I want to make a query to Firestore database to get a url stored. Then with that url I want to show the .txt that cointains the url.
My problem is that the code executes automatically and doesn’t wait to end the query.
I want to:

1. Store the url in a variable.

2. With that variable take the .txt and read line by line in a texview.
   I can do both, but separately, when I try to do it together I have the problem, I need to wait the result and then continue executing the code. How can I do it?
   My code is:

String idioma, modo, cuento, url_cuento;
FirebaseFirestore db = FirebaseFirestore.getInstance();
@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_reproductor_cuento);

        //Hacemos llamada a clase para mostrar la pantalla completa
        PantallaCompleta pantallaCompleta = new PantallaCompleta();
        View decorView = getWindow().getDecorView();
        pantallaCompleta.pantallaCompleta(decorView);


        //Recogemos los parametros que se pasan por activities
        Bundle extra = this.getIntent().getExtras();
        idioma = extra.getString("idioma");
        modo = extra.getString("modo");
        cuento = extra.getString("cuento");

        url_cuento = consultaTxtCuento(cuento, idioma);
        new GetData().execute();
    }

public String consultaTxtCuento(String cuento, String idioma){
        final String[] urlTxt = new String[1];
        DocumentReference docRef = db.collection("cuentos").document(cuento);
        docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
            @Override
            public void onComplete(@NonNull Task<DocumentSnapshot> task) {
                if (task.isSuccessful()) {
                    DocumentSnapshot document = task.getResult();
                    if (document.exists()) {
                        urlTxt[0] = document.get("txt_" + idioma).toString();
                        System.out.println("Se obtiene como URL -> " + urlTxt[0]);
                    }
                } else {
                    Log.d(TAG, "get failed with ", task.getException());
                }
            }
        });
        return urlTxt[0];
    }

    class GetData extends AsyncTask<String, Void, String> {
        @Override
        protected String doInBackground(String... params) {
            HttpURLConnection urlConnection = null;
            String result = "";
            try {
                URL url = new URL(url_cuento);
                urlConnection = (HttpURLConnection) url.openConnection();
                int code = urlConnection.getResponseCode();
                if(code==200){
                    InputStream in = new BufferedInputStream(urlConnection.getInputStream());
                    if (in != null) {
                        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(in));
                        String line = "";
                        while ((line = bufferedReader.readLine()) != null)
                            result += line;
                    }
                    in.close();
                }
                return result;
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }

            finally {
                urlConnection.disconnect();
            }
            return result;
        }

        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);
        }
    }

What can I do to execute waiting the results? Thanks