androidでbluetoothヘッドセットで音声認識＆読み上げがしたい

androidで音声認識をするために以下のようなプログラムを書いたのですが、音声認識が始まった後の文章も途中からしか認識しなかったり、文章の読み上げが途中から聞こえたりします。そのタイミングもまちまちです。
そもそもこんな方法で良いのかも含め教えていただけたら幸いです。
Bluetoothを使わない状態での音声認識、読み上げは上手くいきます。

動作は、
Bluetoothヘッドセットのボタンを押す
→ BroadcastReceiverで受け取りbluetoothHeadset.startVoiceRecognitionを行う
→ mHeadsetBroadcastReceiverでbluetoothがAUDIO_CONNECTEDを受け取り
音声認識を開始
→ 音声認識が成功したらTextToSpeechを実行
→ bluetoothHeadset.stopVoiceRecognitionでヘッドセットとの接続を終了

private SpeechRecognizer sr;
    private TextToSpeech tts;
    private String ttsString;

    private BluetoothHeadset mBluetoothHeadset;
    private boolean isBluetoothConnected;
    private BluetoothDevice bluetoothDevice;

    public static MediaButtonIntentReceiver AMButtonReciever = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
//TTS初期化
        tts = new TextToSpeech(this, this);
        tts.setOnUtteranceProgressListener(new UtteranceProgressListener() {
            @Override
            public void onDone(String utteranceId) {
               mBluetoothHeadset.stopVoiceRecognition(bluetoothDevice);
            }
            @Override
            public void onError(String utteranceId) {}
            @Override
            public void onStart(String utteranceId) {}
        });

// Bluetoothヘッドセットのボタンイベント
        if(AMButtonReciever != null){
            unregisterReceiver(AMButtonReciever);
            AMButtonReciever = null;
        }
        AMButtonReciever = new MediaButtonIntentReceiver();
        IntentFilter filter = new IntentFilter(Intent.ACTION_MEDIA_BUTTON);
        MediaButtonIntentReceiver r = new MediaButtonIntentReceiver();
        filter.setPriority(1000);
        registerReceiver(AMButtonReciever, filter);

// Bluetoothの接続状況
        registerReceiver(mHeadsetBroadcastReceiver, new IntentFilter(BluetoothHeadset.ACTION_CONNECTION_STATE_CHANGED));
        registerReceiver(mHeadsetBroadcastReceiver, new IntentFilter(BluetoothHeadset.ACTION_AUDIO_STATE_CHANGED));

        BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        bluetoothAdapter.getProfileProxy(this, mProfileListener, BluetoothProfile.HEADSET);

    }//onCreate

private BroadcastReceiver mHeadsetBroadcastReceiver = new BroadcastReceiver() {
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            int state;
            if (action.equals(BluetoothHeadset.ACTION_CONNECTION_STATE_CHANGED)) {
                state = intent.getIntExtra(BluetoothHeadset.EXTRA_STATE,
                        BluetoothHeadset.STATE_DISCONNECTED);
                if (state == BluetoothHeadset.STATE_CONNECTED) {
                } else if (state == BluetoothHeadset.STATE_DISCONNECTED) {}
            } else {
                state = intent.getIntExtra(BluetoothHeadset.EXTRA_STATE, BluetoothHeadset.STATE_AUDIO_DISCONNECTED);
                if (state == BluetoothHeadset.STATE_AUDIO_CONNECTED) {

                    try{
                        Intent intentSR = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
                        intentSR.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
                                RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
                        intentSR.putExtra(RecognizerIntent.EXTRA_PARTIAL_RESULTS, true);
                        intentSR.putExtra(RecognizerIntent.EXTRA_PROMPT, "話してください");
                        intentSR.putExtra(RecognizerIntent.EXTRA_PREFER_OFFLINE, true);

                        sr.startListening(intentSR);
                    }catch(Exception ex){
                        Toast.makeText(getApplicationContext(), "error",
                                Toast.LENGTH_LONG).show();
                    }

                } else if (state == BluetoothHeadset.STATE_AUDIO_DISCONNECTED) {
                }

            }
        }
    };

    private BluetoothProfile.ServiceListener mProfileListener = new BluetoothProfile.ServiceListener() {
        public void onServiceConnected(int profile, BluetoothProfile proxy) {
            if (profile == BluetoothProfile.HEADSET) {
                mBluetoothHeadset = (BluetoothHeadset) proxy;
                List<BluetoothDevice> devices = mBluetoothHeadset.getConnectedDevices();
                if(devices.size() > 0){
                    isBluetoothConnected = true;
                    bluetoothDevice = devices.get(0);
                }
            }
        }
        public void onServiceDisconnected(int profile) {
            if (profile == BluetoothProfile.HEADSET) {
                mBluetoothHeadset = null;
            }
        }
    };

// メディアボタンが押された時
    public class MediaButtonIntentReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            String intentAction = intent.getAction();
            if (!Intent.ACTION_MEDIA_BUTTON.equals(intentAction)) {
                return;
            }
            KeyEvent event =   (KeyEvent)intent.getParcelableExtra(Intent.EXTRA_KEY_EVENT);
            if (event == null) {
                return;
            }
            int action = event.getAction();
            if (action == KeyEvent.ACTION_DOWN) {
            if (sr == null) {
                sr = SpeechRecognizer.createSpeechRecognizer(this);
                sr.setRecognitionListener(new listener());
            }
            if (tts.isSpeaking()) {
                tts.stop();   // 読み上げ中なら止める
            }

            mBluetoothHeadset.startVoiceRecognition(bluetoothDevice);
            abortBroadcast();
        }
    }


    //  TextToSpeech
    @Override
    public void onInit(int status) {
        if (TextToSpeech.SUCCESS == status) {
            Locale locale = Locale.JAPANESE;
            if (tts.isLanguageAvailable(locale) >= TextToSpeech.LANG_AVAILABLE) {
                tts.setLanguage(locale);
            } else {
            }
        } else {
        }
    }

    private void speechText() {
        if (0 < string.length()) {
            if (tts.isSpeaking()) {
                tts.stop();// 読み上げ中なら止める
            }
            Bundle bundle = new Bundle();
            bundle.putString(TextToSpeech.Engine.KEY_PARAM_STREAM, String.valueOf(AudioManager.STREAM_VOICE_CALL));
            tts.speak(ttsString, TextToSpeech.QUEUE_FLUSH, bundle, utteranceId);
        }
    }

    // 音声認識を終了する
    protected void stopListening() {
        if (sr != null) sr.destroy();
        sr = null;
    }

    // 音声認識を再開する
    public void restartListeningService() {
        stopListening();
        startListening();
    }

    // RecognitionListenerの定義
    class listener implements RecognitionListener {
        public void onBeginningOfSpeech() {}

        public void onBufferReceived(byte[] buffer) {}

        public void onEndOfSpeech() {}

        public void onError(int error) {
            mBluetoothHeadset.stopVoiceRecognition(bluetoothDevice);
            stopListening();
        }

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

        public void onPartialResults(Bundle partialResults) {}

        public void onReadyForSpeech(Bundle params) {
            Toast.makeText(getApplicationContext(), "話してください",
                    Toast.LENGTH_SHORT).show();
        }

        public void onResults(Bundle results) {
            stopListening();
            ArrayList results_array = results.getStringArrayList(
                    SpeechRecognizer.RESULTS_RECOGNITION);
            String resultsString = "";
            for (int i = 0; i < results_array.size(); i++) {
                resultsString += results_array.get(i) + ";";
            }
            ttsString = resultsString;
            speechText();
        }
        public void onRmsChanged(float rmsdB) {}
    }