Communicate with Activity from Service (LocalService) - Android Best Practices

Question

Common scenario - Activity with a background Service to poll server.

The Service will run periodically via AlarmManager and also perform tasks for the Activity (user

Answer 1

As written here

When you want to communicate from service to an Activity or Fragment which did NOT started the service or to communicate from service to multiple activities/fragments then you can use Event Bus or Broadcast Intents since they can receive callback for an event in any activity or fragment wherever they are implemented.If you want to communicate from service to an activity/fragment which started the service then you can use Pending Intent or Messenger as they can be put into an Intent extra and passed to Service.

Pending Intent

We can use createPendingResult() which creates a new PendingIntent object which you can hand to service to use and to send result data back to your activity inside onActivityResult(int, int, Intent) callback.

Event Bus

You can have the service raise events which activities or fragments can listen for and respond to using Event Bus.

Messenger

Messenger is parcelable ,and can therefore be put into an Intent extra,so your activity can pass this Messenger to the service.Service will populate Message object with whatever data needs to be send.

Broadcast Intents

Service can send a broadcast which can be responded by the activity.