In android a service is used to run in background. But the same can also be accomplished using alarm manager. The alarm receiver can do the same things that you would do in a service. So what is the need of service in android?
Well Both are totally different thigns.
AlarmManager Class is used to perform certain Events on after specific Time Intervalr or it can be on a regular Time Interval. An Events can be execution of Service too. AlarmManager allow you to schedule your application to be run at some point in the future.
While in case of Service it is a background process which doesnt have/requier a UI. A Service is not a saperate process or Service is not a thread. A Service is an application component representing either an application's desire to perform a longer-running operation while not interacting with the user or to supply functionality for other applications to use
Actually these are two very different things. Alarm Manager can be used to do some tasks periodically using service. But Service can be used also e.g. to move some heavy work out of the UI thread(download data from rest server) or in case of foreground services, to do some work continously (mp3 player).
You can get some explanation on how to use service (with some advices considering AlarmManager) on Styling Android.
Generally,a service is used to process logic when you don't need a UI anymore. For example the service I want to use checks a social networking site for updates every 15 minutes . The service has the logic of processing the update. But who will start the service every 15 minutes? That is where AlarmManager is used. It will periodically start my service every 15 minutes once, so that the service could execute its logic and stop itself once the job is done and my application doesn't keep draining the battery.
Related
I am designing an app that has weather info to display at home screen. I want to update weather every 10 minutes.
I have a issue to update UI when home activity is in background (another activity is open upon home activity)
some help but issue in updating UI:
Scheduling recurring task in Android
Please advice me if another way to do this. Thanks in advance.
Use AlarmManager:
Periodically executing background tasks
Executes even if application is not running
Used when long running task is not required forever
For most cases, setup a Scheduler that triggers a background service at regular intervals
Suggestion: Use IntentService in conjunction with the AlarmManager
Reference & link: AlarmManager - CodePath
I have gone through your question and I am glad to give you the appropriate answer based on my personal experience.
Well if you are interested in gathering the weather updates every 10 minutes even when the application is in background, then I suggest you to use Background Service.
You can't imagine the advantages of background service. There are three kinds of background service
Started Service
Intent Service
Bound Service
All of the above three has there own usages. But in your case i suggest you to use the Started service. This service will start when you will call the startService() method, and will stop when you will call the stopService() method. Using the background service over Alarm Manager is recommended, and implementation is also quite simple and you can go through this link to understand the background service.This service will also keep on running in background even when your app is in background and will also gather the weather data every 10 minutes.
I started learning android i've been playing with it and so far so good but i have some doubts about Services, i started learning them today so by gently if a say something very wrong.
For example, i want my app to grab some information over the internet from time to time, this polling period is defined by the user, then the UI gets updated. I though about creating a Service that run lets says every 30 minutes, gets the information and updates the UI.
If i get it right:
An IntentService just executes an operation and stops by itself sending the result through an intent(right?), so i think it's not what i want.
A Bounded Service is most likely used when you want IPC or allow binding from external apps, which again i think it's not what i want.
I think a Local Service is probably what i need, using a LocalBroadcastReceiver to update the UI, how can i make it to run the operation every X minutes( Handler postDelayed, ScheduledExecutorService or Alarm Manager ? )
If i understand it right a Service if not bounded can run infinitely if it's not killed due to low memory problems, making it a foreground Service is the safest ?
Last thing and it's kind of a noob doubt, if the user leaves the application(Click Home Button or opens other app) the app is still in background but the activities are in "Paused" or "Stopped" mode will the Service still be able to talk to them ?
Sorry for long post and thank you.
Your requirement : after every x minutes, start a service, pull some date, update UI.
Solution :
Define or set an alarm for every x minutes, to trigger a receiver.
From receiver start the service.
In the service, start an async task to fetch the data in doInBackGround().
Once data is fetched, from onPostExecute() send a broadcast to your activity.
In the activity have a dynamic receiver registered for broadcast sent from service.
From dynamic broadcast receiver update UI.
