apps/OboeTester/app/src/main/res/layout/activity_recorder.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.google.sample.oboe.manualtest.RecorderActivity">

    <com.google.sample.oboe.manualtest.StreamConfigurationView
        android:id="@+id/streamConfiguration"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:orientation="horizontal" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:id="@+id/button_start_recording"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:onClick="onStartRecording"
            android:text="@string/recordAudio" />

        <Button
            android:id="@+id/button_stop_record_play"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:onClick="onStopRecordPlay"
            android:text="@string/stopAudio" />

        <Button
            android:id="@+id/button_start_playback"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:onClick="onStartPlayback"
            android:text="@string/playAudio" />

    </LinearLayout>

    <TextView
        android:id="@+id/statusView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:lines="3"
        android:text="@string/init_status" />

    <TextView
        android:id="@+id/volumeText0"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="\?" />

    <com.google.sample.oboe.manualtest.VolumeBarView
        android:id="@+id/volumeBar0"
        android:layout_width="fill_parent"
        android:layout_height="20dp" />

    <TextView
        android:id="@+id/volumeText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="\?" />

    <com.google.sample.oboe.manualtest.VolumeBarView
        android:id="@+id/volumeBar1"
        android:layout_width="fill_parent"
        android:layout_height="20dp" />

    <TextView
        android:id="@+id/volumeText2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="\?" />

    <com.google.sample.oboe.manualtest.VolumeBarView
        android:id="@+id/volumeBar2"
        android:layout_width="fill_parent"
        android:layout_height="20dp" />

    <TextView
        android:id="@+id/volumeText3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="\?" />

    <com.google.sample.oboe.manualtest.VolumeBarView
        android:id="@+id/volumeBar3"
        android:layout_width="fill_parent"
        android:layout_height="20dp" />

</LinearLayout>