I have an issue to use service.
I am trying to use background service with permanently running. I have implemented with AlarmManager. So when app closed then send broadcast in service's OnDestroy() method. And in alarm receiver, can start service.
#Override
public int onStartCommand(Intent intent, int flags, int startId)
{
serviceInstance = this;
callHelper = new CallHelper(this);
callHelper.start();
return START_STICKY;
}
#Override
public void onDestroy() {
Log.d("1111111111", "stop service");
super.onDestroy();
setAlarmTimer();
}
#Override
public void onTaskRemoved(Intent rootIntent) {
Log.d("1111111111", "stop remove");
super.onTaskRemoved(rootIntent);
}
protected void setAlarmTimer() {
final Calendar c = Calendar.getInstance();
c.setTimeInMillis(System.currentTimeMillis());
c.add(Calendar.SECOND, 1);
Intent intent = new Intent(this, AlarmReceiver.class);
PendingIntent sender = PendingIntent.getBroadcast(this, 0,intent,0);
AlarmManager mAlarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
mAlarmManager.set(AlarmManager.RTC_WAKEUP, c.getTimeInMillis(), sender);
}
But if I remove(swipe) the app from recent app list, then service's OnDestroy() or OnTaskRemoved doesn't called. So can't call AlarmManager.
Following is my Manifest.xml:
<service
android:name=".service.CallTrackService"
android:enabled="true"
android:exported="true"
android:stopWithTask="false"/>
How to call service's OnDestory() or OnTaskRemoved() method when removing the app from recent app list?
Anyone who know this issue then please provide a solution.
The Service class has an onTaskRemoved() method which is triggered when the app is removed from the recent apps.
There the Service can call stopSelf() to shut itself down.
As in:
#Override
public void onTaskRemoved(Intent rootIntent) {
super.onTaskRemoved(rootIntent);
stopSelf();
}
edit
in android Oreo , start your service this way :
startForegroundService(new Intent(context, your_service.class));
You don't. The framework does. A bound service is destroyed when nothing is bound to it anymore. A started service is destroyed when its explicitly stopped, or when the system needs resources. To explicitly stop a service, call stopService from any Context, or stopSelf from the Service.
But "I am trying to use background service with permanently running.". Not possible in modern Android. The system will clean you up for resources. There is no way to make it permanently run, or even pseudo permanently with gaps via an alarm. Whatever it is you want your service to actually do, you need to find another way.
Related
I am starting a service (or re-starting the running service) when an activity is launched, using :
Intent intent = new Intent(this, MyService.class);
startService(intent);
Later on based on certain actions, the same activity binds to the service using
bindService(new Intent(this, MyService.class), mConnection, Context.BIND_AUTO_CREATE);
And when the activity is destroyed, I call
unbindService(mConnection);
Earlier, the service used to restart when I killed the same activity/application from the application tray and showed the "message 1 process 1 service running" under running apps.
Now, the service does not restart on killing the same activity/application.
And I get the message "0 process 1 service running", which means the service is actually not running.
The service does not restart on application being closed. My application consists of one activity. Also the service is successfully started when launched after a system boot.
Why does the process of the service gets killed when I start it using startService() ??
edit
The service used to re-start earlier after i closed the app from the application tray. But now suddenly with the SAME code, it doesn't. It happens with other apps too when i close them. eg.
Here is a workaround I came across and works well for re-starting a service if its process is killed on closing the application. In your service, add the following code.
I came across this workaround in this thread.
#Override
public void onTaskRemoved(Intent rootIntent){
Intent restartServiceIntent = new Intent(getApplicationContext(), this.getClass());
restartServiceIntent.setPackage(getPackageName());
PendingIntent restartServicePendingIntent = PendingIntent.getService(getApplicationContext(), 1, restartServiceIntent, PendingIntent.FLAG_ONE_SHOT);
AlarmManager alarmService = (AlarmManager) getApplicationContext().getSystemService(Context.ALARM_SERVICE);
alarmService.set(
AlarmManager.ELAPSED_REALTIME,
SystemClock.elapsedRealtime() + 1000,
restartServicePendingIntent);
super.onTaskRemoved(rootIntent);
}
Seems to be a bug that the process of the application is killed. There is no point for a service to run if its process is killed.
Please be aware of that: onDestroy is not always called. You should not put code that way.
When activity forced closed or closed by system abnormally, onDestroy is not getting called.
Unfortunately, this is a complicated problem due to the way Android works. There are a number of strategies that each work around different parts of the problem. For best results, combine multiple strategies together.
Note that some of these strategies may no longer be necessary in more recent Android versions.
