packages/SystemUI/res/layout/auth_biometric_contents.xml

<!--
  ~ Copyright (C) 2019 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">

    <TextView
        android:id="@+id/title"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="@integer/biometric_dialog_text_gravity"
        style="@style/TextAppearance.AuthCredential.Title"/>

    <TextView
        android:id="@+id/subtitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="@integer/biometric_dialog_text_gravity"
        style="@style/TextAppearance.AuthCredential.Subtitle"/>

    <TextView
        android:id="@+id/description"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="@integer/biometric_dialog_text_gravity"
        style="@style/TextAppearance.AuthCredential.Description"/>

    <Space android:id="@+id/space_above_icon"
        android:layout_width="match_parent"
        android:layout_height="48dp" />

    <FrameLayout
        android:id="@+id/biometric_icon_frame"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal">

        <ImageView
            android:id="@+id/biometric_icon"
            android:layout_width="@dimen/biometric_dialog_biometric_icon_size"
            android:layout_height="@dimen/biometric_dialog_biometric_icon_size"
            android:layout_gravity="center"
            android:contentDescription="@null"
            android:scaleType="fitXY" />

    </FrameLayout>

    <!-- For sensors such as UDFPS, this view is used during custom measurement/layout to add extra
         padding so that the biometric icon is always in the right physical position. -->
    <Space android:id="@+id/space_below_icon"
        android:layout_width="match_parent"
        android:layout_height="12dp" />

    <TextView
        android:id="@+id/indicator"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingHorizontal="24dp"
        android:textSize="12sp"
        android:gravity="center_horizontal"
        android:accessibilityLiveRegion="polite"
        android:singleLine="true"
        android:ellipsize="marquee"
        android:textColor="@color/biometric_dialog_gray"/>

    <LinearLayout
        android:id="@+id/button_bar"
        android:layout_width="match_parent"
        android:layout_height="88dp"
        style="?android:attr/buttonBarStyle"
        android:orientation="horizontal"
        android:paddingTop="24dp">

        <Space android:id="@+id/leftSpacer"
            android:layout_width="8dp"
            android:layout_height="match_parent"
            android:visibility="visible" />

        <!-- Negative Button, reserved for app -->
        <Button android:id="@+id/button_negative"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            style="@*android:style/Widget.DeviceDefault.Button.Borderless.Colored"
            android:layout_gravity="center_vertical"
            android:ellipsize="end"
            android:maxLines="2"
            android:maxWidth="@dimen/biometric_dialog_button_negative_max_width"/>
        <!-- Cancel Button, replaces negative button when biometric is accepted -->
        <Button android:id="@+id/button_cancel"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            style="@*android:style/Widget.DeviceDefault.Button.Borderless.Colored"
            android:layout_gravity="center_vertical"
            android:maxWidth="@dimen/biometric_dialog_button_negative_max_width"
            android:text="@string/cancel"
            android:visibility="gone"/>
        <!-- "Use Credential" Button, replaces if device credential is allowed -->
        <Button android:id="@+id/button_use_credential"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            style="@*android:style/Widget.DeviceDefault.Button.Borderless.Colored"
            android:layout_gravity="center_vertical"
            android:maxWidth="@dimen/biometric_dialog_button_negative_max_width"
            android:visibility="gone"/>

        <Space android:id="@+id/middleSpacer"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:visibility="visible"/>

        <!-- Positive Button -->
        <Button android:id="@+id/button_confirm"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            style="@*android:style/Widget.DeviceDefault.Button.Colored"
            android:layout_gravity="center_vertical"
            android:ellipsize="end"
            android:maxLines="2"
            android:maxWidth="@dimen/biometric_dialog_button_positive_max_width"
            android:text="@string/biometric_dialog_confirm"
            android:visibility="gone"/>
        <!-- Try Again Button -->
        <Button android:id="@+id/button_try_again"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            style="@*android:style/Widget.DeviceDefault.Button.Colored"
            android:layout_gravity="center_vertical"
            android:ellipsize="end"
            android:maxLines="2"
            android:maxWidth="@dimen/biometric_dialog_button_positive_max_width"
            android:text="@string/biometric_dialog_try_again"
            android:visibility="gone"/>

        <Space android:id="@+id/rightSpacer"
            android:layout_width="8dp"
            android:layout_height="match_parent"
            android:visibility="visible" />
    </LinearLayout>

</merge>