CODEWITHSUNDEEP
androidandroid-activityandroid-servicealarmmanager
Sergio Serra
Sergio Serra

Reputation: 1479

Android Services and UI update

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:

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.

Upvotes: 0

Views: 1244

Answers (2)

user1923551
user1923551

Reputation: 4712

Your requirement : after every x minutes, start a service, pull some date, update UI.

Solution :

  1. Define or set an alarm for every x minutes, to trigger a receiver.
  2. From receiver start the service.
  3. In the service, start an async task to fetch the data in doInBackGround().
  4. Once data is fetched, from onPostExecute() send a broadcast to your activity.
  5. In the activity have a dynamic receiver registered for broadcast sent from service.
  6. From dynamic broadcast receiver update UI.

Upvotes: 1

Scott Helme
Scott Helme

Reputation: 4799

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

Upvotes: 0

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