Recylcerview in android studio

 crete three things:-

1.main.class

2.modal class (for firebase)

3.adapter class 

AND XML FILE

main.class

package com.atech.exammind.classes;

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

import android.os.Bundle;
import android.view.MenuItem;

import com.atech.exammind.ClassModal;
import com.atech.exammind.R;
import com.atech.exammind.SubjectRecylerAdapter;

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

public class NinthClass extends AppCompatActivity {


    private RecyclerView myrecylerView;
    public List<ClassModal> myClass;

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

        myClass = new ArrayList<>();
        myClass.add(new ClassModal("MATH",R.drawable.amit));
        myClass.add(new ClassModal("PHYSICS",R.drawable.b));
        myClass.add(new ClassModal("CHEMISTRY",R.drawable.c));
        myClass.add(new ClassModal("BIOLOGY",R.drawable.download));

        Toolbar toolbar = findViewById(R.id.toolBar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setTitle(getIntent().getStringExtra("title"));

        myrecylerView = (RecyclerView)findViewById(R.id.subjectRecyler);

        GridLayoutManager gridLayoutManager = new GridLayoutManager(getApplicationContext(),2, LinearLayoutManager.VERTICAL,false);
        myrecylerView.setLayoutManager(gridLayoutManager);

        RecylerAdapter recylerAdapter = new RecylerAdapter(this,myClass);
        myrecylerView.setAdapter(recylerAdapter);




    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
        if (item.getItemId() == android.R.id.home) {
            finish();
        }
        return super.onOptionsItemSelected(item);
    }
    }

modAL CLSS :-

package com.atech.exammind;

public class ClassModal {

    private String title;
    private  int Image;

    public ClassModal(String title, int image) {
        this.title = title;
        Image = image;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public int getImage() {
        return Image;
    }

    public void setImage(int image) {
        Image = image;
    }
}

ADAPTER CLASS:-

package com.atech.exammind;

import android.content.Context;
import android.content.Intent;
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.atech.exammind.classes.NinthClass;

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

public class ClassRecylerAdapter extends RecyclerView.Adapter<ClassRecylerAdapter.myViewHolder> {

    Context mContext;
    public List<ClassModal> mClass = new ArrayList<>();

    public ClassRecylerAdapter(Context mContext, List<ClassModal> mClass) {
        this.mContext = mContext;
        this.mClass = mClass;
    }

    @NonNull
    @Override
    public myViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View v;
        v = LayoutInflater.from(mContext).inflate(R.layout.class_grid,parent,false);
        myViewHolder vHolder = new myViewHolder(v);


        return vHolder;
    }

    @Override
    public void onBindViewHolder(@NonNull myViewHolder holder, int position)  {

        holder.title.setText(mClass.get(position).getTitle());
        holder.Image.setImageResource(mClass.get(position).getImage() );




    }

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


    public static class myViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

        private TextView title;
        private ImageView Image;

        public myViewHolder(@NonNull View itemView) {
            super(itemView);


            title = (TextView) itemView.findViewById(R.id.classGridText);
            Image = (ImageView) itemView.findViewById(R.id.classGridImage);
            itemView.setClickable(true);
            itemView.setOnClickListener(this);
        }


        @Override
        public void onClick(View v) {
            Intent intent;
            switch (getAdapterPosition()) {
                case 0:
                    intent = new Intent(itemView.getContext(), NinthClass.class);
                    break;

                case 1:
                    intent = new Intent(itemView.getContext(),SubjectActivity.class);
                    break;

                case 2:
                    intent = new Intent(itemView.getContext(),TabActivity.class);
                    break;
                default:
                    intent = new Intent(itemView.getContext(),MainActivity.class);
                    break;

            }
            itemView.getContext().startActivity(intent);
        }
    }

    }

FOR TABBED ACTIVIY  

IN FRGEMENT:-

MAIN ACTIVITY

package com.atech.exammind;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

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

public class ClassActivity extends Fragment {

private RecyclerView myrecylerView;
public List<ClassModal> myClass;

public ClassActivity() {

}



    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.activty_class, container, false);
        myrecylerView = (RecyclerView)rootView.findViewById(R.id.ClassRecyler);
        ClassRecylerAdapter recylerAdapter = new ClassRecylerAdapter(getContext(),myClass);
        myrecylerView.setLayoutManager(new GridLayoutManager(getActivity() ,2));
        myrecylerView.setAdapter(recylerAdapter);
        return rootView;

    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        myClass = new ArrayList<>();
        myClass.add(new ClassModal("CLASS 9",R.drawable.amit));
        myClass.add(new ClassModal("CLASS 10",R.drawable.b));
        myClass.add(new ClassModal("CLASS 11",R.drawable.c));
        myClass.add(new ClassModal("CLASS 12",R.drawable.download));


    }

}

XML FILE:-

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".paper.NEET">

    <androidx.appcompat.widget.Toolbar
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:theme="@style/ThemeOverlay.AppCompat.Dark"
        android:id="@+id/toolBar"
        android:background="@color/colorPrimary"/>


    <androidx.recyclerview.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/recylcerNeet"/>



</LinearLayout>