res/layout/play_controls_button.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Copyright (C) 2015 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.
  -->

<merge xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- Need to use additional ImageView to set the scaleType to "centerCrop"
         If we don't use this ImageView and set the drawable to the icon,
         the background will be an ellipse, not a circle  -->
    <ImageView android:id="@+id/button"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:focusable="true"
        android:scaleType="centerCrop"
        android:src="@drawable/play_controls_button_background" />
    <ImageView
        android:id="@+id/icon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center" />
    <TextView
        android:id="@+id/label"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:visibility="gone"
        style="@style/TextAppearance.Leanback.PlaybackControlLabel" />
</merge>