Android Speech Recognition Continuous Service

Question

I'm trying to create a service to run continuous speech recognition in Android 4.2. Using the answer from this link ( Android Speech Recognition as a service on Android 4.1 & 4.2 ), I created a service that is run from an Activity. My problem is that I get null exceptions when accessing mTarget.mAudioManager or mTarget.mSpeechRecognizerIntent in the handleMessage method. The target (and mTarget object created from it) is not null, but all the objects inside it are.

What am I doing wrong here?

Relevant Activity Code (static methods called from activity, activityContext is the activity this method is called from):

public static void init(Context context)
{
   voiceCommandService = new VoiceCommandService();
   activityContext = context;
}

public static void startContinuousListening()
{
    Intent service = new Intent(activityContext, VoiceCommandService.class);
    activityContext.startService(service);

    Message msg = new Message();
    msg.what = VoiceCommandService.MSG_RECOGNIZER_START_LISTENING; 

    try
    {
      voiceCommandService.mServerMessenger.send(msg);
    } 
    catch (RemoteException e)
   {
    e.printStackTrace();
   }

}

Service Code:

public class VoiceCommandService extends Service
{
protected AudioManager mAudioManager; 
protected SpeechRecognizer mSpeechRecognizer;
protected Intent mSpeechRecognizerIntent;
protected final Messenger mServerMessenger = new Messenger(new IncomingHandler(this));

protected boolean mIsListening;
protected volatile boolean mIsCountDownOn;

static final int MSG_RECOGNIZER_START_LISTENING = 1;
static final int MSG_RECOGNIZER_CANCEL = 2;

@Override
public void onCreate()
{
    super.onCreate();
    mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE); 
    mSpeechRecognizer = SpeechRecognizer.createSpeechRecognizer(this);
    mSpeechRecognizer.setRecognitionListener(new SpeechRecognitionListener());
    mSpeechRecognizerIntent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
    mSpeechRecognizerIntent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
                                     RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
    mSpeechRecognizerIntent.putExtra(RecognizerIntent.EXTRA_CALLING_PACKAGE,
                                     this.getPackageName());
}

protected static class IncomingHandler extends Handler
{
    private WeakReference<VoiceCommandService> mtarget;

    IncomingHandler(VoiceCommandService target)
    {
        mtarget = new WeakReference<VoiceCommandService>(target);
    }


    @Override
    public void handleMessage(Message msg)
    {
        final VoiceCommandService target = mtarget.get();

        switch (msg.what)
        {
            case MSG_RECOGNIZER_START_LISTENING:

                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN)
                {
                    // turn off beep sound  
                    target.mAudioManager.setStreamMute(AudioManager.STREAM_SYSTEM, true);
                }
                 if (!target.mIsListening)
                 {
                     target.mSpeechRecognizer.startListening(target.mSpeechRecognizerIntent);
                     target.mIsListening = true;
                    //Log.d(TAG, "message start listening"); //$NON-NLS-1$
                 }
                 break;

             case MSG_RECOGNIZER_CANCEL:
                  target.mSpeechRecognizer.cancel();
                  target.mIsListening = false;
                  //Log.d(TAG, "message canceled recognizer"); //$NON-NLS-1$
                  break;
         }
   } 
} 

// Count down timer for Jelly Bean work around
protected CountDownTimer mNoSpeechCountDown = new CountDownTimer(5000, 5000)
{

    @Override
    public void onTick(long millisUntilFinished)
    {
        // TODO Auto-generated method stub

    }

    @Override
    public void onFinish()
    {
        mIsCountDownOn = false;
        Message message = Message.obtain(null, MSG_RECOGNIZER_CANCEL);
        try
        {
            mServerMessenger.send(message);
            message = Message.obtain(null, MSG_RECOGNIZER_START_LISTENING);
            mServerMessenger.send(message);
        }
        catch (RemoteException e)
        {

        }
    }
};

@Override
public void onDestroy()
{
    super.onDestroy();

    if (mIsCountDownOn)
    {
        mNoSpeechCountDown.cancel();
    }
    if (mSpeechRecognizer != null)
    {
        mSpeechRecognizer.destroy();
    }
}

protected class SpeechRecognitionListener implements RecognitionListener
{

    private static final String TAG = "SpeechRecognitionListener";

