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"
    android:orientation="vertical"
    tools:context=".MainActivity">
    <ImageView
        android:scaleType="centerCrop"
        android:src="@drawable/casino"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
    </ImageView>

    <Button
        android:onClick="toHighAndLow"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="50dp"
        android:background="@drawable/to_high_low"
        android:drawableRight="@drawable/daiya"
        android:gravity="center"
        android:paddingLeft="20dp"
        android:text="High ＆ Low"
        android:textSize="20dp"
        app:layout_constraintVertical_bias="0.1"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>