Я не могу получить RecyclerView, чтобы показать его элементы во фрагменте внутри BottomNavigation. Я прочитал все темы об этом, но ничего не получалось

Question

Итак, у меня есть этот проект для java android, и я все перепробовал. Буквально я прочитал все темы об этом и перепробовал все, но, кажется, ничего не работает. Элементы в RecyclerView просто не будут отображаться.

Я скоро создаю компанию. Если вы сможете решить эту проблему, я буду заинтересован в найме ваших услуг в будущем.

Итак, вот мой код:

Активность:

package com.android.neto.myproject.activity;

import android.app.SearchManager;
import android.content.Context;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ProgressBar;
import android.widget.SearchView;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentTransaction;
import androidx.recyclerview.widget.RecyclerView;

import com.android.neto.myproject.R;
import com.android.neto.myproject.config.FirebaseConfig;
import com.android.neto.myproject.fragment.UserInterestsFragment;
import com.android.neto.myproject.fragment.UserAppointmentsFragment;
import com.android.neto.myproject.fragment.UserFriendsFragment;
import com.android.neto.myproject.model.User;
import com.google.android.material.bottomnavigation.BottomNavigationView;

public class UserActivity extends AppCompatActivity {

    private User user;

    private BottomNavigationView navView;
    private SearchManager searchManager;
    private SearchView search;
    private Fragment currentFragment;
    private int currentNavigation;

    private ProgressBar progressBar;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_user);

        user = (User)getIntent().getSerializableExtra("user");

        initializeComponents();
    }

    @Override
    protected void onStart() {

        super.onStart();
    }

    private void initializeComponents() {

        progressBar = findViewById(R.id.progressBar);

        navView = findViewById(R.id.nav_view);
        currentNavigation = R.id.navigation_user_friends;

        currentFragment = new UserFriendsFragment();
        loadFragment();
        setTitle(R.string.title_user_friends);

        navView.setOnNavigationItemSelectedListener(
                new BottomNavigationView.OnNavigationItemSelectedListener() {
                @Override public boolean onNavigationItemSelected(@NonNull MenuItem item) {


            if (!search.getQuery().toString().isEmpty())    {

                search.setQuery("", false);

                if (!search.isIconified()) {

                    search.setIconified(true);
                } else {

                    UserActivity.super.onBackPressed();

                }
            } else {

                search.setIconified(true);
            }


            currentNavigation = item.getItemId();

            switch (currentNavigation) {

                case R.id.navigation_user_friends:

                    setTitle(R.string.title_user_friends);
                    currentFragment = new UserFriendsFragment();
                    break;

                case R.id.navigation_user_interests:

                    setTitle(R.string.title_user_interests);
                    currentFragment = new UserInterestsFragment();
                    break;

                case R.id.navigation_user_appointments:

                    setTitle(R.string.title_user_appointments);
                    currentFragment = new UserAppointmentsFragment();
                    break;
            }

            return loadFragment();
        }});
    }

    private boolean loadFragment() {

        if (currentFragment != null) {

            Bundle bundle = new Bundle();
            bundle.putSerializable("user", user);
            currentFragment.setArguments(bundle);

            FragmentTransaction fragmentTransaction =  getSupportFragmentManager()
                    .beginTransaction();

            fragmentTransaction
                    .replace(R.id.nav_host_fragment, currentFragment)
                    .commit();

            return true;
        }

        return false;
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        getMenuInflater().inflate(R.menu.menu_user, menu);

        searchManager = (SearchManager)getSystemService(Context.SEARCH_SERVICE);
        search = (SearchView) menu.findItem(R.id.searchBar).getActionView();
        search.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));

        search.setOnQueryTextListener(new SearchView.OnQueryTextListener() {

            @Override
            public boolean onQueryTextSubmit(String query) {

                return false;
            }

            @Override
            public boolean onQueryTextChange(String newText) {

                if (currentFragment != null)    {

                    switch (currentNavigation) {

                        case R.id.navigation_user_friends:

                            break;
                    }
                }

                return false;
            }
        });

        return true;
    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {

        switch (item.getItemId())   {

            case R.id.signOut:

