Voice Recognition as a background service

Is it possible to implement an activity as a service? My activity is a voice recognition activity. I want to have the activity running in the background of the app constantly checking for voice and when the user says a command it will recognize it and then perform the action. My question is...is it possible to do this and if so how can the background service notify the current activity or application? There was a previous post on this which had no clear answer...Thanks for any input or help. Here is the voice activity...taken from another StackOverflow post:

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.speech.RecognitionListener;
import android.speech.RecognizerIntent;
import android.speech.SpeechRecognizer;
import android.widget.Button;
import android.widget.TextView;
import java.util.ArrayList;
import android.util.Log;



public class voiceRecognitionTest extends Activity implements OnClickListener 
{

   private TextView mText;
   private SpeechRecognizer sr;
   private static final String TAG = "MyStt3Activity";
   @Override
   public void onCreate(Bundle savedInstanceState) 
   {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
            Button speakButton = (Button) findViewById(R.id.btn_speak);     
            mText = (TextView) findViewById(R.id.textView1);     
            speakButton.setOnClickListener(this);
            sr = SpeechRec开发者_开发百科ognizer.createSpeechRecognizer(this);       
            sr.setRecognitionListener(new listener());        
   }

   class listener implements RecognitionListener          
   {
            public void onReadyForSpeech(Bundle params)
            {
                     Log.d(TAG, "onReadyForSpeech");
            }
            public void onBeginningOfSpeech()
            {
                     Log.d(TAG, "onBeginningOfSpeech");
            }
            public void onRmsChanged(float rmsdB)
            {
                     Log.d(TAG, "onRmsChanged");
            }
            public void onBufferReceived(byte[] buffer)
            {
                     Log.d(TAG, "onBufferReceived");
            }
            public void onEndOfSpeech()
            {
                     Log.d(TAG, "onEndofSpeech");
            }
            public void onError(int error)
            {
                     Log.d(TAG,  "error " +  error);
                     mText.setText("error " + error);
            }
            public void onResults(Bundle results)                   
            {
                     String str = new String();
                     Log.d(TAG, "onResults " + results);
                     ArrayList data = results.getStringArrayList(SpeechRecognizer.RESULTS_RECOGNITION);
                     for (int i = 0; i < data.size(); i++)
                     {
                               Log.d(TAG, "result " + data.get(i));
                               str += data.get(i);
                     }
                     mText.setText("results: "+String.valueOf(data.size()));        
            }
            public void onPartialResults(Bundle partialResults)
            {
                     Log.d(TAG, "onPartialResults");
            }
            public void onEvent(int eventType, Bundle params)
            {
                     Log.d(TAG, "onEvent " + eventType);
            }
   }
   public void onClick(View v) {
            if (v.getId() == R.id.btn_speak) 
            {
                Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);        
                intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
                intent.putExtra(RecognizerIntent.EXTRA_CALLING_PACKAGE,"voice.recognition.test");

                intent.putExtra(RecognizerIntent.EXTRA_MAX_RESULTS,5); 
                     sr.startListening(intent);
                     Log.i("111111","11111111");
            }
   }
}

---

What you can do is launch the recognizer activity which will listen for commands and when it finds an appropriate command it will do whatever you want it to do on that particular command. The problem with this simple approach is that the activity will constantly be listening for speech input and more importantly IT NEEDS TO BE IN FOCUS and not running in background...

http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/app/VoiceRecognition.html