1. Start an activity
What to do
Taken from Foreground service killed when receiving broadcast after acitivty swiped away in task list:
In the foreground service:
#Override
public void onTaskRemoved( Intent rootIntent ) {
Intent intent = new Intent( this, DummyActivity.class );
intent.addFlags( Intent.FLAG_ACTIVITY_NEW_TASK );
startActivity( intent );
}
In the manifest:
<activity
android:name=".DummyActivity"
android:theme="#android:style/Theme.NoDisplay"
android:enabled="true"
android:allowTaskReparenting="true"
android:noHistory="true"
android:excludeFromRecents="true"
android:alwaysRetainTaskState="false"
android:stateNotNeeded="true"
android:clearTaskOnLaunch="true"
android:finishOnTaskLaunch="true"
/>
(If your service is in a different process then set this activity's process to the same one.)
In DummyActivity.java:
public class DummyActivity extends Activity {
#Override
public void onCreate( Bundle icicle ) {
super.onCreate( icicle );
finish();
}
}
Side effects
Causes the recents activity to close. Normally, swiping away an app doesn't close the recents activity.
Disadvantages
This only takes effect when the dummy activity starts, which may take half a second or more, so this still leaves the service open to being killed for a bit.
Explanation
When you remove/swipe your app away, a flag called waitingToKill is set. While this flag is set, Android may kill the process at any point in the future, such as when you receive a broadcast. Starting an activity clears this flag.
2. Spam a BroadcastReceiver with foreground broadcasts
What to do
Merge this into your service code:
if (Build.VERSION.SDK_INT >= 16) {
Intent intent = new Intent(this, DummyReceiver.class);
intent.addFlags(Intent.FLAG_RECEIVER_FOREGROUND);
//This seems to be timing-related; the more times we do this,
//the less likely the process gets killed
for (int i = 0; i < 50; ++i)
sendBroadcast(intent);
}
Create a dummy broadcast receiver:
public class DummyReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {}
}
Add the receiver to your manifest:
<receiver android:name=".DummyReceiver" />
Side effects
May cause a slight (~250ms) delay/hang when the task is removed from the recents screen.
Disadvantages
This only keeps the process alive while it is receiving the broadcasts. the waitingToKill flag is still set, so the process may still be killed afterwards, such as when a broadcast is received.
Explanation
If your process isn't running in foreground priority, Android will try to kill it immediately. Receiving foreground broadcasts temporarily prevents this, resulting in the waitingToKill flag being set instead.
3. Don't bind to services
Binding to a service seems to increase the likelihood of the service's process being killed immediately when a task is removed.
I know this question is old but I recently encountered this problem and suddenly my service get stopped on closing app. Earlier it was working fine. This problem wasted my lot of time. To others who have similar problem make sure that YOUR BACKGROUND DATA RESTRICTION IS OFF.
This was the problem I had and it actually makes sense as when background data is Restricted background process won't run.
onDestroy is not always called. The Main problem in your case is ur unable to start the service when app closed,that time android OS(In Some OS) will kill the service, If you are not able to restart the service then call a alarm manger to start the reciver like this,
Manifest is,
<service
android:name=".BackgroundService"
android:description="#string/app_name"
android:enabled="true"
android:label="Notification" />
<receiver android:name="AlarmReceiver">
<intent-filter>
<action android:name="REFRESH_THIS" />
</intent-filter>
</receiver>
IN Main Activty start alarm manger in this way,
String alarm = Context.ALARM_SERVICE;
AlarmManager am = (AlarmManager) getSystemService(alarm);
Intent intent = new Intent("REFRESH_THIS");
PendingIntent pi = PendingIntent.getBroadcast(this, 123456789, intent, 0);
int type = AlarmManager.RTC_WAKEUP;
long interval = 1000 * 50;
am.setInexactRepeating(type, System.currentTimeMillis(), interval, pi);
this will call reciver and reciver is,
public class AlarmReceiver extends BroadcastReceiver {
Context context;
#Override
public void onReceive(Context context, Intent intent) {
this.context = context;
System.out.println("Alarma Reciver Called");
if (isMyServiceRunning(this.context, BackgroundService.class)) {
System.out.println("alredy running no need to start again");
} else {
Intent background = new Intent(context, BackgroundService.class);
context.startService(background);
}
}
public static boolean isMyServiceRunning(Context context, Class<?> serviceClass) {
ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningServiceInfo> services = activityManager.getRunningServices(Integer.MAX_VALUE);
if (services != null) {
for (int i = 0; i < services.size(); i++) {
if ((serviceClass.getName()).equals(services.get(i).service.getClassName()) && services.get(i).pid != 0) {
return true;
}
}
}
return false;
}
}
And this Alaram reciver calls once when android app is opened and when app is closed.SO the service is like this,
public class BackgroundService extends Service {
private String LOG_TAG = null;
#Override
public void onCreate() {
super.onCreate();
LOG_TAG = "app_name";
Log.i(LOG_TAG, "service created");
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.i(LOG_TAG, "In onStartCommand");
//ur actual code
return START_STICKY;
}
#Override
public IBinder onBind(Intent intent) {
// Wont be called as service is not bound
Log.i(LOG_TAG, "In onBind");
return null;
}
#TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH)
#Override
public void onTaskRemoved(Intent rootIntent) {
super.onTaskRemoved(rootIntent);
Log.i(LOG_TAG, "In onTaskRemoved");
}
#Override
public void onDestroy() {
super.onDestroy();
Log.i(LOG_TAG, "In onDestroyed");
}
}
when there is no binding to a service or well established foreground then android system recognize the service as unused overloading service that should be shut down. Here is the best way to maintain your service even if the app is closed: AlarmManager or Service
I have a service (properly declared in the Manifest file) that upon onDestroy() schedules itself to start again one minute later via AlarmManager. However the service is not starting even though onDestroy() runs correctly. What could be wrong?
