PingPong_SpeechRecognizer.java

...
  
private void initSpeechRecognizer() {
  
  // Create the speech recognizer and set the listener
  speechRecognizer = SpeechRecognizer.createSpeechRecognizer(context);
  speechRecognizer.setRecognitionListener(recognitionListener); 

  // Create the intent with ACTION_RECOGNIZE_SPEECH 
  speechIntent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
  speechIntent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL, RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
  speechIntent.putExtra(RecognizerIntent.EXTRA_LANGUAGE, Locale.US);
   
  listen();
}

...

public void listen() {

    // startListening should be called on Main thread
    Handler mainHandler = new Handler(Looper.getMainLooper());
    Runnable myRunnable = () -> speechRecognizer.startListening(speechIntent);
    mainHandler.post(myRunnable);
}

...

RecognitionListener recognitionListener = new RecognitionListener() {
        
  ...

  @Override
  public void onError(int errorCode) { 

      // ERROR_NO_MATCH states that we didn't get any valid input from the user
      // ERROR_SPEECH_TIMEOUT is invoked after getting many ERROR_NO_MATCH 
      // In these cases, let's restart listening.
      // It is not recommended by Google to listen continuously user input, obviously it drains the battery as well,
      // but for now let's ignore this warning
      if ((errorCode == SpeechRecognizer.ERROR_NO_MATCH) || (errorCode == SpeechRecognizer.ERROR_SPEECH_TIMEOUT)) {

          listen();
      }
  }

  @Override
  public void onResults(Bundle bundle) {

      // it returns 5 results as default.
      ArrayList<String> results = bundle.getStringArrayList(SpeechRecognizer.RESULTS_RECOGNITION);
      
      // a method that finds the best matched player, and updates the view. 
      findBestMatchPlayer(results);
  }

  ...
};