    @Override
    public void onBeginningOfSpeech()
    {
        // speech input will be processed, so there is no need for count down anymore
        if (mIsCountDownOn)
        {
            mIsCountDownOn = false;
            mNoSpeechCountDown.cancel();
        }               
        //Log.d(TAG, "onBeginingOfSpeech"); //$NON-NLS-1$
    }

    @Override
    public void onBufferReceived(byte[] buffer)
    {

    }

    @Override
    public void onEndOfSpeech()
    {
        //Log.d(TAG, "onEndOfSpeech"); //$NON-NLS-1$
     }

    @Override
    public void onError(int error)
    {
        if (mIsCountDownOn)
        {
            mIsCountDownOn = false;
            mNoSpeechCountDown.cancel();
        }
         mIsListening = false;
         Message message = Message.obtain(null, MSG_RECOGNIZER_START_LISTENING);
         try
         {
                mServerMessenger.send(message);
         }
         catch (RemoteException e)
         {

         }
        //Log.d(TAG, "error = " + error); //$NON-NLS-1$
    }

    @Override
    public void onEvent(int eventType, Bundle params)
    {

    }

    @Override
    public void onPartialResults(Bundle partialResults)
    {

    }

    @Override
    public void onReadyForSpeech(Bundle params)
    {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN)
        {
            mIsCountDownOn = true;
            mNoSpeechCountDown.start();
            mAudioManager.setStreamMute(AudioManager.STREAM_SYSTEM, false);
        }
        Log.d(TAG, "onReadyForSpeech"); //$NON-NLS-1$
    }

    @Override
    public void onResults(Bundle results)
    {
        //Log.d(TAG, "onResults"); //$NON-NLS-1$

    }

    @Override
    public void onRmsChanged(float rmsdB)
    {

    }

}

@Override
public IBinder onBind(Intent arg0) {
    // TODO Auto-generated method stub
    return null;
}
}

Yes it is. I just posted the init code that initializes the activityContext and service as well. I tried running the code in the static methods from the Activity itself (non-static methods) with the same results. — rmooney, Aug 05 '13 at 02:49
How do you define voiceCommandService in voiceCommandService.mServerMessenger.send(msg);? This look wrong and this is probably why your code does not work. — Hoan Nguyen, Aug 05 '13 at 02:58
VoiceCommandService voiceCommandService = null; I just defined it as an instance of the service class and I instantiate it that way. How should it be done instead? — rmooney, Aug 05 '13 at 03:03
From the "docs": The implementation of this API is likely to stream audio to remote servers to perform speech recognition. As such this API is not intended to be used for continuous recognition, which would consume a significant amount of battery and bandwidth. - I am just saying this because you are going against the stream here. ( I am trying the same... :) — Glenn Bech, Aug 08 '14 at 21:44
@rmooney am following this guide to create an android speech recognition service and am running into the same problem as you with null exceptions. can you please tell me how you resolved this issue? — aditya, Oct 12 '14 at 04:49
I have implemented continuous speech recognition in the background with notification. Working example is on https://github.com/Anshul1507/Foreground-SpeechRecognition — Anshul1507, Nov 05 '21 at 08:27
For anyone reading this, the comment by @Anshul1507 has an up to date (2021) Kotlin implementation of this. Thanks for bringing life to a very old question. — rmooney, Nov 05 '21 at 18:08

score 17 · Accepted Answer · edited Nov 16 '16 at 13:47

17

Class members in MainActivity

private int mBindFlag;
private Messenger mServiceMessenger;

Start service in onCreate()

@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);

    Intent service = new Intent(activityContext, VoiceCommandService.class);
    activityContext.startService(service);
    mBindFlag = Build.VERSION.SDK_INT < Build.VERSION_CODES.ICE_CREAM_SANDWICH ? 0 : Context.BIND_ABOVE_CLIENT;

}

Bind service in onStart()