The scheduling code:
#Override
public void onDestroy() {
BroadcastReceiver br = new BroadcastReceiver() {
#Override
public void onReceive(Context c, Intent i) {
c.startService(new Intent(c, MyService.class));
}
};
registerReceiver(br, new IntentFilter("xxxx"));
PendingIntent pi = PendingIntent.getBroadcast(this, 0, new Intent("xxxx"), 0);
AlarmManager am = (AlarmManager)(this.getSystemService(Context.ALARM_SERVICE));
am.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, SystemClock.elapsedRealtime() + ONE_MINUTE, pi);
Log.i("onDestroy", "Service scheduled.");
unregisterReceiver(br);
super.onDestroy();
}
The service declaration in the Manifest file:
<service
android:name="com.xxxx.MyService"
android:exported="true">
</service>
First, your BroadcastReceiver is going away nanoseconds after the end of onDestroy(), making it useless. Please register your BroadcastReceiver in the manifest with a <receiver> element.
Second, a _WAKEUP alarm only keeps the device awake long enough to process an onReceive() in a BroadcastReceiver. You need to use a WakeLock to keep the device awake longer than that. Depending upon what you are doing, my WakefulIntentService may be of some use.
Third, you do not need to export your service, and by doing so, you are opening up potential security holes. I recommend removing android:exported="true".
I am starting a service from my main Android activity as follows:
final Context context = base.getApplicationContext();
final Intent intent = new Intent(context, MyService.class);
startService(intent);
When I close the activity page by swiping it out from the recent apps list, the service stops running and restarts after some time. I can't use persistent services with notifications because of my app requirements. How can I make the service NOT restart or shutdown and just keep on running on app exit?
I'm in the same situation, so far I learned when the app is closed the service get closed also because they are in a one thread, so the service should be on another thread in order fot it not to be closed, look into that and look into keeping the service alive with alarm manager here an example http://www.vogella.com/articles/AndroidServices/article.html this way your service won't be shown in notification.
lastly, after all the research I've done I'm coming to realize that the best choice for a long running service is startForeground(), because it is made for that and the system actually deals with your service well.
make you service like this in your Mainifest
<service
android:name=".sys.service.youservice"
android:exported="true"
android:process=":ServiceProcess" />
then your service will run on other process named ServiceProcess
if you want make your service never die :
onStartCommand() return START_STICKY
onDestroy() -> startself
create a Deamon service
jin -> create a Native Deamon process, you can find some open-source projects on github
startForeground() , there is a way to startForeground without Notification ,google it
Services are quite complicated sometimes.
When you start a service from an activity (or your process), the service is essentially on the same process.
quoting from the developer notes
Most confusion about the Service class actually revolves around what it is not:
A Service is not a separate process. The Service object itself does not imply it is running in its own process; unless otherwise specified, it runs in the same process as the application it is part of.
A Service is not a thread. It is not a means itself to do work off of the main thread (to avoid Application Not Responding errors).
So, what this means is, if the user swipes the app away from the recent tasks it will delete your process(this includes all your activities etc).
Now, lets take three scenarios.
First where the service does not have a foreground notification.
In this case your process is killed along with your service.
Second where the service has a foreground notification
In this case the service is not killed and neither is the process
Third scenario
If the service does not have a foreground notification, it can still keep running if the app is closed. We can do this by making the service run in a different process.
