java - 我在我的 firebase recyclerview 适配器的 logcat “E/RecyclerView：未连接适配器；跳过布局”中收到以下错误

Question

我遇到了其他编码员面临的类似问题，但他们至少在回收站视图中显示了数据，在我的回收站视图中没有显示任何内容，回收站视图为空，我的 firebase 数据库也不为空。没有显示其他指示数据库问题的错误消息。我需要对我的代码进行的更改的代码片段将非常有帮助，因为我是使用 Android Studios 编程的新手。

主要活动代码

    package com.example.jamsecure;

import android.os.Bundle;
import android.widget.Toast;

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.ValueEventListener;

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

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

public class User_Select_Jam_Studio extends AppCompatActivity {

    List<FetchData> fetchData;
    RecyclerView recyclerView;
    HelperAdapter helperAdapter;
    DatabaseReference databaseReference;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_user__select__jam__studio);
        recyclerView=findViewById(R.id.recyclerview);
        recyclerView.setLayoutManager((new LinearLayoutManager(this)));
        fetchData=new ArrayList<>();

        databaseReference= FirebaseDatabase.getInstance().getReference("Owners");

        databaseReference.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                for(DataSnapshot ds:dataSnapshot.getChildren())
                {
                    FetchData data=ds.getValue(FetchData.class);
                    fetchData.add(data);
                }
                helperAdapter=new HelperAdapter(fetchData);
                recyclerView.setAdapter(helperAdapter);
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error) {
                Toast.makeText(User_Select_Jam_Studio.this,"Data base problem",Toast.LENGTH_LONG).show();
            }
        });

    }
}

HelperAdapter.java

    package com.example.jamsecure;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.util.List;

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

public class HelperAdapter extends RecyclerView.Adapter {
    List<FetchData> fetchDataList;

    public HelperAdapter(List<FetchData> fetchDataList) {
        this.fetchDataList = fetchDataList;
    }

    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.jamrooms,parent, false);
        ViewHolderClass viewHolderClass = new ViewHolderClass(view);
        return viewHolderClass;
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
    ViewHolderClass viewHolderClass=(ViewHolderClass)holder;
        FetchData fetchData=fetchDataList.get(position);
        viewHolderClass.name.setText(fetchData.getName());
        viewHolderClass.jamr.setText(fetchData.getJamrate());
        viewHolderClass.mob.setText(fetchData.getMob());

     }

    @Override
    public int getItemCount() {
        return fetchDataList.size();
    }
    public class ViewHolderClass extends RecyclerView.ViewHolder{
        TextView name,jamr,mob;
        public ViewHolderClass(@NonNull View itemView) {
            super(itemView);
            name=itemView.findViewById(R.id.name);
            jamr=itemView.findViewById(R.id.jamrate);
            mob=itemView.findViewById(R.id.mob);
        }
    }
}

获取数据.java

package com.example.jamsecure;

public class FetchData {
    String sname;
    String jam_rate;
    String phone;

    public FetchData( String name, String jamrate, String mob) {
        this.sname = name;
        this.jam_rate = jamrate;
        this.phone = mob;
    }
    public FetchData(){}

    public String getName() {
        return sname;
    }

    public String getJamrate() {
        return jam_rate;
    }

    public String getMob() {
        return phone;
    }

}

标签： javaandroidfirebase-realtime-databaseandroid-recyclerview