java 簡単なrecyclerviewについて

前提・実現したいこと

recyclerviewで画面に一行ずつしか表示されず
まとまって表示されません
いろいろと試したのですがうまくいきません
回答してくれたら幸いです

エラーは特に出ていません

発生している問題・エラーメッセじ

特になし

該当のソースコード

Java

☆彡MainActivity:code➡
package com.example.recyclerview1;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.os.Bundle;

import com.google.android.gms.tasks.OnSuccessListener;
import com.google.firebase.firestore.DocumentSnapshot;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.QuerySnapshot;

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

public class MainActivity extends AppCompatActivity {

RecyclerView recview;
ArrayList<model> datalist;
FirebaseFirestore db;
myadapter myadapter;

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

    recview=(RecyclerView)findViewById(R.id.recview);
    recview.setLayoutManager(new LinearLayoutManager(this));
datalist=new ArrayList<>();

myadapter=new myadapter(datalist);
recview.setAdapter(myadapter);

db=FirebaseFirestore.getInstance();
db.collection("students").get()
        .addOnSuccessListener
                (new OnSuccessListener<QuerySnapshot>() {
                    @Override
                    public void onSuccess(QuerySnapshot queryDocumentSnapshots) {
                        List<DocumentSnapshot>
                                list=queryDocumentSnapshots.getDocuments();
                        for (DocumentSnapshot d:list){
                            model obj=d.toObject(model.class);
                            datalist.add(obj);

                        }

                       myadapter.notifyDataSetChanged();
                    }
                });
}

☆彡model:code➡
package com.example.recyclerview1;

public class model {

String name, email;

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

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getEmail() {
    return email;
}

public void setEmail(String email) {
    this.email = email;
}

}

☆彡myadapter:code➡

package com.example.recyclerview1;

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.ArrayList;

public class myadapter extends
RecyclerView.Adapter<myadapter.myviewholder>
{

ArrayList<model> datalist;

public myadapter(ArrayList<model> datalist) {
    this.datalist = datalist;
}

@NonNull
@Override
public myviewholder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View view= LayoutInflater.from(parent.getContext())
            .inflate(R.layout.my_row, parent, false);
return  new myviewholder(view);

}

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

    holder.t1.setText(datalist.get(position).getName());
    holder.t2.setText(datalist.get(position).getEmail());

}

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

class myviewholder extends RecyclerView.ViewHolder{

TextView t1, t2;
public myviewholder(@NonNull View itemView) {

    super(itemView);

t1=itemView.findViewById(R.id.t1);
    t2=itemView.findViewById(R.id.t2);

}

}

☆彡acrivity_main.xml:code➡

<?xml version="1.0" encoding="utf-8"?>

<androidx.appcompat.widget.LinearLayoutCompat 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:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/recview"/>

</androidx.appcompat.widget.LinearLayoutCompat>

☆彡my_row➡

<?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:orientation="vertical"
android:layout_margin="10dp"
android:layout_height="match_parent">

<androidx.cardview.widget.CardView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintBottom_toBottomOf="parent">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="16dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent">

            <TextView
                android:id="@+id/t1"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_centerHorizontal="true"
                android:text="Name"
                android:textColor="#000"
                android:textSize="25dp"
                android:textStyle="bold" />

            <TextView
                android:id="@+id/t2"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/t1"
                android:layout_centerHorizontal="true"
                android:text="email"
                android:textSize="23dp" />
        </RelativeLayout>
    </androidx.constraintlayout.widget.ConstraintLayout>

</androidx.cardview.widget.CardView>

</androidx.constraintlayout.widget.ConstraintLayout>