Android equivalent to NSNotificationCenter

Question

In the process of porting an iPhone application over to android, I am looking for the best way to communicate within the app. Intents seem to be the way to go, is this the b

Answer 1

Here is something similar to @Shiki answer, but from the angle of iOS developers and Notification center.

First create some kind of NotificationCenter service:

public class NotificationCenter {

 public static void addObserver(Context context, NotificationType notification, BroadcastReceiver responseHandler) {
    LocalBroadcastManager.getInstance(context).registerReceiver(responseHandler, new IntentFilter(notification.name()));
 }

 public static void removeObserver(Context context, BroadcastReceiver responseHandler) {
    LocalBroadcastManager.getInstance(context).unregisterReceiver(responseHandler);
 }

 public static void postNotification(Context context, NotificationType notification, HashMap params) {
    Intent intent = new Intent(notification.name());
    // insert parameters if needed
    for(Map.Entry entry : params.entrySet()) {
        String key = entry.getKey();
        String value = entry.getValue();
        intent.putExtra(key, value);
    }
    LocalBroadcastManager.getInstance(context).sendBroadcast(intent);
 }
}

Then, you will also need some enum type to be secure of mistakes in coding with strings - (NotificationType):

public enum NotificationType {

   LoginResponse;
   // Others

}

Here is usage(add/remove observers) for example in activities:

public class LoginActivity extends AppCompatActivity{

    private BroadcastReceiver loginResponseReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
           // do what you need to do with parameters that you sent with notification

           //here is example how to get parameter "isSuccess" that is sent with notification
           Boolean result = Boolean.valueOf(intent.getStringExtra("isSuccess"));
        }
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        //subscribe to notifications listener in onCreate of activity
        NotificationCenter.addObserver(this, NotificationType.LoginResponse, loginResponseReceiver);
    }

    @Override
    protected void onDestroy() {
        // Don't forget to unsubscribe from notifications listener
        NotificationCenter.removeObserver(this, loginResponseReceiver);
        super.onDestroy();
    }
}

and here is finally how we post notification to NotificationCenter from some callback or rest service or whatever:

public void loginService(final Context context, String username, String password) {
    //do some async work, or rest call etc.
    //...

    //on response, when we want to trigger and send notification that our job is finished
    HashMap params = new HashMap();          
    params.put("isSuccess", String.valueOf(false));
    NotificationCenter.postNotification(context, NotificationType.LoginResponse, params);
}

that's it, cheers!