Android TextToSpeech（TTS）庫本身并不提供語音識別功能。但是，您可以結合使用Android的語音識別服務來實現這個需求。以下是實現語音識別的步驟：

1. 添加權限：在AndroidManifest.xml文件中添加以下權限：

<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.INTERNET" />

2. 檢查權限：在運行時檢查用戶是否已授予這些權限。如果尚未授權，請請求用戶授權。

private static final int REQUEST_RECORD_AUDIO_PERMISSION = 200;

private void requestRecordAudioPermission() {
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.RECORD_AUDIO)
            != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this,
                new String[]{Manifest.permission.RECORD_AUDIO},
                REQUEST_RECORD_AUDIO_PERMISSION);
    } else {
        startRecording();
    }
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    if (requestCode == REQUEST_RECORD_AUDIO_PERMISSION) {
        if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            startRecording();
        } else {
            Toast.makeText(this, "Permission denied. Could not record audio.", Toast.LENGTH_SHORT).show();
        }
    }
}

3. 開始錄音：使用MediaRecorder類開始錄音。

private void startRecording() {
    MediaRecorder mediaRecorder = new MediaRecorder();
    mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
    mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
    mediaRecorder.setOutputFile("/sdcard/audio.3gp");

    try {
        mediaRecorder.prepare();
        mediaRecorder.start();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

4. 停止錄音：在適當的時候停止錄音，例如在用戶按下停止按鈕時。

private void stopRecording() {
    if (mediaRecorder != null) {
        mediaRecorder.stop();
        mediaRecorder.release();
        mediaRecorder = null;
    }
}

5. 使用語音識別器：創建一個SpeechRecognizer實例并使用它來識別用戶的語音。

private SpeechRecognizer speechRecognizer;
private Intent speechRecognizerIntent;

private void initSpeechRecognizer() {
    speechRecognizer = SpeechRecognizer.createSpeechRecognizer(this);
    speechRecognizerIntent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
    speechRecognizerIntent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL, RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
    speechRecognizerIntent.putExtra(RecognizerIntent.EXTRA_LANGUAGE, "en-US");
    speechRecognizerIntent.putExtra(RecognizerIntent.EXTRA_PARTIAL_RESULTS, true);
}

6. 開始識別：開始語音識別并處理結果。

private void startVoiceRecognition() {
    speechRecognizer.startListening(speechRecognizerIntent);
}

private void stopVoiceRecognition() {
    if (speechRecognizer != null) {
        speechRecognizer.stopListening();
    }
}

@Override
public void onResults(Bundle results) {
    ArrayList<String> matches = results.getStringArrayList(SpeechRecognizer.RESULTS_RECOGNITION);
    if (matches != null && !matches.isEmpty()) {
        String recognizedText = matches.get(0);
        // 處理識別到的文本
    }
}

7. 釋放資源：在不再需要語音識別器時，釋放相關資源。

private void releaseSpeechRecognizer() {
    if (speechRecognizer != null) {
        speechRecognizer.destroy();
        speechRecognizer = null;
    }
}

現在，您可以結合使用TextToSpeech和語音識別器來實現所需的功能。例如，您可以在用戶說出某些關鍵詞時觸發語音識別，并根據識別到的內容執行相應操作。