(However, I've heard some people say that it may not work. left to you to try it out yourself)
you can create a service in a separate process by including the below attribute
in your manifest.
android:process=":yourService"
or
android:process="yourService" process name must begin with lower case.
quoting from developer notes
If the name assigned to this attribute begins with a colon (':'), a new process, private to the application, is created when it's needed and the service runs in that process. If the process name begins with a lowercase character, the service will run in a global process of that name, provided that it has permission to do so. This allows components in different applications to share a process, reducing resource usage.
this is what I have gathered, if anyone is an expert, please do correct me if I'm wrong :)
This may help you. I may be mistaken but it seems to me that this is related with returning START_STICKY in your onStartCommand() method. You can avoid the service from being called again by returning START_NOT_STICKY instead.
The Main problem is in unable to start the service when app closed, android OS(In Some OS) will kill the service for Resource Optimization, If you are not able to restart the service then call a alarm manger to start the receiver like this,Here is the entire code, This code will keep alive ur service.
Manifest is,
<service
android:name=".BackgroundService"
android:description="#string/app_name"
android:enabled="true"
android:label="Notification" />
<receiver android:name="AlarmReceiver">
<intent-filter>
<action android:name="REFRESH_THIS" />
</intent-filter>
</receiver>
IN Main Activty start alarm manger in this way,
String alarm = Context.ALARM_SERVICE;
AlarmManager am = (AlarmManager) getSystemService(alarm);
Intent intent = new Intent("REFRESH_THIS");
PendingIntent pi = PendingIntent.getBroadcast(this, 123456789, intent, 0);
int type = AlarmManager.RTC_WAKEUP;
long interval = 1000 * 50;
am.setInexactRepeating(type, System.currentTimeMillis(), interval, pi);
this will call reciver and reciver is,
public class AlarmReceiver extends BroadcastReceiver {
Context context;
#Override
public void onReceive(Context context, Intent intent) {
this.context = context;
System.out.println("Alarma Reciver Called");
if (isMyServiceRunning(this.context, BackgroundService.class)) {
System.out.println("alredy running no need to start again");
} else {
Intent background = new Intent(context, BackgroundService.class);
context.startService(background);
}
}
public static boolean isMyServiceRunning(Context context, Class<?> serviceClass) {
ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningServiceInfo> services = activityManager.getRunningServices(Integer.MAX_VALUE);
if (services != null) {
for (int i = 0; i < services.size(); i++) {
if ((serviceClass.getName()).equals(services.get(i).service.getClassName()) && services.get(i).pid != 0) {
return true;
}
}
}
return false;
}
}
And this Alaram reciver calls once when android app is opened and when app is closed.SO the service is like this,
public class BackgroundService extends Service {
private String LOG_TAG = null;
#Override
public void onCreate() {
super.onCreate();
LOG_TAG = "app_name";
Log.i(LOG_TAG, "service created");
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.i(LOG_TAG, "In onStartCommand");
//ur actual code
return START_STICKY;
}
#Override
public IBinder onBind(Intent intent) {
// Wont be called as service is not bound
Log.i(LOG_TAG, "In onBind");
return null;
}
#TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH)
#Override
public void onTaskRemoved(Intent rootIntent) {
super.onTaskRemoved(rootIntent);
Log.i(LOG_TAG, "In onTaskRemoved");
}
#Override
public void onDestroy() {
super.onDestroy();
Log.i(LOG_TAG, "In onDestroyed");
}
}
From Android O, you cant use the services for the long running background operations due to this, https://developer.android.com/about/versions/oreo/background . Jobservice will be the better option with Jobscheduler implementation.
try this, it will keep the service running in the background.
BackServices.class
public class BackServices extends Service{
#Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return null;
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
// Let it continue running until it is stopped.
Toast.makeText(this, "Service Started", Toast.LENGTH_LONG).show();
return START_STICKY;
}
#Override
public void onDestroy() {
super.onDestroy();
Toast.makeText(this, "Service Destroyed", Toast.LENGTH_LONG).show();
}
}
in your MainActivity onCreate drop this line of code
startService(new Intent(getBaseContext(), BackServices.class));
Now the service will stay running in background.
Using the same process for the service and the activity and START_STICKY or START_REDELIVER_INTENT in the service is the only way to be able to restart the service when the application restarts, which happens when the user closes the application for example, but also when the system decides to close it for optimisations reasons. You CAN NOT have a service that will run permanently without any interruption. This is by design, smartphones are not made to run continuous processes for long period of time. This is due to the fact that battery life is the highest priority. You need to design your service so it handles being stopped at any point.
