Communication between Android Services and Activities

Question

I want to develop an Android App with three activities and two services.

The first Service, named WebClientService, calls a REST API every

Answer 1

I think your approach is ok with BroadCastReceiver. However, BroadCastReceiver should be used for a global purpose (like communicating between 2 applications). If you intend to use BroadCastReceiver for your app only, I prefer using LocalBroadcastManager instead. Using LocalBroadcastManager is faster and more security when it can be caught only by your app.

There's another way to communicate between your activitys and your services is using EventBus. It will be much easier than using BroadCastReceiver (especially in passing data between them).

Update: About your update question:

1. is it a good approach to just write my 30 seconds updates to the local db and allow the activities to update themselves every few seconds simply reading from the local db? --> Of course NO. You should let your activities update themselves when they need. When you update your local db, you should know that is there any changes or not. If there is any change, use LocalBroadcastmanager to notify your activity to update.
2. Would that affect the performance too much? --> Yes, that do. The db connection will take time to execute and it will block your UI in some cases. in that case, you should use a thread with ExecutorService for each execute (insert, update...). One more thing to consider is updating that frequently will drain your phone battery very, very fast.