Develop Reference

Reasons why a service could be stopped in android

If I have an app that does not have any activities, just one BOOT_COMPLETED broadcast receiver and the simplest service. The receiver will just start the service and the service will just ran the following code:
public class ScreenStateService 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) {
return START_STICKY;
}
#Override
public void onCreate() {
super.onCreate();
}
}
As as I understand, the service would ran until the end of time or until one of the following scenarios occurr:
Low memory: The system is running low on memory so it decides to stop the service.
ANR
The user manually stops the application or disables it.
In 1 and 2 the system would start the service again, after memory is no longer low or after the error is handled. In the case of 3 it wont be started again.
The question is: is the above right? Are there any other cases where the service would be stopped by an outside source? Please specify if it would be started again automatically if there are any.

Best approach to execute service in Android

I have a service that have an variable life time. It may execute from 5 minutes to 2 hours (for example). So I'm looking for the best approach to do that, and my service must achieve the following features:
Send (to my server) lat-long every 5 seconds and some extra information (string's, boolean's and int's)
I have tried a "normal" service and tried to do something like this to achieve this:
public class MyFiveSecondsService extends Service {
private Handler handler;
Runnable r = new Runnable() {
#Override
public void run() {
//here send my new data
}
};
public void onCreate(){
super.onCreate();
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
if(handler == null){
handler = new Handler();
}
handler.post(r);
return super.onStartCommand(intent, flags, startId);
}
}
Actually that code works, but I got some performance problems with that approach, so I tried to do something like this:
public class SendUniquePositionIntentService extends IntentService {
public SendUniquePositionIntentService() {
super("co.bomboapp.Service.IntentService.SendUniquePositionIntentService");
}
#Override
public void onCreate() {
super.onCreate();
}
#Override
protected void onHandleIntent(Intent intent) {
//do the logic here
}
}
public class MyFiveSecondsService extends Service {
private Handler handler;
Runnable r = new Runnable() {
#Override
public void run() {
//call my SendUniquePositionIntentService here
}
};
public void onCreate(){
super.onCreate();
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
if(handler == null){
handler = new Handler();
}
handler.post(r);
return super.onStartCommand(intent, flags, startId);
}
}
And that approach haven't worked, when I had closed the app any service kept running. So before start any other attempt to achieve this, I want some direction, what's the best approach to do this "infinite loop service" and keep the performance?
I'm using Android 4.1 as min API, and targeting 5.0 API.
My test device is a Nexus 5 running Android 6.
Right now I'm using parse.com as database.

"I have tried a "normal" service...but I got some performance problems"
By default, a service runs on the application's main thread, so when you create a handler with
public int onStartCommand(Intent intent, int flags, int startId) {
if(handler == null){
handler = new Handler();
}
...
}
the handler is associated with the main thread's Looper and all messages and runnables are delivered and later executed on the thread. That's the reason of the "performance problems". From the documentation:
Remember that if you do use a service, it still runs in your application's main thread by default...
Regarding the second approach and the part
"...when I had closed the app any service kept running"
you haven't mentioned how exactly you "close" the app, but what I can see is
public int onStartCommand(Intent intent, int flags, int startId) {
...
return super.onStartCommand(intent, flags, startId);
}
which means that if the system kills the service it, by default, will be recreated. So if "closing" your app means killing it, the following chain of actions takes place:
The system recreates MyFiveSecondsService,
onStartCommand() is called and the handler posts the runnable
within the run() method SendUniquePositionIntentService is started
From the documentation of onStartCommand():
the default implementation calls onStart(Intent, int) and returns either START_STICKY or START_STICKY_COMPATIBILITY.
Note that starting a service from another one (like starting SendUniquePositionIntentService from MyFiveSecondsService in your case) is redundant unless you intended to.
The final part of your question is confusing to me. On one hand it doesn't work for you because "...any service kept running" but, on the other hand, you'd like "do this "infinite loop service""...?
If you only need to send such information as "strings, booleans and ints" to a server (without any feedback to the component that started the service), I suppose it's simply enough for you to use IntentService. This is a "out-of-box" framework that does its work on a background thread (letting you avoid freezing the main thread) and stops itself once it's done. As an example you can use the documentation on IntentService - it's well written.
Also note that the behaviour of a service after killing it by the system depends on the flag returned by onStartCommand(). E.g. use START_NOT_STICKY to not recreate the service after killing the app or START_REDELIVER_INTENT to recreate it with the last Intent redelivered.

Always runs service in background on Android?

