core/res/res/layout/keyguard_navigation.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
**
** Copyright 2008, 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.
*/
-->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="left">

    <LinearLayout
        android:id="@+id/keyguard_click_area"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        style="?android:attr/buttonBarButtonStyle"
        android:padding="10dip"
        android:clickable="true">

        <TextView
            android:layout_width="20dip"
            android:layout_height="wrap_content"
            android:textSize="28dp"
            android:text="@string/kg_temp_back_string" />

        <!-- message area for security screen -->
        <TextView
            android:id="@+id/keyguard_message_area"
            android:layout_width="0dip"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:singleLine="true"
            android:ellipsize="marquee"
            android:layout_marginEnd="6dip"
            android:layout_marginStart="6dip"
            android:textAppearance="?android:attr/textAppearanceMedium"/>

    </LinearLayout>

</LinearLayout>