REST and listviews refresh

Question

Hi,

In my app, I have different activities with listviews. The datas come from a server with a REST method, and it's only done once, when I start the application.

The pattern that I'd like to set is to precharge all the listviews with the JSONs that I already have in local, and in parallel, launch a thread that get the new JSONs files with my REST methods, and then update the listviews.

For now, when I start the app, I parse my JSONs files, and build all the lists of objects. I access them later in a static way, from my lists adapters.

So I would like to know the best way to launch this REST thread, and update the listview. Should I use AsyncTask ? A service ? and then, when I update my local JSONs, I have to re-parse them, updates the lists of object, and call in my adapters NotifyDataChanged ?

Thanks

Answer 1

So it seems that the question needs details, so I'm gonna explain what the problem is.

When I start my app, I put a splashscreen, and I parse my JSONs files in local that I saved the last time. Then I launch the app, which contains a tab activity with different listviews that use the datas that I just got from the JSONs parsing.

At the same time as I launched the app, I start an async task that querry a web service, and updates my local JSONs files. Then I parse the files again, and I'd like to notify all the listviews already launched that they have to refresh their datas. And I don't really know how to do that.

Here is the code of my async task

class UpdateTask extends AsyncTask{
    @Override
    protected Object doInBackground(Object... params) {
        // Gets all the JSON Files and save them in local
        mJsonClient.loadDistantJSON();

        // Updates the cache maps and lists
        fillsMaps();
        fillsLists(); 
        return null;
    }

    protected void onPostExecute(Object downloadReturn) {
        // Notify the listviews
            ;
    }
}

In the others activities that contains a listview, I access the cache list in local in a static way like that :

    myAdapter = new MyBaseAdapter(this,
        SplashScreen.list,listview);

I'd be glad to give more details if you want.

Thanks

Answer 2

So I found the perfect solution to my problem.
I'm using a sendBroadcast() in the onPostExecute() of my AsyncTask, with broadcastReceiver in all my activities that needed to be notified :

public class ConvenientActivity extends Activity {
    ...
    ...
    public class RefreshReceiver extends BroadcastReceiver {
        public void onReceive(Context context, Intent intent) {
            if (intent.getAction().equals(MyMainClass.REFRESH_INTENT)) {
                mAdapter.refreshList();
            }
        }
    }
}

It's pretty simple, and works perfectly.