How to pause android.speech.tts.TextToSpeech?

Question

I\'m playing text with android TTS - android.speech.tts.TextToSpeech

I use: TextToSpeech.speak to speak and .stop to stop. Is

Answer 1

This solution is not perfect, but an alternative to @Aaron C's solution may be to create a custom text to speech class like the below. This solution may work well enough if your text is relatively short and spoken words per minute is accurate enough for the language you are using.

private class CustomTextToSpeech extends TextToSpeech {
    private static final double WORDS_PER_MS = (double)190/60/1000;

    long startTimestamp = 0;
    long pauseTimestamp = 0;

    private Handler handler;
    private Runnable speakRunnable;

    StringBuilder textToSpeechBuilder;

    private boolean isPaused = false;

    public CustomTextToSpeech(Context context, OnInitListener initListener){
        super(context, initListener);

        setOnUtteranceProgressListener(new UtteranceProgressListener() {
            @Override
            public void onDone(String arg0) {
                Log.d(TAG, "tts done. " + arg0);
                startTimestamp = 0;
                pauseTimestamp = 0;
                handler.postDelayed(speakRunnable, TTS_INTERVAL_MS);
            }

            @Override
            public void onError(String arg0) {
                Log.e(TAG, "tts error. " + arg0);
            }

            @Override
            public void onStart(String arg0) {
                Log.d(TAG, "tts start. " + arg0);
                setStartTimestamp(System.currentTimeMillis());
            }
        });

        handler = new Handler();

        speakRunnable = new Runnable() {
            @Override
            public void run() {
                speak();
            }
        };

        textToSpeechBuilder = new StringBuilder(getResources().getString(R.string.talkback_tips));
    }

    public void setStartTimestamp(long timestamp) {
        startTimestamp = timestamp;
    }
    public void setPauseTimestamp(long timestamp) {
        pauseTimestamp = timestamp;
    }

    public boolean isPaused(){
        return (startTimestamp > 0 && pauseTimestamp > 0);
    }

    public void resume(){
        if(handler != null && isPaused){
            if(startTimestamp > 0 && pauseTimestamp > 0){
                handler.postDelayed(speakRunnable, TTS_SETUP_TIME_MS);
            } else {
                handler.postDelayed(speakRunnable, TTS_INTERVAL_MS);
            }
        }

        isPaused = false;
    }

    public void pause(){
        isPaused = true;

        if (handler != null) {
            handler.removeCallbacks(speakRunnable);
            handler.removeMessages(1);
        }

        if(isSpeaking()){
            setPauseTimestamp(System.currentTimeMillis());
        }

        stop();
    }

    public void utter(){
        if(handler != null){
            handler.postDelayed(speakRunnable, TTS_INTERVAL_MS);
        }
    }

    public void speak(){
        Log.d(TAG, "textToSpeechBuilder: " + textToSpeechBuilder.toString());
        if(isPaused()){
            String[] words = textToSpeechBuilder.toString().split(" ");
            int wordsAlreadySpoken = (int)Math.round((pauseTimestamp - startTimestamp)*WORDS_PER_MS);
            words = Arrays.copyOfRange(words, wordsAlreadySpoken-1, words.length);

            textToSpeechBuilder = new StringBuilder();
            for(String s : words){
                textToSpeechBuilder.append(s);
                textToSpeechBuilder.append(" ");
            }
        } else {
            textToSpeechBuilder = new StringBuilder(getResources().getString(R.string.talkback_tips));
        }

        if (tts != null && languageAvailable)
            speak(textToSpeechBuilder.toString(), TextToSpeech.QUEUE_FLUSH, new Bundle(), "utter");
    }
}