عدم نمایش recyclerview

سلام پارسا وقتت بخیر 

کد ها رو اگر ممکنه در قالب یک فایل بذارین یا اینکه در قسمتی که میخواین کد ها رو کپی کنین فورمت php رو فکر میکنم بهش بدین بهم نمیریزن 

الان قابل خوندن نیستن.

ممنون میشم این کارو کنین.

MainActivity :
========================================
package com.sevenlearn.a7learnstudents;

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

import android.os.Build;
import android.os.Bundle;
import android.util.EventLogTags;
import android.util.Log;
import android.widget.Toast;

import com.android.volley.DefaultRetryPolicy;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.lang.reflect.Method;
import java.sql.Struct;
import java.util.ArrayList;
import java.util.List;

import javax.security.auth.login.LoginException;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MainActivity";


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Toolbar toolbar = findViewById(R.id.toolbar_main);
        setSupportActionBar(toolbar);

         StringRequest request = new StringRequest(Request.Method.GET, "http://expertdevelopers.ir/api/v1/experts/student",
                 new Response.Listener<String>() {
            @RequiresApi(api = Build.VERSION_CODES.KITKAT)
            @Override
            public void onResponse(String response) {
              //  req.setRetryPolicy(new DefaultRetryPolicy(10000,3,2));
                List<Student> students = new ArrayList<>();
                try {
                    JSONArray jsonArray = new JSONArray(response);
                    for (int i = 0; i < jsonArray.length(); i++) {
                        JSONObject studentJsonObject = jsonArray.getJSONObject(i);
                        Student student = new Student();
                        student.setId(studentJsonObject.getInt("id"));
                        student.setScore(studentJsonObject.getInt("score"));
                        student.setCourse(studentJsonObject.getString("course"));
                        student.setFirstName(studentJsonObject.getString("first_name"));
                        student.setLastName(studentJsonObject.getString("last_name"));
                        students.add(student);

                    }


                    Log.i(TAG, "onResponse: " + students.size());


                    RecyclerView recyclerView = findViewById(R.id.rv_student_main);
                    recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this, RecyclerView.VERTICAL, false));
                    recyclerView.setAdapter(new StudentAdapter(students));
                }

                 catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Log.e(TAG, "onErrorResponse: "+error );
            }
        });

        RequestQueue requestQueue = Volley.newRequestQueue(this);
        requestQueue.add(request);


    }
}
=============================================================


StudentAdapter: 


package com.sevenlearn.a7learnstudents;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import java.util.List;

public class StudentAdapter extends RecyclerView.Adapter<StudentAdapter.SudentViewHolder> {

    private List<Student> students;

    public StudentAdapter(List<Student> students) {
        this.students = students;
    }


    @NonNull
    @Override
    public SudentViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        return new SudentViewHolder(LayoutInflater.from(parent.getContext())
                .inflate(R.layout.item_student,parent,false));
    }

    @Override
    public void onBindViewHolder(@NonNull SudentViewHolder holder, int position) {
        holder.bind(students.get(position));
    }

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

    public class SudentViewHolder extends RecyclerView.ViewHolder {
        private TextView fullNameTv;
        private TextView courseTv;
        private TextView firstCharTv;
        private TextView scoreTv;


        public SudentViewHolder(@NonNull View itemView) {
            super(itemView);
            fullNameTv = itemView.findViewById(R.id.tv_student_fullName);
            courseTv = itemView.findViewById(R.id.tv_student_course);
            firstCharTv = itemView.findViewById(R.id.tv_student_first_character);
            scoreTv = itemView.findViewById(R.id.tv_student_score);
        }

        public void bind(Student student){
           fullNameTv.setText(student.getFirstName()+" "+student.getLastName());
            courseTv.setText(student.getCourse());
            firstCharTv.setText(student.getFirstName().substring(0,1));
            scoreTv.setText(student.getScore());
        }
    }
}