                FirebaseConfig.getAuth().signOut();
                finish();
                break;
            case R.id.update:

                notifyDatasetChanged();
                break;
        }

        return super.onOptionsItemSelected(item);
    }

    public void notifyDatasetChanged()  {

        if (currentFragment != null)    {

            switch (currentNavigation) {

                case R.id.navigation_user_friends:

                    runOnUiThread(new Runnable() {
                            @Override public void run() {

                        RecyclerView friendsRecyclerView =  currentFragment
                                .getView().findViewById(R.id.friendsRecyclerView);
                        friendsRecyclerView.getAdapter().notifyDataSetChanged();
                    }});

                    break;

                case R.id.navigation_user_interests:

                    break;

                case R.id.navigation_user_appointments:

                    break;
            }
        }
    }

    @Override
    public void onBackPressed() {


    }
}

Фрагмент

package com.android.neto.myproject.fragment;

import android.annotation.SuppressLint;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import com.android.neto.myproject.DAO.FriendDAO;
import com.android.neto.myproject.R;
import com.android.neto.myproject.activity.UserActivity;
import com.android.neto.myproject.adapter.UserFriendsRecyclerViewAdapter;
import com.android.neto.myproject.config.FirebaseConfig;
import com.android.neto.myproject.model.Hobby;
import com.android.neto.myproject.model.Friend;
import com.android.neto.myproject.model.User;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.ValueEventListener;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class UserFriendsFragment extends Fragment {

    private View root;
    private UserActivity userActivity;

    private User user;
    private List<Hobby> hobbys;
    private List<Friend> friends;

    private String search = "";

    private RecyclerView friendsRecyclerView;
    private UserFriendsRecyclerViewAdapter userFriendsRecyclerViewAdapter;

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
    }

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

        root = inflater.inflate(R.layout.fragment_user_friends, null);

        user = (User)this.getArguments().getSerializable("user");

        hobbys = new ArrayList<>();
        friends = new ArrayList<>();

        initializeComponents();

        searchHobbys(new AsyncTask<Void, Void, Void>() {
            @Override protected Void doInBackground(Void... voids) {
                searchFriends(new AsyncTask<Void, Void, Void>() {
                    @Override protected Void doInBackground(Void... voids) {

            Log.d("Friends", String.valueOf(friends.size()));
            Log.d("Hobbys", String.valueOf(hobbys.size()));
            Log.d("Activity", userActivity.toString());

            userActivity.notifyDatasetChanged();
        return null;}});return null;}});

        return root;
    }

    @SuppressLint("StaticFieldLeak")
    private void searchHobbys(final AsyncTask<Void, Void, Void> asyncTask) {

        FirebaseConfig.getDatabaseReference().child("hobbys")
                .addListenerForSingleValueEvent(new ValueEventListener() {

            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

                Iterator<DataSnapshot> iterator = dataSnapshot.getChildren().iterator();

                while (iterator.hasNext())  {

                    DataSnapshot current = iterator.next();

                    Hobby hobby = new Hobby();
                    hobby.setKey(current.getKey());
                    hobby.setValue((String)current.getValue());
                    hobby.setChecked(true);

                    hobbys.add(hobby);
                }

                asyncTask.execute();
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });
    }

    private void initializeComponents() {

        friendsRecyclerView = root.findViewById(R.id.friendsRecyclerView);
        RecyclerView.LayoutManager layoutManager =
                new LinearLayoutManager(userActivity);
        friendsRecyclerView.setLayoutManager(layoutManager);
        friendsRecyclerView.setHasFixedSize(true);
        userFriendsRecyclerViewAdapter = new UserFriendsRecyclerViewAdapter(
                friends, hobbys, userActivity);

        userActivity.runOnUiThread(new Runnable() {

            @Override
            public void run() {

                friendsRecyclerView.setAdapter(userFriendsRecyclerViewAdapter);
            }
        });
    }

