samples/LiveEffect/src/main/res/layout-v21/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Copyright (C) 2018 The Android Open Source Project
  ~
  ~ Licensed under the Apache License, Version 2.0 (the "License");
  ~ you may not use this file except in compliance with the License.
  ~ You may obtain a copy of the License at
  ~
  ~      http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing, software
  ~ distributed under the License is distributed on an "AS IS" BASIS,
  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ~ See the License for the specific language governing permissions and
  ~ limitations under the License.
  -->
<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="com.google.oboe.samples.liveEffect.MainActivity"
    tools:layout_editor_absoluteY="81dp">

    <RadioGroup xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/apiSelectionGroup"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/activity_horizontal_margin"
        android:layout_marginLeft="@dimen/activity_horizontal_margin"
        android:layout_marginTop="@dimen/activity_vertical_margin"
        android:orientation="horizontal"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <TextView
            android:id="@+id/apiTextView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/apiSelection" />

        <RadioButton
            android:id="@+id/aaudioButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="16dp"
            android:layout_marginLeft="16dp"
            android:text="@string/aaudio" />

        <RadioButton
            android:id="@+id/slesButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="16dp"
            android:layout_marginLeft="16dp"
            android:text="@string/sles" />
    </RadioGroup>

    <TextView
        android:id="@+id/recDeviceLabel"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/activity_horizontal_margin"
        android:layout_marginLeft="@dimen/activity_horizontal_margin"
        android:layout_marginTop="@dimen/activity_vertical_margin"
        android:text="@string/recording_device"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/apiSelectionGroup"/>

    <com.google.oboe.samples.audio_device.AudioDeviceSpinner
        android:id="@+id/recording_devices_spinner"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/activity_horizontal_margin"
        android:layout_marginLeft="@dimen/activity_horizontal_margin"
        android:layout_marginTop="0dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/recDeviceLabel" />

    <TextView
        android:id="@+id/playDeviceLabel"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/activity_horizontal_margin"
        android:layout_marginLeft="@dimen/activity_horizontal_margin"
        android:layout_marginTop="@dimen/activity_vertical_margin"
        android:text="@string/playback_device"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/recording_devices_spinner" />

    <com.google.oboe.samples.audio_device.AudioDeviceSpinner
        android:id="@+id/playback_devices_spinner"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/activity_horizontal_margin"
        android:layout_marginLeft="@dimen/activity_horizontal_margin"
        android:layout_marginTop="0dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/playDeviceLabel" />

    <Button
        android:id="@+id/button_toggle_effect"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="72dp"
        android:gravity="center"
        android:text="@string/start_effect"
        android:textAllCaps="false"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.53"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/playback_devices_spinner" />

    <TextView
        android:id="@+id/status_view_text"
        android:layout_width="0dp"
        android:layout_height="60dp"
        android:layout_marginStart="@dimen/activity_horizontal_margin"
        android:layout_marginEnd="@dimen/activity_horizontal_margin"
        android:layout_marginTop="@dimen/activity_vertical_group_margin"
        android:lines="6"
        android:text="@string/status_warning"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button_toggle_effect"
        app:layout_constraintBottom_toBottomOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>