:
In your application class:
public class MyApp extends Application {
#Override
public void onCreate() {
super.onCreate();
JobManager.create(this).addJobCreator(new MyJobCreator());
}
}
Create the following two classes YourJobCreator and YourSyncJob(Where all the work will be done. Android allocates time for all the background jobs to be run. For android versions < 8.0 it will still run with an Alarm manager and background service as per normal)
public class MyJobCreator implements JobCreator {
#Override
#Nullable
public Job create(#NonNull String tag) {
switch (tag) {
case MySyncJob.TAG:
return new MySyncJob();
default:
return null;
}
}
}
public class MySyncJob extends Job {
public static final String TAG = "my_job_tag";
#Override
#NonNull
protected Result onRunJob(Params params) {
//
// run your job here
//
//
return Result.SUCCESS;
}
public static void scheduleJob() {
new JobRequest.Builder(MySyncJob.TAG)
.setExecutionWindow(30_000L, 40_000L) //Every 30 seconds for 40 seconds
.build()
.schedule();
}
}

You should schedule your service with alarm manager, first create the pending intent of service:
Intent ii = new Intent(getApplicationContext(), MyService.class);
PendingIntent pii = PendingIntent.getService(getApplicationContext(), 2222, ii,
PendingIntent.FLAG_CANCEL_CURRENT);
Then schedule it using alarm manager:
//getting current time and add 5 seconds to it
Calendar cal = Calendar.getInstance();
cal.add(Calendar.SECOND, 5);
//registering our pending intent with alarmmanager
AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
am.set(AlarmManager.RTC_WAKEUP,cal.getTimeInMillis(), pi);
this will launch your service after 5 seconds of current time. You can make your alarm repeating.

You can use Alarm Manager to start Service at specified time and then repeat alarm in specified interval. When alarm goes on you can start service and connect to server and make what you want

Stop unBound service in Android

I have a service that autoupdates a database in a given time interval. To do this it gets information from the Internet.
I need to have it unbound, so that It runs over all activities. But when the application is closed, it would be nice to terminate the service. To prevent battery drain. How can this be achieved?

I think that you should let your service be started by a boot broadcastReceiver, then ask AlarmManager to relaunch it every now and then.
public class DbUpdateService extends Service {
//compat to support older devices
#Override
public void onStart(Intent intent, int startId) {
onStartCommand(intent, 0, startId);
}
#Override
public int onStartCommand (Intent intent, int flags, int startId){
//your method to update the database
UpdateTheDatabaseOnceNow();
//reschedule me to check again tomorrow
Intent serviceIntent = new Intent(DbUpdateService.this,DbUpdateService.class);
PendingIntent restartServiceIntent = PendingIntent.getService(DbUpdateService.this, 0, serviceIntent,0);
AlarmManager alarms = (AlarmManager)getSystemService(ALARM_SERVICE);
// cancel previous alarm
alarms.cancel(restartServiceIntent);
// schedule alarm for today + 1 day
Calendar calendar = Calendar.getInstance();
calendar.add(Calendar.DATE, 1);
// schedule the alarm
alarms.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), restartServiceIntent);
return Service.START_STICKY;
}
}
To start your service at boot time use this :
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
public class serviceAutoLauncher extends BroadcastReceiver{
#Override
public void onReceive(Context context, Intent intent) {
Intent serviceIntent = new Intent(context,DbUpdateService.class);
context.startService(serviceIntent);
}
}
Finally add this to your manifest to schedule your serviceAutoLauncher to be launched at each boot:
<receiver android:name="serviceAutoLauncher">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED"></action>
<category android:name="android.intent.category.HOME"></category>
</intent-filter>
</receiver>

Use the stopService method.

It depends on how you start the service. If you start it when your Activity is opened, then call stopService in your Activities onDestroy().