P38.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">

    <fragment
        android:id="@+id/fragment_1"
        class="com.example.two.FragmentOne"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintHeight_default="percent"
        app:layout_constraintHeight_percent=".50"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <fragment
        android:id="@+id/fragment_2"
        class="com.example.two.FragmentTwo"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintHeight_default="percent"
        app:layout_constraintHeight_percent=".50"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/fragment_1" />


</androidx.constraintlayout.widget.ConstraintLayout>