RecogniseListener在onReadyForSpeech处停止

Question

当持续通话时，RecogniseListener工作正常，但每当有5-10秒的静音时，会调用监听器的onReadyForSpeech（）方法，但永远不会调用onBegginingOfSpeech（）。

这是我的听众：

    sr = SpeechRecognizer.createSpeechRecognizer(this);
    sr.setRecognitionListener(new RecognitionListener() {
        @Override
        public void onReadyForSpeech(Bundle params) {
        }
        @Override
        public void onBeginningOfSpeech() {
        }

        @Override
        public void onRmsChanged(float rmsdB) {
        }

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

        @Override
        public void onEndOfSpeech() {
            startRecognising();
        }


        @Override
        public void onError(int error) {
        }

        @Override
        public void onResults(Bundle results) {
            adapter.add(new MessageData(MessageData.TYPE_VOICE,  recognisedText.getText().toString()), 0);
            recyclerView.scrollToPosition(0);
            recognisedText.setText("");
        }

        @Override
        public void onPartialResults(Bundle partialResults) {
            ArrayList data = partialResults.getStringArrayList(SpeechRecognizer.RESULTS_RECOGNITION);
            String word = (String) data.get(data.size() - 1);
            recognisedText.setText(word);
        }

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

startRecognising（）方法：

private void startRecognising(){
    Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
    intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
    intent.putExtra(RecognizerIntent.EXTRA_SPEECH_INPUT_MINIMUM_LENGTH_MILLIS, 20000000);
    intent.putExtra(RecognizerIntent.EXTRA_CALLING_PACKAGE,"voice.recognition.test");
    intent.putExtra(RecognizerIntent.EXTRA_PARTIAL_RESULTS, true);

    intent.putExtra(RecognizerIntent.EXTRA_MAX_RESULTS,1);
    sr.startListening(intent);
}

顺便说一下，有没有可以实时识别语音的免费替代方案？