Android - How to add ListView item dynamically from other class

Question

I am developing simple text messaging app using FCM (latest GCM), where I have an activity called ChatActivity that shows list of messages using ListView.

However, when any new message arrives it will be handled by FirebaseMessagingService class...

public class MyFcmListenerService extends FirebaseMessagingService {

    @override
    public void onMessageReceived(RemoteMessage remoteMessage) {

        String from = remoteMessage.getFrom();
        Map<String, String> data = remoteMessage.getData();
        String body = rawData.get("body");

        Log.i("From",from);
        Log.i("Message",body);

    }
}

This class prints message in console successfully whenever any new message arrives.

My question is, when I get a new message from FCM in onMessageReceived() class, how can I add that String message to the ListView in ChatActivity ?

And, after adding item to the ListView, how can I call .notifyDataSetChanged() on ListView Adaptor ?

Just curious. Is there any reason as to why you're not using Firebase`s real-time database for your chat app? Based from your use case, it's easier to implement. — AL., Jun 03 '16 at 02:26
On a more related note, technically, this is just like [passing data from Service to Activity](http://stackoverflow.com/questions/14351674/send-data-from-service-to-activity-android). — AL., Jun 03 '16 at 02:47

score 0 · Accepted Answer · answered Jun 04 '16 at 02:17

There are many ways you can pass data to an Activity and by extension a ListView upon receiving a message. One simple way is to set up a BroadcastReceiver in your Activity and then when you receive your FCM message you can use LocalBroadcastManager to send a broadcast indicating that your activity should update the ListView's adapter. See LocalBroadcastManager for more.

@McAwesomville suggests using Firebase Realtime Database, is also an option, you can see it in use for a simple chat app in the Firebase Android Codelab.

Thanks. LocalBroadcastManager helped to get my result. – Amit Tank Jun 06 '16 at 13:44 — Amit Tank, Jun 06 '16 at 13:44

score 0 · Answer 2 · answered Jun 06 '16 at 17:57

0

I am using FirebaseUI in my app and it works very well. You can read more about it here.

answered Jun 06 '16 at 17:57

Riley MacDonald

453
1
4
15

Android - How to add ListView item dynamically from other class

2 Answers2