Firebase RecyclerView in Android Studio

in item_common.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    app:cardCornerRadius="6dp"
    android:elevation="6dp"
    app:cardUseCompatPadding="true">

    <RelativeLayout
        android:id="@+id/parent_layout"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#8DFA91"
        android:padding="15dp">


        <TextView
            android:id="@+id/txt_common_title_item"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="TextView"
            android:textColor="@color/black"
            android:textSize="16sp"
            android:textStyle="bold" />

        <TextView
            android:id="@+id/txt_common_sex_item"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@+id/txt_common_title_item"
            android:text="TextView"
            android:textColor="@color/black" />

        <TextView
            android:id="@+id/txt_pt_id_item"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@+id/txt_common_sex_item"
            android:text="TextView"
            android:visibility="invisible" />
    </RelativeLayout>

</androidx.cardview.widget.CardView>

in activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
    tools:context=".MainActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rv1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="32dp"
        android:layout_marginTop="32dp"
        android:layout_marginEnd="32dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

in MainActivity.java

public class MainActivity extends AppCompatActivity {

    RecyclerView recyclerView;
    CommonAdapter commonAdapter;

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

        recyclerView = findViewById(R.id.rv1);

        recyclerView.setLayoutManager(new GridLayoutManager(this, 2, LinearLayoutManager.VERTICAL, false));

        FirebaseRecyclerOptions<CommonModel> options = new FirebaseRecyclerOptions.Builder<CommonModel>()
                .setQuery(FirebaseDatabase.getInstance().getReference().child("SiddhaMedicine").child("Surgery"), CommonModel.class)
                .build();

        commonAdapter = new CommonAdapter(options, this);
        recyclerView.setAdapter(commonAdapter);
    }

    @Override
    protected void onStart() {
        super.onStart();
        commonAdapter.startListening();
    }

    @Override
    protected void onStop() {
        super.onStop();
        commonAdapter.stopListening();
    }
}

in CommonModel.java

public class CommonModel {

    String Id, Title, Body;

    public CommonModel() {
    }

    public CommonModel(String id, String title, String body) {
        Id = id;
        Title = title;
        Body = body;
    }

    public String getId() {
        return Id;
    }

    public void setId(String id) {
        Id = id;
    }

    public String getTitle() {
        return Title;
    }

    public void setTitle(String title) {
        Title = title;
    }

    public String getBody() {
        return Body;
    }

    public void setBody(String body) {
        Body = body;
    }
}

in CommonAdapter.java

public class CommonAdapter extends FirebaseRecyclerAdapter<CommonModel, CommonAdapter.myViewHolder> {

    private Context mContext;

    /**
     * Initialize a {@link RecyclerView.Adapter} that listens to a Firebase query. See
     * {@link FirebaseRecyclerOptions} for configuration options.
     *
     * @param options
     */
    public CommonAdapter(@NonNull FirebaseRecyclerOptions<CommonModel> options, Context context) {
        super(options);
        mContext = context;
    }

    @Override
    protected void onBindViewHolder(@NonNull CommonAdapter.myViewHolder holder, int position, @NonNull CommonModel model) {

        holder.cName.setText(model.getTitle());
        holder.cSex.setText(model.getId());

        holder.relativeLayout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(mContext, model.getTitle(), Toast.LENGTH_SHORT).show();
                Intent intent = new Intent(mContext, BodyActivity.class);
                intent.putExtra("bId", model.getId());
                mContext.startActivity(intent);
            }
        });

    }

    @NonNull
    @Override
    public CommonAdapter.myViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_common,parent,false);
        return new  CommonAdapter.myViewHolder(view);
    }

    public class myViewHolder extends RecyclerView.ViewHolder {

        TextView cName, cSex;
        RelativeLayout relativeLayout;

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

            cName = (TextView) itemView.findViewById(R.id.txt_common_title_item);
            cSex = (TextView) itemView.findViewById(R.id.txt_common_sex_item);
            relativeLayout = (RelativeLayout) itemView.findViewById(R.id.parent_layout);
        }
    }
}

in build.gradle(:app)

implementation 'androidx.cardview:cardview:1.0.0'
implementation 'com.firebaseui:firebase-ui-database:7.1.1'
implementation "androidx.recyclerview:recyclerview:1.2.1"