How to Implement RecyclerView in a Fragment in Android?

package com.example.gfg;

import java.io.Serializable;

public class Employee implements Serializable {
    private final String name;   // name of the employee
    private final String email;  // email of the employee

    public Employee(String name, String email) {
        this.name = name;
        this.email = email;
    }

    public String getName() {
        return name;
    }

    public String getEmail() {
        return email;
    }
}

package com.example.gfg;

import java.util.ArrayList;

public class Constants {
    // ArrayList and return the ArrayList
    public static ArrayList<Employee> getEmployeeData()
    {
        // create an ArrayList of type Employee class
        ArrayList<Employee> employeeList
            = new ArrayList<Employee>();
        Employee emp1 = new Employee("Chinmaya Mohapatra",
                                     "chinmaya@gmail.com");
        employeeList.add(emp1);
        Employee emp2
            = new Employee("Ram prakash", "ramp@gmail.com");
        employeeList.add(emp2);
        Employee emp3 = new Employee("OMM Meheta",
                                     "mehetaom@gmail.com");
        employeeList.add(emp3);
        Employee emp4 = new Employee("Hari Mohapatra",
                                     "harim@gmail.com");
        employeeList.add(emp4);
        Employee emp5 = new Employee(
            "Abhisek Mishra", "mishraabhi@gmail.com");
        employeeList.add(emp5);
        Employee emp6 = new Employee("Sindhu Malhotra",
                                     "sindhu@gmail.com");
        employeeList.add(emp6);
        Employee emp7 = new Employee("Anil sidhu",
                                     "sidhuanil@gmail.com");
        employeeList.add(emp7);
        Employee emp8 = new Employee("Sachin sinha",
                                     "sinhas@gmail.com");
        employeeList.add(emp8);
        Employee emp9 = new Employee("Amit sahoo",
                                     "sahooamit@gmail.com");
        employeeList.add(emp9);
        Employee emp10 = new Employee("Raj kumar",
                                      "kumarraj@gmail.com");
        employeeList.add(emp10);

        return employeeList;
    }
}

package com.example.gfg;

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

import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;

public class Adapter extends RecyclerView.Adapter<Adapter.MyViewHolder> {
    private ArrayList<Employee> emplist;

    public Adapter(ArrayList<Employee> emplist) {
        this.emplist = emplist;
    }

    // This method creates a new ViewHolder object for each item in the RecyclerView
    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        // Inflate the layout for each item and return a new ViewHolder object
        View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.items_list, parent, false);
        return new MyViewHolder(itemView);
    }

    // This method returns the total 
    // number of items in the data set
    @Override
    public int getItemCount() {
        return emplist.size();
    }

    // This method binds the data to the ViewHolder object 
    // for each item in the RecyclerView
    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        Employee currentEmp = emplist.get(position);
        holder.name.setText(currentEmp.getName());
        holder.email.setText(currentEmp.getEmail());
    }

    // This class defines the ViewHolder object for each item in the RecyclerView
    public static class MyViewHolder extends RecyclerView.ViewHolder {
        private TextView name;
        private TextView email;

        public MyViewHolder(View itemView) {
            super(itemView);
            name = itemView.findViewById(R.id.tvName);
            email = itemView.findViewById(R.id.tvEmail);
        }
    }
}

@Override
public void
onViewCreated(@NonNull View view,
              @Nullable Bundle savedInstanceState)
{
    super.onViewCreated(view, savedInstanceState);
    // getting the employeelist
    ArrayList<Employee> employelist
        = Constants.getEmployeeData();
    // Assign employeelist to ItemAdapter
    Adapter itemAdapter = new Adapter(employelist);
    // Set the LayoutManager that
    // this RecyclerView will use.
    RecyclerView recyclerView
        = view.findViewById(R.id.recycleView);
    recyclerView.setLayoutManager(
        new LinearLayoutManager(getContext()));
    // adapter instance is set to the
    // recyclerview to inflate the items.
    recyclerView.setAdapter(itemAdapter);
}

package com.example.gfg;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

public class FirstFragment extends Fragment {
    private String param1;
    private String param2;
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            param1 = getArguments().getString("param1");
            param2 = getArguments().getString("param2");
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater,
                             ViewGroup container,
                             Bundle savedInstanceState)
    {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_first,
                                container, false);
    }

    public static FirstFragment newInstance(String param1,
                                            String param2)
    {
        FirstFragment fragment = new FirstFragment();
        Bundle args = new Bundle();
        args.putString("param1", param1);
        args.putString("param2", param2);
        fragment.setArguments(args);
        return fragment;
    }

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

        // getting the employeelist
        ArrayList<Employee> employelist
            = Constants.getEmployeeData();

        // Assign employeelist to ItemAdapter
        Adapter itemAdapter = new Adapter(employelist);

        // Set the LayoutManager that
        // this RecyclerView will use.
        RecyclerView recyclerView
            = view.findViewById(R.id.recycleView);
        recyclerView.setLayoutManager(
            new LinearLayoutManager(getContext()));

        // adapter instance is set to the
        // recyclerview to inflate the items.
        recyclerView.setAdapter(itemAdapter);
    }
}

package com.example.gfg;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get a reference to the "btn_frag" button from the
        // layout
        Button btn = findViewById(R.id.btn_frag);

        // Set an OnClickListener on the button
        btn.setOnClickListener(new View.OnClickListener() {
            @Override public void onClick(View v)
            {
                // When the button is clicked, replace
                // the current fragment with a new
                // instance of the FirstFragment
                replaceFragment(new FirstFragment());

                // Hide the button
                btn.setVisibility(View.GONE);
            }
        });
    }

    // This method replaces the current fragment
    // with a new fragment
    public void replaceFragment(Fragment fragment)
    {
        // Get a reference to the FragmentManager
        androidx.fragment.app
            .FragmentManager fragmentManager
            = getSupportFragmentManager();

        // Start a new FragmentTransaction
        androidx.fragment.app
            .FragmentTransaction fragmentTransaction
            = fragmentManager.beginTransaction();

        // Replace the current fragment with the new
        // fragment
        fragmentTransaction.replace(R.id.frame_layout,
                                    fragment);

        // Commit the FragmentTransaction
        fragmentTransaction.commit();
    }
}