I am building an app which has a background service for continuously communicating with a Raspberry Pi.
I am making the service sticky(Service.START_STICKY) so that is will restart when it's killed by user or OS.
This works well for the first 30-40 minuten. After 30-40 minutes the services seems to be stopped.
Isn't there any way to avoid this problem? I know it's bad for the batterylife if there is service continiously runnnig in the background. The app is used in my own project to automate my room and is only used by me. So the batterylife isn't a problem.
public class RaspberryPiCommunication extends Service {
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
//Do continuouswork here in a seperate thread
return Service.START_STICKY;
}
}
I also have another quetions about service:
If the service is started twice in the following example, will there be two instances of SomeObject() and is doSomWork() running twice in background?
public class RaspberryPiCommunication extends Service {
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
SomeObject obj = new SomeObject();
obj.doSomeWork();
return Service.START_STICKY;
}
}

Are you running the service on its own thread ? By default, A service runs on the main thread. For a long running task like this run it in a separate thread
Note that services, like other application objects, run in the main thread of their hosting process. This means that, if your service is going to do any CPU intensive (such as MP3 playback) or blocking (such as networking) operations, it should spawn its own thread in which to do that work.
Service will run only in one Instance. onStartCommand() is called every time you start the service.
http://developer.android.com/guide/components/services.html#StartingAService

Here is required piece of code.
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
// TODO Auto-generated method stub
handler.postDelayed(runnable, 1000 );// 1000 - Milliseconds
if (appContext == null) {
appContext = getBaseContext();
}
Toast.makeText(appContext, "Services Started", Toast.LENGTH_SHORT).show();
return START_STICKY;
}
Runnable runnable = new Runnable(){
#Override
public void run() {
// TODO Auto-generated method stub
DoBackgroundTasks();
handler.postDelayed(this, 1000 ); // 1000 - Milliseconds
}
};
void DoBackgroundTasks()
{
//write code here.
}

In your manifest where you have declared your service, add this
android:process="remote"

create background services in android

i created a simple services, its job is to handle the incoming call. I created a services like below
public class CalldetectorService extends Service {
private CallHelper callHelper;
#Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return null;
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
int res = super.onStartCommand(intent, flags, startId);
callHelper = new CallHelper(this);
return res;
}
#Override
public void onDestroy() {
super.onDestroy();
//callHelper.stop();
}
}
Inside the helper, i m handling the call. This service is not running in background continuously. after some time, its getting halted. It works pretty well when i open app & move to background for some time, later on it wont work.
How to make my service to work in background always and catch the incoming calls

If you don't want the service to be killed by the OS: A started service can use the startForeground(int, Notification) API to put the service in a foreground state, where the system considers it to be something the user is actively aware of and thus not a candidate for killing when low on memory. (It is still theoretically possible for the service to be killed under extreme memory pressure from the current foreground application, but in practice this should not be a concern.)
In your case, 'catching' incoming calls is best achieved with a Broadcast Receiver, registered in the manifest for intent: <action android:name="android.intent.action.PHONE_STATE" />

the answer is you dont, The OS can kill a service at anytime it needs to. you can return START_STICKY which will flag you service to be restarted when it can but there is no way to make a service run forever

Start service once and forever untill it gets killed

A simple question, how to make a Service repeat at log cat console msg "hello", as long as the Service is living/is active? I've tried:
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.v("LocalService", "Received start id " + startId + ": " + intent);
Mano lopas = new Mano(this);
lopas.Lopas();
while(true) {
Log.v("HAHA", "hello");
}
// We want this service to continue running until it is explicitly
// stopped, so return sticky.
return START_STICKY;
}
But it never returns START_STICKY, actually it doesnt even build the project. I think im missing something about services? I start my service, in MainActivity in my application, like:
startService(new Intent(getApplicationContext(),Myclass.class));
And it runs only once without my while loop in my service. It says me something in Logcat and this is it. Morever, my service starts so many times as many times I re-open my application. How to make service start run once and "forever", I mean untill it gets killed by the system or user kills it.

Services don't have their own thread, they run on the UI thread. If you want it to run in parallel, you need to create a Thread. So here you should create a Thread in your onStartCommand, and that thread should do whatever it is you want.

Same way you'd log something at intervals in your activity: use a Handler. Post a task that logs a message and re-posts itself to the same Handler using postDelayed(...). Cancel any pending execution in your activity's onPause() or your service's onDestroy().
Note that there is almost never a good reason to explicitly create a Thread or use J2SE constructs like TimerTask in Android. For heavyweight tasks, use AsyncTask. For lightweight tasks, use Handlers. In your case, creating a new Thread would be a ridiculously heavyweight solution for what you want to do.

First of all, do not forget to register the Service in your Manifest.
This can be done by using
<service android:enabled="true" android:name=".services.Paycan" />
Next is, that your Service (if its not an intentservice) run in the MainUI. If you create an endless loop make sure it's in a background thread, otherwise it will freeze the app.
You can do it using an Asynctask, a Thread which get created with onStartCommand and stopped in onDestroy or use an IntentService instead of a Service.
example:
public class yourTestClass extends Service {
Thread testThread;
boolean threadRunning = false;
#Override
public void onCreate() {
super.onCreate();
testThread = new Thread() {
#Override
public void run() {
try {
while(threadRunning) {
Thread.sleep(1000);
Log.i("test", "....");
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
threadRunning = true;
testThread.start();
return START_STICKY;
}
#Override
public void onDestroy() {
super.onDestroy();
threadRunning = false;
}