@Override
protected void onStart()
{
    super.onStart();

    bindService(new Intent(this, VoiceCommandService.class), mServiceConnection, mBindFlag);
}

@Override
protected void onStop()
{
    super.onStop();

    if (mServiceMessenger != null)
    {
        unbindService(mServiceConnection);
        mServiceMessenger = null;
    }
}

mServiceConnection member

private final ServiceConnection mServiceConnection = new ServiceConnection()
{
    @Override
    public void onServiceConnected(ComponentName name, IBinder service)
    {
        if (DEBUG) {Log.d(TAG, "onServiceConnected");} //$NON-NLS-1$

        mServiceMessenger = new Messenger(service);
        Message msg = new Message();
        msg.what = VoiceCommandService.MSG_RECOGNIZER_START_LISTENING; 

        try
        {
            mServiceMessenger.send(msg);
        } 
        catch (RemoteException e)
        {
            e.printStackTrace();
        }
    }

    @Override
    public void onServiceDisconnected(ComponentName name)
    {
        if (DEBUG) {Log.d(TAG, "onServiceDisconnected");} //$NON-NLS-1$
        mServiceMessenger = null;
    }

}; // mServiceConnection

In the service

@Override
public IBinder onBind(Intent intent)
{
    Log.d(TAG, "onBind");  //$NON-NLS-1$

    return mServerMessenger.getBinder();
}

edited Nov 16 '16 at 13:47

UVM

9,776
6
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answered Aug 05 '13 at 03:22

Hoan Nguyen

18,033
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This made it work. I guess I just needed the service connection to be set up properly in this activity. Thank you so much for your help! – rmooney Aug 05 '13 at 12:55
2

Your service works fine also on Android 4.4. Now I want to restart speech recognition after onResult() is called. I already tried to send a MSG_RECOGNIZER_START_LISTENING Message again or call mSpeechRecognizer.startListening but it does not work and I don't know why. I get no exception. How can force the SpeechRecognizer to restart after onResult is called immediately? – roschulze Jan 04 '14 at 17:17
I do not have any device with 4.4, so I cannot test it. But try to send a MSG_RECOGNIZER_CANCEL and then MSG_RECOGNIZER_START_LISTENING to see if this would work. – Hoan Nguyen Jan 04 '14 at 17:56
I'm having the same problem on my Galaxy Note 3 running 4.3. – MacKinley Smith Jan 25 '14 at 19:38
Again I do not have 4.3 or later. The worst thing you have to do is to call destroy(), create(), setRecognitionListener() and then send a listening message again in onResult(). – Hoan Nguyen Jan 25 '14 at 20:56
Neither onPartialResults or onResults is getting called! No exceptions as well. @rmooney , could you post the complete working code for this? – Anand Sainath Mar 17 '14 at 23:58
Did onReadyForSpeech get called? – Hoan Nguyen Mar 18 '14 at 00:01
What if I don't want to bind it? – Rony Tesler Sep 09 '14 at 14:45
Then you have to find some other way to send message to the service. – Hoan Nguyen Sep 09 '14 at 19:40
2

Is your approach towards continuous speech recognition battery efficient? – Josh Feb 27 '15 at 15:33
2

No the battery life is cut in half. – Hoan Nguyen Feb 27 '15 at 23:06
@HoanNguyen - don't you get gaps of no listening between the end of one process (upon onError or onResults) to "onReadyForSpeech" (cause it is usually ready about ~200 miliseconds after startListening was called)? – Ronen Rabinovici May 17 '15 at 00:28
I did not notice it since in my app, I sent a message for the UI to turn the microphone to green when onReadyForSpeech is called. So I have no problem at all because users do not speak until the microphone turn green. – Hoan Nguyen May 17 '15 at 04:55
1

@HoanNguyen do you have full working code in the github? – A J Jun 20 '15 at 08:05
awesome saved my day. best solution. – Sabari Karthik Jan 19 '18 at 10:17

Sachin Varma · Answer 2 · 2018-04-18T10:42:14.950

Working example is given below,

MyService.class

public class MyService extends Service implements SpeechDelegate, Speech.stopDueToDelay {

  public static SpeechDelegate delegate;

