Post 77: Percentage vertical layout

Percentagelayout is deprecated in Android, but you can achieve the same results with LinearLayout:

<?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">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:weightSum="100"
        android:orientation="vertical"
        >

        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_weight="40"
            android:orientation="vertical">
            <Button
                android:id="@+id/btnPlayer2"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:text="Button" />

        </LinearLayout>

        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_weight="20"
            android:orientation="vertical">
            <Button
                android:id="@+id/btnStart"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:text="Button" />

        </LinearLayout>

        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_weight="40"
            android:orientation="vertical">

            <Button
                android:id="@+id/btnPlayer1"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:text="Button" />

        </LinearLayout>

    </LinearLayout>

</androidx.constraintlayout.widget.ConstraintLayout>