Android - Colocar un dato en tiempo real de firebase en un fragment de android studio

package com.iotpanama.sensorgasdestection.ui.sensores;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.ArrayAdapter;

import android.widget.Spinner;

import android.widget.TextView;

import androidx.annotation.Nullable;

import androidx.annotation.NonNull;

import androidx.fragment.app.Fragment;

import androidx.lifecycle.Observer;

import androidx.lifecycle.ViewModelProviders;

import com.iotpanama.sensorgasdestection.R;

public class sensorFragment extends Fragment {

  private sensorViewModel sensorViewModel;

  public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    //sensorViewModel = ViewModelProviders.of(this).get(sensorViewModel.class);

    View root = inflater.inflate(R.layout.fragment_sensor, container, false);

    final TextView textView = root.findViewById(R.id.text_sensor);

    //final TextView sumaView = root.findViewById(R.id.tvVoltaje);

    /*sensorViewModel.getText().observe(getViewLifecycleOwner(), new Observer<String>() {

      @Override

      public void onChanged(@Nullable String s) {

        textView.setText(s);

      }

    });*/

    return root;

}