prebuilts/gradle/ConfirmDeviceCredentials/Application/src/main/res/layout/activity_main.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
  -->
<ScrollView
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
                  android:layout_width="match_parent"
                  android:layout_height="wrap_content"
                  android:orientation="vertical">

        <ImageView
                android:layout_width="150dp"
                android:layout_height="150dp"
                android:layout_marginTop="32dp"
                android:layout_marginBottom="32dp"
                android:layout_gravity="center_horizontal"
                android:scaleType="fitCenter"
                android:src="@drawable/android_robot"/>

        <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="8dp"
                android:layout_marginStart="8dp"
                android:layout_marginEnd="8dp"
                android:orientation="vertical"
                android:background="@drawable/card"
                android:elevation="4dp"
                android:paddingTop="16dp"
                android:paddingBottom="16dp"
                android:paddingStart="16dp"
                android:paddingEnd="16dp">

            <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textAppearance="@android:style/TextAppearance.Material.Headline"
                    android:text="@string/item_title"/>

            <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textAppearance="@android:style/TextAppearance.Material.Body2"
                    android:textColor="?android:attr/colorAccent"
                    android:text="@string/item_price"/>

            <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="16dp"
                    android:textAppearance="@android:style/TextAppearance.Material.Body1"
                    android:textColor="?android:attr/textColorSecondary"
                    android:text="@string/item_description"/>

        </LinearLayout>
        <Button style="@android:style/Widget.Material.Button.Colored"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="8dp"
                android:layout_marginEnd="4dp"
                android:layout_gravity="end"
                android:textColor="?android:attr/textColorPrimaryInverse"
                android:text="@string/purchase"
                android:id="@+id/purchase_button"
                android:layout_alignParentEnd="true"/>

        <TextView
                android:id="@+id/confirmation_message"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="16dp"
                android:paddingStart="16dp"
                android:paddingEnd="16dp"
                android:textAppearance="@android:style/TextAppearance.Material.Body2"
                android:textColor="?android:attr/colorAccent"
                android:text="@string/purchase_done"
                android:visibility="gone"/>

        <TextView
                android:id="@+id/already_has_valid_device_credential_message"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="16dp"
                android:paddingStart="16dp"
                android:paddingEnd="16dp"
                android:textAppearance="@android:style/TextAppearance.Material.Body2"
                android:textColor="?android:attr/colorAccent"
                android:text="@string/already_confirmed_device_credentials_within_last_x_seconds"
                android:visibility="gone"/>
    </LinearLayout>
</ScrollView>