Java 我正在尝试使用改造从服务器获取一些数据。但是我找不到哪里'；It’我的密码出了问题

我正在尝试使用改造从服务器获取一些数据，但我的代码有问题，但我自己找不到

package com.example.shobkhana.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 androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;   
import com.bumptech.glide.Glide;
import com.example.shobkhana.Activity.MainActivity;
import com.example.shobkhana.Model.Fooddata;
import com.example.shobkhana.Model.Popular;
import com.example.shobkhana.R;   
import java.util.ArrayList;
import java.util.List;
import java.util.Objects; 
import retrofit2.Callback;

public class PopularAdapter extends RecyclerView.Adapter<PopularAdapter.PopularViewHolder> {

    private  Context context;
    private List<Popular>popularlist;


    public PopularAdapter(@NonNull Context context, List<Popular> popularlist) {
        this.context =context;
        this.popularlist = popularlist;

    }

    @NonNull
    @Override
    public PopularAdapter.PopularViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

        View view=LayoutInflater.from(context).inflate(R.layout.popular,parent,false);

        return new PopularViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull PopularAdapter.PopularViewHolder holder, int position) {
        holder.poptext.setText(popularlist.get(position).getName());
        Glide.with(context).load(popularlist.get(position)).into(holder.popimg);

    }

    @Override
    public int getItemCount() {
        return popularlist.size();
    }

    public class PopularViewHolder extends RecyclerView.ViewHolder {
        TextView poptext;
        ImageView popimg;

        public PopularViewHolder(@NonNull View itemView) {
            super(itemView);
            popimg=itemView.findViewById(R.id.imageView2);
            poptext=itemView.findViewById(R.id.poptext);
        }
    }
}

---

您得到的

onResponse

列表为空列表

fooddataList.get（0.getPopular）（）

---

这就是为什么当您尝试获取

fooddataList

的第一个对象时，会出现空指针异常。因此，请确保您得到的是一个非空列表。

他得到的错误

java.lang.Object java.util.list.get（int）null Object reference

，但如果列表为空，则会引发此异常

java.lang.IndexOutOfBoundsException:Index:0，Size:0

@ShayKin那么我应该如何对其进行编码？

    package com.example.shobkhana.Activity;
    
    import android.os.Bundle;
    import android.widget.Toast;
    
    import androidx.appcompat.app.AppCompatActivity;
    import androidx.recyclerview.widget.LinearLayoutManager;
    import androidx.recyclerview.widget.RecyclerView;
    
    import com.example.shobkhana.Adapter.PopularAdapter;
    import com.example.shobkhana.Model.Fooddata;
    import com.example.shobkhana.Model.Popular;
    import com.example.shobkhana.R;
    import com.example.shobkhana.Retrofit.ApiInterface;
    import com.example.shobkhana.Retrofit.Client;
    
    import java.util.ArrayList;
    import java.util.List;
    
    import retrofit2.Call;
    import retrofit2.Callback;
    import retrofit2.Response;
    
    public class MainActivity extends AppCompatActivity {
    
    
        ApiInterface apiInterface;
        RecyclerView poprecycler;
        PopularAdapter popularAdapter;
        List<Popular>popularList;
    

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            apiInterface= Client.getRetrofitInstance().create(ApiInterface.class);
            Call<List<Fooddata>> call=apiInterface.getAlldata();
            call.enqueue(new Callback<List<Fooddata>>() {
                @Override
                public void onResponse(Call<List<Fooddata>> call, Response<List<Fooddata>> response) {
    
                    List<Fooddata> fooddataList=response.body();
                    getPopulardata(fooddataList.get(0).getPopular());
    
                }
    
                @Override
                public void onFailure(Call<List<Fooddata>> call, Throwable t) {
                    Toast.makeText(getApplicationContext(),"Server not responding",Toast.LENGTH_SHORT).show();
    
                }
            });
        }
    
   private void getPopulardata(List<Popular>popularList){
    
          poprecycler=findViewById(R.id.poprecycle);
          popularAdapter=new PopularAdapter(this,popularList);
          RecyclerView.LayoutManager layoutManager=new LinearLayoutManager(this,LinearLayoutManager.HORIZONTAL,false);
          poprecycler.setLayoutManager(layoutManager);
          poprecycler.setAdapter(popularAdapter);

          }    
    }

Attempt to invoke interface method 'java.lang.Object java.util.List.get(int)' on a null object reference
    at com.example.shobkhana.Activity.MainActivity$1.onResponse(MainActivity.java:51)