ThreeGames/app/src/main/res/layout/activity_alert.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <TextView
        android:id="@+id/label"
        android:textColor="#000"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toTopOf="@id/sure"
        app:layout_constraintVertical_chainStyle="packed"
        android:textSize="25sp"
        android:gravity="center"
        android:textStyle="bold" />
    <Button
        android:id="@+id/sure"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="確定"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        android:layout_marginTop="20dp"
        app:layout_constraintTop_toBottomOf="@id/label"
        app:layout_constraintBottom_toBottomOf="parent"
        android:background="@android:color/holo_green_light"/>

</androidx.constraintlayout.widget.ConstraintLayout>