EventBus Demo

MainActivity.java

public class MainActivity extends ActionBarActivity {
    
    private EventBus eventBus;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        eventBus = EventBus.getDefault();
        
        // Register EventBus
        eventBus.register(this);
    }
    
    @Override
    protected void onDestroy() {
        super.onDestroy();
        
        // Unregister EventBus
        if (eventBus != null && eventBus.isRegistered(this)) {
            eventBus.unregister(this);
        }
    }
    
    public void buttonClicked(View v) {
        String text = ((EditText)v).getText().toString();
        if (!text.isEmpty()) {
            eventBus.post(new MessageEvent(text));
        }
    }
    
    /* subscriber method */
    public void onEvent(ResponderService.ServiceMessageEvent event) {
        String data = event.getMessage();
        // do something with this message
    }
    
    public class MessageEvent {
        private String message;

        public MessageEvent(String text) {
            message = text;
        }

        public String getMessage() {
            return message;
        }

        public void setMessage(String msg) { message = msg;}
    }
}

ResponderService.java

public class ResponderService extends Service {
    @Override
    public IBinder onBind(Intent intent) {return null;}

    @Override
    public void onCreate() {}
    
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        // Register EventBus
        if (!EventBus.getDefault().isRegistered(this)) {
            EventBus.getDefault().register(this);
        }
        return START_STICKY;
    }
    
    public void onEvent(MessageEvent event) {
        String message = event.getMessage();
        // process data
        String processed_message = new StringBuilder(event.getMessage()).reverse().toString();
        // post : send to activity
        EventBus.getDefault().post(new ServiceMessageEvent(processed_message));
    }
    
    @Override
    public void onDestroy() {
        super.onDestroy();
        // unregister EventBus
        EventBus.getDefault().unregister(this);
    }
    
    public class ServiceMessageEvent {
        private String message;

        public ServiceMessageEvent(String text) {
            message = text;
        }

        public String getMessage() {
            return message;
        }

        public void setMessage(String msg) { message = msg;}
    }
}