    @SuppressLint("StaticFieldLeak")
    private void searchFriends(final AsyncTask<Void, Void, Void> asyncTask)  {

        new FriendDAO().getAll(new AsyncTask<List<Friend>, Void, Void>() {
                @Override protected Void doInBackground(List<Friend>... lists) {

            friends = lists[0];

            asyncTask.execute();

            return null;
        }});
    }

    @Override
    public void onAttach(@NonNull Context context) {

        super.onAttach(context);

        userActivity = (UserActivity)context;
    }
}

RecyclerViewAdapter:

package com.android.neto.myproject.adapter;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import com.android.neto.myproject.R;
import com.android.neto.myproject.model.Hobby;
import com.android.neto.myproject.model.Friend;
import com.squareup.picasso.Picasso;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class UserFriendsRecyclerViewAdapter
        extends RecyclerView.Adapter<UserFriendsRecyclerViewAdapter
        .UserFriendsRecyclerViewViewHolder> {

    private List<Friend> friends;
    private List<Hobby> hobbysFromDatabase;
    private Context context;
    private Map<String, String> hobbysReference;

    public UserFriendsRecyclerViewAdapter(List<Friend> friends,
                                            List<Hobby> hobbysFromDatabase, Context context) {

        this.friends = friends;
        this.hobbysFromDatabase = hobbysFromDatabase;
        this.context = context;

        hobbysReference = new HashMap<>();
        for(Hobby hobby : hobbysFromDatabase) {

            hobbysReference.put(hobby.getKey(), hobby.getValue());
        }
    }

    public class UserFriendsRecyclerViewViewHolder extends RecyclerView.ViewHolder implements
            View.OnClickListener {

        ImageView friendImageView;
        TextView friendNameTextView;
        TextView friendNameThreeDotsTextView;
        TextView friendDistanceTextView;
        TextView hobbysTextView;
        TextView hobbysThreeDotsTextView;

        public UserFriendsRecyclerViewViewHolder(@NonNull View itemView) {

            super(itemView);

            itemView.setOnClickListener(this);

            friendImageView = itemView.findViewById(R.id.friendImageView);
            friendNameTextView = itemView.findViewById(R.id.friendNameTextView);
            friendNameThreeDotsTextView = itemView.findViewById(R.id.friendNameThreeDotsTextView);
            friendDistanceTextView = itemView.findViewById(R.id.friendDistanceTextView);
            hobbysTextView = itemView.findViewById(R.id.hobbysTextView);
            hobbysThreeDotsTextView = itemView.findViewById(R.id.hobbysThreeDotsTextView);
        }

        @Override
        public void onClick(View v) {

            int position = getAdapterPosition();
            Friend friend = friends.get(position);
            Toast.makeText(context, friend.getNickName(), Toast.LENGTH_SHORT).show();
            notifyDataSetChanged();
        }
    }

    @NonNull
    @Override
    public UserFriendsRecyclerViewViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

        View item = LayoutInflater.from(parent.getContext()).inflate(
                R.layout.item_friends, parent, false);

        return new UserFriendsRecyclerViewViewHolder(item);
    }

    @Override
    public void onBindViewHolder(@NonNull UserFriendsRecyclerViewViewHolder holder, int position) {

        Friend friend = friends.get(position);

        Picasso.get().load(friend.getRoundedProfileImageUri())
                .into(holder.friendImageView);

        holder.friendNameTextView.setText(friend.getNickName());
        if (holder.friendNameTextView.getLineCount() >
                holder.friendNameTextView.getMaxLines()) {

            holder.friendNameThreeDotsTextView.setVisibility(View.VISIBLE);
        }

        holder.friendDistanceTextView.setText("1,6 km");

        StringBuilder hobbysText = new StringBuilder();
        List<Hobby> hobbys = friend.getHobbys();
        for (int i = 0; i < hobbys.size(); i++)   {

            Hobby hobby = hobbys.get(i);

            if (hobbysReference.containsKey(hobby.getKey()))    {

                hobbysText.append(hobbysReference.get(hobby.getKey()));

                if (i != hobbys.size() - 1)   {

                    hobbysText.append(", ");
                }
            }
        }

        holder.hobbysTextView.setText(hobbysText.toString());
        if (holder.hobbysTextView.getLineCount() >
                holder.hobbysTextView.getMaxLines()) {

            holder.hobbysThreeDotsTextView.setVisibility(View.VISIBLE);
        }
    }

    @Override
    public int getItemCount() {

        return friends.size();
    }
}

Вид деятельности:

