Activity to Activity communication without finish

Issue

I have two activities: one is the main (A), and the second one which is started from A (B). I start B with startActivityForResult(intent, id).

I know I can send the result back to A via the setResult() method, but as far as I know, the result isn't sent until finish() is called. I need to send data from B to A without closing B (even several times before closing). Is there a way to achieve that?

As far as I've read, there are not many options to achieve this. I could use SharedPreferences but then I'd need also some kind of event to inform A that it has to read a value!

Any ideas appreciated.

------ FINAL SOLUTION ------

Finally I got it thanks to @Nathaniel Waggoner's advice. Here's what I did:

Inside my activity I declared the extension of BroadcastReceiver:

class ActivityBroadcast extends BroadcastReceiver {
  @Override
  public void onReceive(final Context context, final Intent intent) {
    final String txt2send = intent.getStringExtra("txt2send");
    if ((txt2send != null) && (!txt2send.isEmpty())) {
      // Do the needed stuff
      ...
    }
  }
}

So now I declared the ActivityBroadcast instance in my class and initialized it:

private static ActivityBroadcast broadcast_signal;
broadcast_signal = new ActivityBroadcast();

The way I control that it's just my Intent the one who triggers the onReceive method is with an IntentFilter set to the SENDTXT2SOCK customized action, this way:

// CustomActions.SENDJOIN2CHAN is just a constant from a customized public class
// where I define my own constants to not interfere with the "official" ones
registerReceiver(broadcast_signal, new IntentFilter(CustomActions.SENDTXT2SOCK));

This way I'm saying that on broadcast_signal will just be registered the CustomActions.SENDTXT2SOCK action, so any other is ignored. Now we just have to send a signal from the desired activity to that receiver:

final Intent intentResult = new Intent(CustomActions.SENDTXT2SOCK);
intentResult.putExtra("txt2send", "blabla");
sendBroadcast(intentResult);

And that's all, works like a charm!

Solution

Use broadcasts and intents.

Broadcast Receivers:

http://developer.android.com/reference/android/content/BroadcastReceiver.html

Answered By - Nathaniel D. Waggoner