[android-developers] How do I call a service, to retrieve data, from a content provider?

I'm trying to implement a pattern of accessing data source, independently if it's local or remote, using a content provider.

So, inside the content provider, for example in the query method:

public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {...}

I want to, check if data is stored locally, if not, then call the webservice, on response save and return it. Typical request process with a local cache.

Now to get the data from the webservice, I wanted to use a service. Because I want that once started, it will receive and process the response, even if the user exits the app / the system kills it, etc. 

Note: I don't need to use anything synchronous here, since I'm already running the query to the content provider asynchronouly (AsyncQueryHandler). So I think I have to use Service instead of e.g. IntentService.

The idea with the service is to have a method to call the webservice:

public WebserviceResponse callWebservice(params) {...}

And in ContentProvider.query(): 

WebserviceResponse response = myService.callWebservice(params);

But the problem is that I can't find how to ensure that the service is already bound before the first query. If I bind it in ContentProvider.onCreate:

@Override

public boolean onCreate() {

    final Context context = getContext();

    dbHelper = new DatabaseHelper(context);

    context.bindService(new Intent(context, MyService.class), mConnection, Context.BIND_AUTO_CREATE);

    return true;

}

Where mConnection is:

private ServiceConnection mConnection = new ServiceConnection() {

   public void onServiceConnected(ComponentName className, IBinder binder) {

        myService = ((MyService.MyBinder) binder).getService();

   }

   public void onServiceDisconnected(ComponentName className) {

        myService = null;

    }

};

And I do a query using this content provider in my activity's onCreate(), the service is not bound yet and I get an exception when I try to use it.

A way around I can think of, is to call the webservice directly - without a service - from the content provider. This will be synchronous and I can process the response without problems there. But it has mentioned disadvantage that the call can be interrupted and the data not processed. It's not the end of the world - the next time the user opens the app, the webservice would be called again. But I still would like to not have it that way.

A second possibility I can think of, is to invert this logic and do the access to the content provider in a (asynchronous) service. But here I have a different problem, which is that, afair, the async service (IntentService) communicates with the caller though with IPC and this is not supposed to pass large amounts of data. So I would have again to wrap this in some other logic which after service is finished checks a flag and retrieves data, this time directly from the content provider. This would also mean to start a second async query.

I already came up with an architecture that works, but it's quite complex. It:

1. Does async query to the content provider

2. If there's no data, starts an IntentService to get it from remote.

3. After the service finishes it returns a flag, and then, does again async query to get the data which was saved by the webservice.

I would like to simplify it, that's why I'm asking this. 

So is there any way that I can use the service in the content provider, or any other approach, or advice you would recommend?

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