wearable/wear/WearMessagingApp/Wearable/src/main/res/layout/activity_signin.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Copyright 2017 Google Inc.
  ~
  ~ 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.
  -->

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/blue_500"
    android:gravity="center"
    android:orientation="vertical"
    tools:context=".SignInActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        style="@style/LogoText"
        android:text="@string/wear_messaging_app" />

    <com.google.android.gms.common.SignInButton
        android:id="@+id/sign_in_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:buttonSize="standard"
        app:colorScheme="auto"
        />

</LinearLayout>