I have made this app that offers it's functionality almost completely in a notification. The configuration is done in the app itself. This is the structure I have now:
Service 1: retrieve data and changes to that data from FireBase and save it in an object. Everything the app needs to show in the app itself is in this object. It gets distributed to other activities via the observable pattern. So these activities implement Observer.
Service 2: this service keeps track of external changes that can directly affect the object in service 1. Therefore, this service is bound to service 1.
Activities: some activities to display the data. All these activities implement Observer and observe the object that's stored in Service 1.
So far so good. The above gives me no problems whatsoever. I can communicate with both services from every activity. Every activity gets an update if the object they are interested in changes and figures out what to do with the updated data.
Now I have this notification, all of it's actions are broadcasted intents, for which I have a BroadcastReceiver that handles these intents. The broadcastreceiver may need data from Service 1 to execute it's action, and all actions are located in simple classes (no activity or service), but I can't bind a broadcastreceiver or objects to a service.
As I see it I have 2 possible solutions here:
- Create another service in which all possible "notification" actions are located. This service can be bound to Service 1 and thus can retrieve all the data it needs.
- Make the observable object in Service 1 static, so even the objects in which the "notification" actions are located can access it.
Possible problems for solution 1: maybe 3 services is a little over-kill? But putting all functionality in the same service would create a big, unclear service.
Possible problems for solution 2: I've read that static variables are not best practice, because static variables represent global state and are hard to reason about. Source
I hope someone can tell me if I'm right on the above assumptions, and if there's a solution I have not mentioned here.