From what you've explained I wouldn't personally use a service.
The Android docs on services explain more but here is a snippet:
http://developer.android.com/guide/components/services.html
A Service is an application component that can perform long-running operations in the background and does not provide a user interface.
You could perhaps looks at using an AsyncTask, especially given that you only want it to run whilst the app is running:
http://developer.android.com/reference/android/os/AsyncTask.html
This class allows to perform background operations and publish results on the UI thread without having to manipulate threads and/or handlers.
There is a good answer here on how to run an AsyncTask repeatedly at specific time intervals: How to execute Async task repeatedly after fixed time intervals
I have two examples of Intentservice. One is the Download example in the commonsware book. the other is at http://www.vogella.com/articles/AndroidServices/article.html#servicecommunication_handler.
Both of these examples show the service executing a finite task and they both apparently destroy themselves by running to the end of the scope of the onHandleIntent event.
The service I am writing has to have events and listen for things. One is a LocationListener listening for GPS movement. Another makes Posts to a REST service and listens for replys. I want it to run until a time has elapsed or until it was told to quit by the activity that started it.
How do I keep it running? Where, for instance, do I put my implementation of LocationListener?
Thanks, Gary
How do I keep it running?
You don't. IntentService is designed to do a piece of work (or perhaps a few off a queue, if commands happen to come in rapidly), then shut down.
The service I am writing has to have events and listen for things.
Then you should not be using an IntentService. Use a regular Service, with your own background thread(s) as needed.
To keep a service running, your service need to return START_STICKY in the service method onStartCommand().
With this, the service will be running even if you exit form your activity.
Note:
The Android still kills services after some time (30 mintus to 1 hour) if they are not foreground services. Use startForeground(notification) to make it foreground.
good luck
You can achieve this in either of two ways,
AlarmManager
TimerTask
AlarmManager is android's in-buite class that allows you to execute certain action on particular time peroid.
TimerTask does same thing as AlarmManager, you can repeat certain action of your code again and again.
However AlarmManager is ligher in the execution so i suggest you to go with AlarmManager class.
Create an AlarmManager that fetches the GPS Co-ordinates and post them to server on regular interval basis.
Have a look at to this AlarmManager Example.
ok I have this application which needs to send periodic updates to a web-service, I have done a fair amount of research and I've come up with two service implementation patterns.
Implement a service with a thread, the periodic update time may vary therefore, I will put the thread to sleep with the required time-interval, then call the web-service again. I also need to update an activity, therefore will be using a broadcast receiver or a messenger.
Use a Service with a schedule timer/alarm manager, wake the system and use intent services coupled with a broadcast receiver.
Which would be the best approach?
I think I would go with the #2 option :
Create an IntentService to do the update.
Register a BroadcastReceiver with IntentFilter(s) and start the IntentService from it.
Use AlarmManager to Broadcast the registered action at the required time intervals.
I prefer this method because :
It is a very flexible pattern : You can start the service anytime by registering the same receiver for different actions like network connection changes, system boot changes etc.,
It keeps the logic loosely coupled from other parts of the app.
There is no hassle of managing threads. You get it for free by using IntentService
It is more android-ish way of solving this problem.
The main difference would be that a background service can be shut down by the user and then you won't get any more updates. If you register events with the AlarmManager, then you control when/if these events take place. If the user shuts down your app and goes into a task manager and shuts down any running services related to your app, the AlarmManager is still going to wake up and send a message that your BroadcastReceiver will receive.
I wish to do data polling(notifications) from service after a particular time interval(might be around 2-5mins). So I have written a service which will fetch data from the server. So what is the best way from performance point of view from below options.
Starting service every time when polling is to be done using Alarm manager
Or Starting service at Boot Completed using Alarm manager and keeping another Alarm Manager inside service which executes a task every particular time interval.
Thanks all..
I think the first option is better. Start IntentService with alarm manager. IntentService will receive the Intents, launch a worker thread, and stop the service as appropriate.
See: http://developer.android.com/reference/android/app/IntentService.html