You must add this code in your Service class so that it handles the case when your process is being killed
#Override
public void onTaskRemoved(Intent rootIntent) {
Intent restartServiceIntent = new Intent(getApplicationContext(), this.getClass());
restartServiceIntent.setPackage(getPackageName());
PendingIntent restartServicePendingIntent = PendingIntent.getService(getApplicationContext(), 1, restartServiceIntent, PendingIntent.FLAG_ONE_SHOT);
AlarmManager alarmService = (AlarmManager) getApplicationContext().getSystemService(Context.ALARM_SERVICE);
alarmService.set(
AlarmManager.ELAPSED_REALTIME,
SystemClock.elapsedRealtime() + 1000,
restartServicePendingIntent);
super.onTaskRemoved(rootIntent);
}
Why not use an IntentService?
IntentService opens a new Thread apart from the main Thread and works there, that way closing the app wont effect it
Be advised that IntentService runs the onHandleIntent() and when its done the service closes, see if it fits your needs.
http://developer.android.com/reference/android/app/IntentService.html
Best solution is to use the sync Adapter in android to start the service. Create a Sync Adapter and call start service their.. inside onPerformSync method. to create sync Account please refer this link https://developer.android.com/training/sync-adapters/index.html
Why SyncAdapter? Ans: Because earlier you used to start the service using your App context. so whenever your app process get killed (When u remove it from task manager or OS kill it because of lack of resources ) at that time your service will also be removed. SyncAdapter will not work in application thread.. so if u call inside it.. service will no longer be removed.. unless u write code to remove it.
<service android:name=".Service2"
android:process="#string/app_name"
android:exported="true"
android:isolatedProcess="true"
/>
Declare this in your manifest. Give a custom name to your process and make that process isolated and exported .
Running an intent service will be easier. Service in creating a thread in the application but it's still in the application.
Just override onDestroy method in your first visible activity like after splash you have home page and while redirecting from splash to home page you have already finish splash. so put on destroy in home page. and stop service in that method.
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)
I have a task to periodically read the phone sensors (e.g. WiFi, accelerometer) in the backend.
My current solution is to use an AlarmManager.
Specifically, we have:
In the "main" program (an activity), we use PendingIntent.getService:
public class Main extends Activity {
...
Intent intent = new Intent(this, AutoLogging.class);
mAlarmSender = PendingIntent.getService(this, 0, intent, 0);
am = (AlarmManager)getSystemService(ALARM_SERVICE);
am.setRepeating(AlarmManager.RTC, 0, 5*1000, mAlarmSender);
}
In the "AutoLogging" program (a service), we respond to the alarm periodically:
public class AutoLogging extends Service {
...
#Override
public void onCreate() {
Toast.makeText(this, "onCreate", Toast.LENGTH_SHORT).show();
}
#Override
public void onDestroy() {
super.onDestroy();
Toast.makeText(this, "onDestroy", Toast.LENGTH_SHORT).show();
}
#Override
public boolean onUnbind(Intent intent) {
Toast.makeText(this, "onUnbind", Toast.LENGTH_SHORT).show()
return super.onUnbind(intent);
}
#Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
Toast.makeText(this, "onStart", Toast.LENGTH_SHORT).show();
// Read sensor data here
}
#Override
public IBinder onBind(Intent intent) {
Toast.makeText(this, "onBind", Toast.LENGTH_SHORT).show();
return null;
}
}
My problem is:
When I use this alarm service, only OnCreate and OnStart are called at each alarm.
My questions are:
(1) Do we need to call OnDestroy (or onBind, onUnbind)?
(2) Is this a correct way to use AlarmManager (compared with "broadcase receiver")?
Thanks!
Vincent
AlarmManager just uses the pending intent and performs the intent action, i.e starting service in your case.On alarm expiry service is created using onCreate( if it is not already running ) and then started by calling onStart. After you finish reading the sensor data, you can stop the service using stopSelf() which will ultimately call onDestroy().You shouldn't call onDestroy(),onBind() or onUnBind() explicitly in the service.
If you use broadcast receiver with alarm manager you have to start this service in onReceive of receiver.Using Service seems appropriate to me in this case.
If you want to schedule a job in android periodically instead of using an alarm manager you can use GCM network manager with the periodic task. This internally uses an alarm manager or job scheduler depending on the Android version. It is also easier to use with a more flexible option.
This article is great -
https://www.bignerdranch.com/blog/optimize-battery-life-with-androids-gcm-network-manager/
Chiming in years late for anyone that stumbles upon this.
In terms of which method gets called when for services see this post here:
Android onCreate or onStartCommand for starting service
You'd want to trigger in the onStartCommand.