Messages from Service to Client

mdsousa · Jul 13, 2020

Hi

I am creating an Activity(Client)/Service App. The Service is local and bound to the Activity. What I would like to do is send messages from the Service to the Activity. I've looked at the Messenger class and it looks promising, except the only examples I've found have the handler in the Service, where I would like the Handler in the Activity (Client) and am not sure how to reverse the examples I've found. The Client does not need to send messages to the Service. If need be, the Client will make method calls on the Service using the IBinder.

One example I've looked through is there;
https://developer.android.com/guide/components/bound-services
There are many others that do the same thing.

The plan is the Service will open comms with other processes and funnel up messages back to the Client.

Both Client and Service will be a long running process.

Any advice would be appreciated.

Edit:

I have an example of what I'd like to do
The activity example:

Java:

// Activity
public static class Binding extends Activity
{
   class IncomingHandler extends Handler   /// Handle messages from Service
    {
        @Override
        public void handleMessage(Message msg)
        {
            switch (msg.what)
            {
                case MessengerService.MSG_SET_VALUE:
                    mCallbackText.setText("Received from service: " + msg.arg1); /// MessengerService should be LocalService
                    break;
                default:
                    super.handleMessage(msg);
            }
        }
    }
   final Messenger mMessenger = new Messenger(new IncomingHandler());
  
   private LocalService mBoundService;   /// For Local Service
  
   private ServiceConnection mConnection = new ServiceConnection()
   {
        public void onServiceConnected(ComponentName className, IBinder service)
        {
  
            mBoundService = ((LocalService.LocalBinder)service).getService();  /// For Local Service

            mService = new Messenger(service);
        }
   }
   void doBindService()
   {
        bindService(new Intent(Binding.this, MessengerService.class), mConnection, Context.BIND_AUTO_CREATE);   /// MessengerService should be LocalService       
        bindService(new Intent(Binding.this, LocalService.class), mConnection, Context.BIND_AUTO_CREATE)); /// For Local Service

        mIsBound = true;
        mCallbackText.setText("Binding.");
    }
}

Example of the Service:

Java:

// Service
public class LocalService extends Service
{
   NotificationManager mNM;
   final Messenger mMessenger = new Messenger(new IncomingHandler());
  
   /// The Local Binder
   public class LocalBinder extends Binder
   {
      LocalService getService()
      {
         return LocalService.this;  /// Does this include both the ability to make local methods call and the messenger?
      }
   }

   class IncomingHandler extends Handler
   {
      @Override
      public void handleMessage(Message msg)
      {
      }
   }

   private final IBinder mBinder = new LocalBinder(); /// For Local comm with client (method calls)

   /// For the Messenger version
   @Override
   public IBinder onBind(Intent intent)
   {
     return mMessenger.getBinder();
   }
  
   /// For the Local method call version
   @Override
   public IBinder onBind(Intent intent)
   {
      return mBinder;   /// Does this include the messenger capability?
   }
}

So as you can see, I'm trying to do two things with my Service, make local method calls on it from the Activity through the IBinder and also have the Service send messages back to the Activity through a Messenger. I have to believe that this is possible, I would like to know if I'm on the right track?

Thanks...

mdsousa · Jul 20, 2020

mdsousa said:
Hi

I am creating an Activity(Client)/Service App. The Service is local and bound to the Activity. What I would like to do is send messages from the Service to the Activity. I've looked at the Messenger class and it looks promising, except the only examples I've found have the handler in the Service, where I would like the Handler in the Activity (Client) and am not sure how to reverse the examples I've found. The Client does not need to send messages to the Service. If need be, the Client will make method calls on the Service using the IBinder.

One example I've looked through is there;
https://developer.android.com/guide/components/bound-services
There are many others that do the same thing.

The plan is the Service will open comms with other processes and funnel up messages back to the Client.

Both Client and Service will be a long running process.

Any advice would be appreciated.

Edit:

I have an example of what I'd like to do
The activity example:

Java:

// Activity public static class Binding extends Activity { class IncomingHandler extends Handler /// Handle messages from Service { @Override public void handleMessage(Message msg) { switch (msg.what) { case MessengerService.MSG_SET_VALUE: mCallbackText.setText("Received from service: " + msg.arg1); /// MessengerService should be LocalService break; default: super.handleMessage(msg); } } } final Messenger mMessenger = new Messenger(new IncomingHandler()); private LocalService mBoundService; /// For Local Service private ServiceConnection mConnection = new ServiceConnection() { public void onServiceConnected(ComponentName className, IBinder service) { mBoundService = ((LocalService.LocalBinder)service).getService(); /// For Local Service mService = new Messenger(service); } } void doBindService() { bindService(new Intent(Binding.this, MessengerService.class), mConnection, Context.BIND_AUTO_CREATE); /// MessengerService should be LocalService bindService(new Intent(Binding.this, LocalService.class), mConnection, Context.BIND_AUTO_CREATE)); /// For Local Service mIsBound = true; mCallbackText.setText("Binding."); } }

Example of the Service:

Java:

// Service public class LocalService extends Service { NotificationManager mNM; final Messenger mMessenger = new Messenger(new IncomingHandler()); /// The Local Binder public class LocalBinder extends Binder { LocalService getService() { return LocalService.this; /// Does this include both the ability to make local methods call and the messenger? } } class IncomingHandler extends Handler { @Override public void handleMessage(Message msg) { } } private final IBinder mBinder = new LocalBinder(); /// For Local comm with client (method calls) /// For the Messenger version @Override public IBinder onBind(Intent intent) { return mMessenger.getBinder(); } /// For the Local method call version @Override public IBinder onBind(Intent intent) { return mBinder; /// Does this include the messenger capability? } }

So as you can see, I'm trying to do two things with my Service, make local method calls on it from the Activity through the IBinder and also have the Service send messages back to the Activity through a Messenger. I have to believe that this is possible, I would like to know if I'm on the right track?

Thanks...

Update: The IBinder method calls into the Service would be nice, but may not be necessary with the Messenger handling most of the communication, as I believe the Messenger could handle two way messaging (I'm thinking this would make it much more complicated?).

But another twist, is the Service will be communicating with a separate process through a socket (I imagine the Service would use a Thread to perform this task?) and would send what it receives through the Socket packets back up to the Client (Activity) using the messenger.

I'm curious if this what a video streamer might be like, Activity binds to a Service, which in turn connects to a video stream (through a socket), receives packets, passes them back to the Activity?

Messages from Service to Client

mdsousa

Newbie

mdsousa

Newbie