packages/SystemUI/res/layout/battery_low.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
/* //device/apps/common/res/layout/keyguard.xml
**
** Copyright 2007, 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:id="@+id/padding"
    android:orientation="vertical"
    android:gravity="center"
    android:padding="16dp"
    >

    <TextView android:id="@+id/subtitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="18sp"
        android:textColor="#ffffffff"
        android:gravity="left"
        android:text="@string/battery_low_subtitle"
        />
    
    <TextView android:id="@+id/level_percent"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="18sp"
        android:textColor="#ffffffff"
        android:gravity="left"
        android:paddingBottom="16dp"
        />

    <ImageView android:id="@+id/image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/battery_low_battery"
        />

</LinearLayout>