what.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">
    <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/main_view"
            android:scrollbars="vertical"
            android:layout_width="411dp"
            android:layout_height="850dp"
            app:layout_constraintStart_toStartOf="parent" app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintTop_toTopOf="parent" app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintHorizontal_bias="0.0" app:layout_constraintVertical_bias="0.0"/>
</androidx.constraintlayout.widget.ConstraintLayout>