<?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=".activity.UserActivity">

    <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/user_bottom_nav_menu" />

    <fragment
        android:id="@+id/nav_host_fragment"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:layout_constraintBottom_toTopOf="@id/nav_view"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:menu="@menu/user_bottom_nav_menu" />

    <ProgressBar
        android:id="@+id/progressBar"
        android:visibility="gone"
        style="?android:attr/progressBarStyle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"/>

</androidx.constraintlayout.widget.ConstraintLayout>

Просмотр 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=".fragment.UserFriendsFragment">


    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/friendsRecyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:paddingBottom="4dp"/>

</androidx.constraintlayout.widget.ConstraintLayout>

Просмотр ViewHolder:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="4dp"
    android:layout_marginStart="4dp"
    android:layout_marginEnd="4dp"
    android:padding="4dp"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <androidx.cardview.widget.CardView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:clickable="true"
        android:focusable="true"
        android:foreground="?android:attr/selectableItemBackground">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:padding="8dp">

            <ImageView
                android:id="@+id/friendImageView"
                android:layout_width="88dp"
                android:layout_height="88dp"
                android:layout_marginEnd="8dp"
                android:scaleType="centerCrop"
                android:src="@drawable/ic_person_primary_color_24dp"
                android:layout_gravity="center"/>

            <LinearLayout
                android:orientation="vertical"
                android:layout_width="match_parent"
                android:layout_height="wrap_content">

                <androidx.constraintlayout.widget.ConstraintLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginBottom="8dp">

                    <TextView
                        android:id="@+id/friendNameTextView"
                        android:layout_width="0dp"
                        android:layout_height="wrap_content"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintEnd_toStartOf="@id/friendDistanceTextView"
                        app:layout_constraintTop_toTopOf="parent"
                        android:layout_marginEnd="8dp"
                        android:maxLines="1"
                        android:ellipsize="end"
                        android:textStyle="bold"
                        android:textSize="16sp"/>

                    <TextView
                        android:id="@+id/friendNameThreeDotsTextView"
                        android:visibility="gone"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:textStyle="bold"
                        android:textSize="16sp"
                        android:text="..."
                        android:background="@android:color/white"
                        app:layout_constraintTop_toTopOf="parent"
                        app:layout_constraintEnd_toEndOf="@id/friendNameTextView"/>

                    <TextView
                        android:id="@+id/friendDistanceTextView"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintTop_toTopOf="parent"
                        app:layout_constraintBottom_toBottomOf="parent"
                        android:text="100,6 km"
                        android:textSize="16sp"
                        android:textColor="@color/colorPrimaryDark"/>

                </androidx.constraintlayout.widget.ConstraintLayout>

                <TextView
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="Hobbys:"
                    android:textSize="16sp"
                    android:textColor="@color/colorPrimaryDark"/>

                <androidx.constraintlayout.widget.ConstraintLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content">

                    <TextView
                        android:id="@+id/hobbysTextView"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:ellipsize="end"
                        android:maxLines="2"
                        android:scrollbars="horizontal"
                        android:textSize="12sp"
                        app:layout_constraintTop_toTopOf="parent"
                        app:layout_constraintStart_toStartOf="parent"/>

                    <TextView
                        android:id="@+id/hobbysThreeDotsTextView"
                        android:visibility="gone"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:textSize="12sp"
                        android:text="..."
                        android:background="@android:color/white"
                        app:layout_constraintBottom_toBottomOf="parent"
                        app:layout_constraintEnd_toEndOf="@id/hobbysTextView"/>

                </androidx.constraintlayout.widget.ConstraintLayout>


            </LinearLayout>

        </LinearLayout>

    </androidx.cardview.widget.CardView>

</LinearLayout>

Если вы, ребята, можете мне помочь, это было бы замечательно Заранее спасибо.