Fragment.getView on a null object reference

При определении фрагмента из активити возникает ошибка:

 Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.app.Fragment.getView()' on a null object reference

Код активити:

public class MainActivity extends AppCompatActivity {

    private ActivityMainBinding binding;
    private Bundle b;
    private Toolbar toolbar;
    private List<String> sp_pickpas_list;
    private Spinner sp_pas;

    private View root;

    private ImageButton ib_addpas;
    private RecyclerView rv_fams;
    private LinearLayoutManager llm;
    private AppDatabase db;
    private FamDao fdao;
    private ApiaryDao apdao;
    private String pas_name;
    private Apiary newap;
    private List<Apiary> all;
    private boolean is_pas_picked = false;

    private List<Fam> fams;
    private Intent i_addfam;
    private TextView error;
    private RVA_fam rva_fam;
    private int id_pas;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        b = getIntent().getExtras();

        binding = ActivityMainBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());
        toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        BottomNavigationView navView = findViewById(R.id.nav_view);
        AppBarConfiguration appBarConfiguration = new AppBarConfiguration.Builder(
                R.id.navigation_home, R.id.navigation_dashboard, R.id.navigation_notifications)
                .build();
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_activity_main);
        NavigationUI.setupActionBarWithNavController(this, navController, appBarConfiguration);
        NavigationUI.setupWithNavController(binding.navView, navController);

        if(b!=null && (int)b.get("Statement")==1) Toast.makeText(this, "Семья успешно добавлена", Toast.LENGTH_LONG).show();

        root = getFragmentManager().findFragmentById(R.layout.fragment_home).getView(); //ошибка ссылается на эу строку
        sp_pas = findViewById(R.id.sp_paspick);

        sp_pickpas_list = new ArrayList<String>();
        sp_pickpas_list.add("=Выберите пасеку=");

        rv_fams = root.findViewById(R.id.rv_fams);
        error = root.findViewById(R.id.tv_error);


        newap = new Apiary();
        rv_fams.setVisibility(View.INVISIBLE);
        error.setVisibility(View.VISIBLE);
        i_addfam = new Intent(this, AddFamily.class);
        llm = new LinearLayoutManager(this);
        llm.setOrientation(RecyclerView.VERTICAL);
        rv_fams.setLayoutManager(llm);
        db = app.getInstance().getDatabase();
        fdao = db.FamDao();
        apdao = db.ApiaryDao();
        rva_fam = new RVA_fam();
        rv_fams.setAdapter(rva_fam);

        getListPas();


        ArrayAdapter<String> sp_pas_adap = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, sp_pickpas_list);
        sp_pas.setAdapter(sp_pas_adap);

        sp_pas.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
                if(i!=0) {
                    fams = fdao.getFams(i);
                    if(fams.size()!=0) {
                        Log.i("H_frag", "fams size isnt null");
                        rv_fams.setVisibility(View.VISIBLE);
                        rva_fam.setItems(fams);
                        error.setVisibility(View.INVISIBLE);
                    } else {
                        Log.i("H_frag", "fams size is null");
                        rva_fam.clearItems();
                        rv_fams.setVisibility(View.INVISIBLE);
                        error.setVisibility(View.VISIBLE);
                    }
                    id_pas=i;
                    is_pas_picked = true;
                } else {
                    Log.i("H_frag", "picked null spinner element");
                    rva_fam.clearItems();
                    rv_fams.setVisibility(View.INVISIBLE);
                    error.setVisibility(View.VISIBLE);
                    is_pas_picked = false;
                }
            }
            @Override
            public void onNothingSelected(AdapterView<?> adapterView) {

            }
        });

        ib_addpas.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (is_pas_picked){
                    i_addfam.putExtra("pas_id", id_pas);
                    startActivity(i_addfam);
                } else {
                    CreateDialog(savedInstanceState).show();
                }
            }
        });
    }

    public Dialog CreateDialog(Bundle savedInstanceState) {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Добавить пасеку");
        LayoutInflater li = LayoutInflater.from(this);
        View v = li.inflate(R.layout.ad_add_pas, null);
        builder.setView(v);
        EditText etName = v.findViewById(R.id.et_pasname);
        builder.setPositiveButton("OK",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        pas_name = etName.getText().toString();
                        if (pas_name.compareTo("") == 0) {
                            Toast.makeText(MainActivity.this,
                                    "Поле не заполнено", Toast.LENGTH_SHORT).show();
                        } else {
                            newap.kol_fams = 0;
                            newap.name = pas_name;
                            apdao.insert_apiary(newap);
                            dialog.cancel();
                        }
                    }
                });
        builder.setNegativeButton("ОТМЕНА", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                dialogInterface.cancel();
            }
        });
        return builder.create();
    }

    private void getListPas(){
        all = apdao.getAllfromApiary();
        for(int i=0; i<all.size(); i++){
            sp_pickpas_list.add(all.get(i).name + " (" + all.get(i).kol_fams + ")");
        }
    }




}

Подозреваю, что проблема может быть в том, что переключение между фрагментами реализовано через BottomNavigationView, поэтому прилагаю разметку активити и фрагмента. Кстати, фрагмент без проблем можно было открыть через нажатие кнопки в BottomNavigationView.

Разметка активити:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.appcompat.widget.Toolbar
        android:id="@+id/toolbar"
        style="@style/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        app:layout_constraintTop_toTopOf="parent"
        tools:ignore="MissingConstraints">

        <Spinner
            android:id="@+id/sp_paspick"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="1dp"
            android:layout_marginTop="21dp"
            android:textSize="24sp"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

    </androidx.appcompat.widget.Toolbar>

    <fragment
        android:id="@+id/nav_host_fragment_activity_main"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginTop="60dp"
        app:defaultNavHost="true"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/toolbar"
        app:navGraph="@navigation/mobile_navigation" />

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/nav_view"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="0dp"
        android:layout_marginEnd="0dp"
        android:background="?android:attr/windowBackground"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:menu="@menu/bottom_nav_menu" />



</androidx.constraintlayout.widget.ConstraintLayout>

Разметка фрагмента:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ui.home.HomeFragment">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rv_fams"
        android:layout_width="383dp"
        android:layout_height="653dp"
        android:layout_marginStart="8sp"
        android:layout_marginEnd="8sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.428"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageButton
        android:id="@+id/ib_add"
        android:layout_width="63sp"
        android:layout_height="60sp"
        android:layout_marginEnd="64dp"
        android:layout_marginBottom="64dp"
        android:background="@null"
        android:scaleType="fitXY"
        android:src="@android:drawable/ic_input_add"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent" />

    <TextView
        android:id="@+id/tv_error"
        android:layout_width="252dp"
        android:layout_height="158dp"
        android:layout_marginBottom="284dp"
        android:text="В выбранной пасеке отсутствуют семьи"
        android:textSize="30sp"
        android:textAlignment="center"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.496"
        app:layout_constraintStart_toStartOf="parent" />


</androidx.constraintlayout.widget.ConstraintLayout>

Честно говоря, не знаю как проблему решить, более того, не знаю даже как к ней подступиться. Подскажите, пожалуйста, в чем она может быть. Спасибо!