回收站视图分页滚动回收站视图不起作用

Question

在回收站视图中，我想在滚动回收站视图时更新数据。 但是这样做，Recycler视图不会滚动。我的代码是 请给我解决方案，以便我可以继续完成我的项目

package com.piyushjaiswal.lyricswala;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.DividerItemDecoration;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.text.TextUtils;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.appcompat.widget.SearchView;
import android.widget.Toast;

import com.airbnb.lottie.LottieAnimationView;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;
import com.google.firebase.database.ValueEventListener;
import java.util.ArrayList;
import java.util.List;
/**
 * A simple {@link Fragment} subclass.
 */
public class Hindi extends Fragment {

    private List<Contact> listContact = new ArrayList<>();
   private FirebaseDatabase database = FirebaseDatabase.getInstance();
    private  DatabaseReference myRef = database.getReference();
    private  RecyclerViewAdapter recyclerViewAdapter;
    private LottieAnimationView progressBar;
    private SearchView searchView;
    private RecyclerView myRecyclerview;
    private final int ITEM_LOAD_COUNT = 5;
    private int total_item = 0,last_visible_item;
    private boolean isLoading = false, isMaxData = false;
    private String last_node="",last_key="";



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

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.fragment_hindi, container, false);
        progressBar= v.findViewById(R.id.progressbar);
        searchView = v.findViewById(R.id.searchViewinHindi);
        progressBar.setVisibility(View.VISIBLE);
       myRecyclerview = v.findViewById(R.id.recyclerView);

        getLastKeyFromFirebase();
        final LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
        myRecyclerview.setLayoutManager(layoutManager);
        DividerItemDecoration dividerItemDecoration  = new DividerItemDecoration(myRecyclerview.getContext(),layoutManager.getOrientation());
        myRecyclerview.addItemDecoration(dividerItemDecoration);
        RecyclerViewAdapter recyclerViewAdapter = new RecyclerViewAdapter(getContext(),listContact);

        myRecyclerview.setAdapter(recyclerViewAdapter);
        getUsers();


        myRecyclerview.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                total_item = layoutManager.getItemCount();
                last_visible_item = layoutManager.findLastVisibleItemPosition();
                if(!isLoading && total_item <= ((last_visible_item +ITEM_LOAD_COUNT))){
                    getUsers();
                    isLoading=true;

                }            }
        });
        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {


                return false;
            }

            @Override
            public boolean onQueryTextChange(String newText) {

                search(newText);
                return true;
            }
        });
  return v;
    }private void getUsers() {
    if(!isMaxData){
        Query query;
        if(TextUtils.isEmpty(last_node))
            query = FirebaseDatabase.getInstance().getReference().child("Hindi").orderByKey().limitToFirst(ITEM_LOAD_COUNT);
          else
              query = FirebaseDatabase.getInstance().getReference().child("Hindi").orderByKey().startAt(last_node).limitToFirst(ITEM_LOAD_COUNT);

               query.addListenerForSingleValueEvent(new ValueEventListener() {
                   @Override
                   public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                       if(dataSnapshot.hasChildren()){
                           List<Contact> newContact = new ArrayList<>();
                           for(DataSnapshot userSnapshot: dataSnapshot.getChildren()){
                               newContact.add(userSnapshot.getValue(Contact.class));
                           }
                           searchView.setVisibility(View.VISIBLE);
                           progressBar.setVisibility(View.GONE);
                           last_node = newContact.get(newContact.size()-1).getName();
                           if(!last_node.equals(last_key))
                               newContact.remove(newContact.size()-1);
                           else
                               last_node = "end";
                           RecyclerViewAdapter mRecycleradapter = new RecyclerViewAdapter(getContext(),newContact);
                           myRecyclerview.setAdapter(mRecycleradapter);
                           isLoading = false;
      }
                       else
                       {
                  isLoading = false;
                  isMaxData = true;
                       }
                   }
   @Override
                   public void onCancelled(@NonNull DatabaseError databaseError) {
                  isLoading = false;
                   }
               });
    }
    }


    private void getLastKeyFromFirebase()
{
    Query getLastKey = FirebaseDatabase.getInstance().getReference().child("Hindi").orderByKey().limitToLast(1);
    getLastKey.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            for(DataSnapshot dataSnapshot1:dataSnapshot.getChildren()){
                last_key = dataSnapshot1.getKey();
            }
}       @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {
       Toast.makeText(getActivity(),databaseError.getMessage(),Toast.LENGTH_LONG).show();

        }
    });

}

    private void search(String newText) {

        ArrayList<Contact> myList = new ArrayList<>();
        for (Contact object : listContact) {
            if(object.getName().toLowerCase().contains(newText.toLowerCase()))
            {
                myList.add(object);
            }

        }
        RecyclerViewAdapter recyclerViewAdapter = new RecyclerViewAdapter(getContext(),myList);
        myRecyclerview.setAdapter(recyclerViewAdapter);

    }



}

运行我的应用程序时，它仅显示4个项目，但在Firebase数据库中创建了7个节点。