you can try this it works for me. Override the onActivityCreated() method and do this.

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        Button btnHospital = getActivity().findViewById(R.id.BtnInfoHospital);
        /// All buttons

        btnHospital.setOnClickListener(this);
        // All buttons
    }

I hope it helps you regards

I have a 3 fragment, and in the last fragment I have some buttons to redirect user to open a link,
enter image description here
but it doesn’t work. here is my fragment activity

package com.vyzyz.covidupdate.fragment;


import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;

import androidx.fragment.app.Fragment;

import com.vyzyz.covidupdate.R;


/**
* A simple {@link Fragment} subclass.
*/
public class InfoFragment extends Fragment implements View.OnClickListener {

   public InfoFragment() {
       // Required empty public constructor
   }


   @Override
   public View onCreateView(LayoutInflater inflater, ViewGroup container,
                            Bundle savedInstanceState) {
       // Inflate the layout for this fragment
       View v = inflater.inflate(R.layout.fragment_info, container, false);


       Button btnHospital = (Button)v.findViewById(R.id.BtnInfoHospital);
       Button btnSymptom = (Button)v.findViewById(R.id.BtnInfoSymptom);
       Button btnPrevention = (Button)v.findViewById(R.id.BtnInfoPrevention);
       Button btnAdviceWho = (Button)v.findViewById(R.id.BtnInfoAdviceWho);

       btnHospital.setOnClickListener(this);
       btnSymptom.setOnClickListener(this);
       btnPrevention.setOnClickListener(this);
       btnAdviceWho.setOnClickListener(this);
       return v;
   }

   @Override
   public boolean onOptionsItemSelected(MenuItem item) {
       if (item.getItemId() == android.R.id.home) {

       }
       return super.onOptionsItemSelected(item);
   }

   @Override
   public void onClick(View v) {
       switch (v.getId()) {
           case R.id.btnInfoHospital:
               String hospitalUrl = "https://news.detik.com/berita/d-4942353/daftar-rumah-sakit-rujukan-covid-19-seluruh-indonesia?single=1";
               Uri hospitalUri = Uri.parse(hospitalUrl);
               Intent intentInfoHospital = new Intent(Intent.ACTION_VIEW, hospitalUri);
              // Toast.makeText(this, getResources().getString(R.string.redirect), Toast.LENGTH_SHORT).show();
               startActivity(intentInfoHospital);
               break;

           case R.id.btnInfoSymptom:
               String symptomUrl = "https://www.cnnindonesia.com/gaya-hidup/20200128205625-258-469589/infografis-bedanya-demam-selesma-dan-virus-corona-wuhan";
               Uri symptomUri = Uri.parse(symptomUrl);
               Intent intentInfoSymptom = new Intent(Intent.ACTION_VIEW, symptomUri);
               //Toast.makeText(this, getResources().getString(R.string.redirect), Toast.LENGTH_SHORT).show();
               startActivity(intentInfoSymptom);
               break;

           case R.id.btnInfoPrevention:
               String urlPrevention = "https://www.kompas.com/sains/read/2020/03/15/190200123/panduan-mencegah-virus-corona-pesan-who-untuk-kita-semua?page=all#page4";
               Uri preventionUri = Uri.parse(urlPrevention);
               Intent intentPrevention = new Intent(Intent.ACTION_VIEW, preventionUri);
               //Toast.makeText(this, getResources().getString(R.string.redirect), Toast.LENGTH_SHORT).show();
               startActivity(intentPrevention);
               break;

           case R.id.btnInfoAdviceWho:
               String urlWho = "https://www.youtube.com/watch?v=bPITHEiFWLc&feature=emb_title";
               Uri whoUri = Uri.parse(urlWho);
               Intent intentWho = new Intent(Intent.ACTION_VIEW, whoUri);
              // Toast.makeText(this, getResources().getString(R.string.redirect), Toast.LENGTH_SHORT).show();
               startActivity(intentWho);
               break;
       }
   }
}

and here is my main, activity

package com.vyzyz.covidupdate.activity;

import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import com.google.android.material.bottomnavigation.BottomNavigationView;

import com.vyzyz.covidupdate.R;
import com.vyzyz.covidupdate.fragment.IdnFragment;
import com.vyzyz.covidupdate.fragment.InfoFragment;
import com.vyzyz.covidupdate.fragment.SummaryFragment;

public class MainActivity extends AppCompatActivity implements BottomNavigationView.OnNavigationItemSelectedListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //Menampilkan Fragment Summary Ketika App Dibuka
        SummaryFragment summaryFragment = new SummaryFragment();
        getSupportFragmentManager()
                .beginTransaction()
                .add(R.id.main_frame,summaryFragment)
                .commit();

        BottomNavigationView bottomNavigationView = findViewById(R.id.bottomNav);
        bottomNavigationView.setOnNavigationItemSelectedListener(this);


    }

    //Menu Navigasi Bawah
    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
        switch (item.getItemId()){
            //Ke Fragment Summary
            case R.id.summaryMenu:
                SummaryFragment summaryFragment = new SummaryFragment();
                getSupportFragmentManager()
                        .beginTransaction()
                        .replace(R.id.main_frame,summaryFragment)
                        .commit();
                return true;

            //Ke Fragment Idn
            case R.id.summaryIdnMenu:
                IdnFragment idnFragment = new IdnFragment();
                getSupportFragmentManager()
                        .beginTransaction()
                        .replace(R.id.main_frame,idnFragment)
                        .commit();
                return true;

            //ke Fragment News
            case R.id.infoMenu:
              InfoFragment infoFragment = new InfoFragment();
                getSupportFragmentManager()
                        .beginTransaction()
                        .replace(R.id.main_frame,infoFragment)
                        .commit();
                return true;
        }
        return false;
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        //menampilkan menu utama
        getMenuInflater().inflate(R.menu.main_menu,menu);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        //Memilih Masing-Masing Menu pada main menu
        switch (item.getItemId()) {
           //Ke activity About
           case R.id.aboutMenu:
                Intent intentAbout = new Intent(this, AboutActivity.class);
                startActivity(intentAbout);
                break;
        }
        return super.onOptionsItemSelected(item);
    }
}

i’ve tried to move that fragment to basic activity and the button is work, but, when turn back to fragment, the button doesn’t work anymore. I’ve searching same problem in this site, but it cannot solve my problem.
Anyone can please help me?