Binding Service - Service

ObverserPtnService.java

 /** 
 * Command to the service to register a client, receiving callbacks 
 * from the service.  The Message's replyTo field must be a Messenger of 
 * the client where callbacks should be sent. 
 */ 
public final static int MSG_REGISTER_CLIENT = 1;
/** 
 * Command to the service to unregister a client, ot stop receiving callbacks 
 * from the service.  The Message's replyTo field must be a Messenger of 
 * the client as previously given with MSG_REGISTER_CLIENT. 
 */ 
public final static int MSG_UNREGISTER_CLIENT = 2;
/** 
 * Command to service to set a new value.  This can be sent to the 
 * service to supply a new value, and will be sent by the service to 
 * any registered clients with the new value. 
 */ 
static final int MSG_SET_VALUE = 3;

ArrayList<Messenger> mClients = new ArrayList<Messenger>(); 

private final Messenger mMessenger = new Messenger(new IncomingHandler());

private class IncomingHandler extends Handler {
    @Override 
    public void handleMessage(Message msg) {
        switch (msg.what) { 
        case MSG_REGISTER_CLIENT: 
            mClients.add(msg.replyTo); 
            break; 
        case MSG_UNREGISTER_CLIENT: 
            mClients.remove(msg.replyTo); 
            break; 
        } 
    } 
} 

@Override 
public IBinder onBind(Intent intent) { 
    return mMessenger.getBinder(); 
} 

/** 
 * Send Message to Clients. 
 * @param msg Message 
 */ 
private void sendMessageToClients(Message msg) {
    for (int i = mClients.size() - 1; i >= 0; i--) { 
        try { 
            // send a message to mClients. 
            // you may have handle this massage from IncomingHandler at any Activity
            mClients.get(i).send(msg); 
        } catch (RemoteException e) { 
            // The client is dead. Remove it from the list; 
            // we are going through the list from back to front
            // so this is safe to do inside the loop. 
            mClients.remove(i); 
        } 
    } 
}