res/layout/tare_dropdown_page.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=".development.tare.DropdownActivity">
  <com.android.settingslib.widget.settingsspinner.SettingsSpinner
      android:id="@+id/spinner"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      app:layout_constraintEnd_toEndOf="parent"
      app:layout_constraintStart_toStartOf="parent"
      app:layout_constraintTop_toTopOf="parent"
      android:theme="@style/Widget.PopupWindow.Settings"
      android:padding="10dp" />
  <FrameLayout
      android:id="@+id/frame_layout"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      app:layout_constraintBottom_toBottomOf="parent"
      app:layout_constraintEnd_toEndOf="parent"
      app:layout_constraintStart_toStartOf="parent"
      app:layout_constraintTop_toBottomOf="@+id/spinner"
      app:layout_constraintVertical_bias="0" />
</androidx.constraintlayout.widget.ConstraintLayout>