How to run RecognitionListener at the background of the app?

everyone! I am developing an application for voice recognition, and the application is able to recognize the speech right now! However, I need to run this voice recognition code at the background of the app, it has to listen to the commands all the time. For my app, I wrote Handler().postDelayed function, it calculates the time when the user lands a new activity and it starts listening by delaying for 5 seconds. My problem is that it just listens 2-3 seconds, and it is not able to recognize and listen again. How can I run voice recognition at the background of the app when the app is running?

speechRecognizer1.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() {

        }

        @Override
        public void onError(int error) {

        }

        @Override
        public void onResults(Bundle bundle) {
            ArrayList<String> matches1 =bundle.getStringArrayList(speechRecognizer1.RESULTS_RECOGNITION);
            String string="";
            if(matches1!=null) {
                string = matches1.get(0);
                textView3.setText(string);
                Speak();

            }
        }



        @Override
        public void onPartialResults(Bundle bundle) {


        }

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

        }
    });

    mTTS1 = new TextToSpeech(this, new TextToSpeech.OnInitListener() {
        @Override
        public void onInit(int status) {
            if(status==TextToSpeech.SUCCESS){
                int result= mTTS1.setLanguage(Locale.ENGLISH);
                if(result== TextToSpeech.LANG_MISSING_DATA || result==TextToSpeech.LANG_NOT_SUPPORTED){
                    Log.e("TTS","Language Not Supported");

                }



            }
        }
    });

    new Handler().postDelayed(new Runnable(){
        public void run(){
            speechRecognizer1.startListening(intentRecognizer1);
        }
    }, 5000);

Ok for this you need an android component called Service we have three types of services in android :

1. Forground: a foreground service do works that is noticeable to the user for example a music app with a notification about the song that is playing.
2. Background: this service is not noticeable to the user
3. Bound: and bound service which offers the user a client-server interaction

for your case you can use a foreground service. to decide what is better and how to implement it or deciding between a thread and a service I recommend reading this document : https://developer.android.com/guide/components/services