  @Override
  public int onStartCommand(Intent intent, int flags, int startId) {
    //TODO do something useful
    try {
      if (VERSION.SDK_INT >= VERSION_CODES.KITKAT) {
        ((AudioManager) Objects.requireNonNull(
          getSystemService(Context.AUDIO_SERVICE))).setStreamMute(AudioManager.STREAM_SYSTEM, true);
      }
    } catch (Exception e) {
      e.printStackTrace();
    }

    Speech.init(this);
    delegate = this;
    Speech.getInstance().setListener(this);

    if (Speech.getInstance().isListening()) {
      Speech.getInstance().stopListening();
    } else {
      System.setProperty("rx.unsafe-disable", "True");
      RxPermissions.getInstance(this).request(permission.RECORD_AUDIO).subscribe(granted -> {
        if (granted) { // Always true pre-M
          try {
            Speech.getInstance().stopTextToSpeech();
            Speech.getInstance().startListening(null, this);
          } catch (SpeechRecognitionNotAvailable exc) {
            //showSpeechNotSupportedDialog();

          } catch (GoogleVoiceTypingDisabledException exc) {
            //showEnableGoogleVoiceTyping();
          }
        } else {
          Toast.makeText(this, R.string.permission_required, Toast.LENGTH_LONG).show();
        }
      });
    }
    return Service.START_STICKY;
  }

  @Override
  public IBinder onBind(Intent intent) {
    //TODO for communication return IBinder implementation
    return null;
  }

  @Override
  public void onStartOfSpeech() {
  }

  @Override
  public void onSpeechRmsChanged(float value) {

  }

  @Override
  public void onSpeechPartialResults(List<String> results) {
    for (String partial : results) {
      Log.d("Result", partial+"");
    }
  }

  @Override
  public void onSpeechResult(String result) {
    Log.d("Result", result+"");
    if (!TextUtils.isEmpty(result)) {
      Toast.makeText(this, result, Toast.LENGTH_SHORT).show();
    }
  }

  @Override
  public void onSpecifiedCommandPronounced(String event) {
    try {
      if (VERSION.SDK_INT >= VERSION_CODES.KITKAT) {
        ((AudioManager) Objects.requireNonNull(
          getSystemService(Context.AUDIO_SERVICE))).setStreamMute(AudioManager.STREAM_SYSTEM, true);
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
    if (Speech.getInstance().isListening()) {
      Speech.getInstance().stopListening();
    } else {
      RxPermissions.getInstance(this).request(permission.RECORD_AUDIO).subscribe(granted -> {
        if (granted) { // Always true pre-M
          try {
            Speech.getInstance().stopTextToSpeech();
            Speech.getInstance().startListening(null, this);
          } catch (SpeechRecognitionNotAvailable exc) {
            //showSpeechNotSupportedDialog();

          } catch (GoogleVoiceTypingDisabledException exc) {
            //showEnableGoogleVoiceTyping();
          }
        } else {
          Toast.makeText(this, R.string.permission_required, Toast.LENGTH_LONG).show();
        }
      });
    }
  }


  @Override
  public void onTaskRemoved(Intent rootIntent) {
    //Restarting the service if it is removed.
    PendingIntent service =
      PendingIntent.getService(getApplicationContext(), new Random().nextInt(),
        new Intent(getApplicationContext(), MyService.class), PendingIntent.FLAG_ONE_SHOT);

    AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
    assert alarmManager != null;
    alarmManager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, 1000, service);
    super.onTaskRemoved(rootIntent);
  }
}

For more details,

https://github.com/sachinvarma/Speech-Recognizer

Hope this will help someone in future.

In android 8.0 I have that beep sound always when starting the recorder. Any way to remove it? I tried volume to 0 but not worked at all... — lacas, Oct 14 '18 at 11:17
Thanks. Also this is very battery killer. Any new way to do this continuesly? — lacas, Oct 14 '18 at 11:24
How to run the app from this github repo? I have a lot of errors. — user12628549, Jun 26 '21 at 15:12

Android Speech Recognition Continuous Service

2 Answers2

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