packages/SystemUI/res/layout/navigation_bar.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
/* apps/common/assets/default/default/skins/StatusBar.xml
**
** Copyright 2011, 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.
*/
-->

<com.android.systemui.statusbar.phone.NavigationBarView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:systemui="http://schemas.android.com/apk/res/com.android.systemui"
    android:layout_height="match_parent"
    android:layout_width="match_parent"
    >

    <FrameLayout
        android:id="@+id/background"
        android:layout_height="match_parent"
        android:layout_width="match_parent"
        android:background="#FF000000"
        >

        <LinearLayout android:id="@+id/rot0"
            android:layout_height="match_parent"
            android:layout_width="match_parent"
            android:paddingLeft="8dip"
            android:paddingRight="8dip"
            android:orientation="horizontal"
            >

            <!-- navigation controls -->
            <com.android.systemui.statusbar.policy.KeyButtonView android:id="@+id/back"
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:src="@drawable/ic_sysbar_back"
                systemui:keyCode="4"
                android:layout_weight="1"
                />
            <com.android.systemui.statusbar.policy.KeyButtonView android:id="@+id/home"
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:src="@drawable/ic_sysbar_home"
                systemui:keyCode="3"
                android:layout_weight="1"
                />
            <com.android.systemui.statusbar.policy.KeyButtonView android:id="@+id/menu"
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:src="@drawable/ic_sysbar_menu"
                systemui:keyCode="82"
                android:layout_weight="1"
                />
        </LinearLayout>

        <LinearLayout android:id="@+id/rot90"
            android:layout_height="match_parent"
            android:layout_width="match_parent"
            android:orientation="vertical"
            android:visibility="gone"
            >

            <!-- navigation controls -->
            <com.android.systemui.statusbar.policy.KeyButtonView android:id="@+id/menu"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:src="@drawable/ic_sysbar_menu"
                systemui:keyCode="82"
                android:layout_weight="1"
                />
            <com.android.systemui.statusbar.policy.KeyButtonView android:id="@+id/home"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:src="@drawable/ic_sysbar_home"
                systemui:keyCode="3"
                android:layout_weight="1"
                />
            <com.android.systemui.statusbar.policy.KeyButtonView android:id="@+id/back"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:src="@drawable/ic_sysbar_back"
                systemui:keyCode="4"
                android:layout_weight="1"
                />
        </LinearLayout>

        <LinearLayout android:id="@+id/rot270"
            android:layout_height="match_parent"
            android:layout_width="match_parent"
            android:orientation="vertical"
            android:visibility="gone"
            >

            <!-- navigation controls -->
            <com.android.systemui.statusbar.policy.KeyButtonView android:id="@+id/back"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:src="@drawable/ic_sysbar_back"
                systemui:keyCode="4"
                android:layout_weight="1"
                />
            <com.android.systemui.statusbar.policy.KeyButtonView android:id="@+id/home"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:src="@drawable/ic_sysbar_home"
                systemui:keyCode="3"
                android:layout_weight="1"
                />
            <com.android.systemui.statusbar.policy.KeyButtonView android:id="@+id/menu"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:src="@drawable/ic_sysbar_menu"
                systemui:keyCode="82"
                android:layout_weight="1"
                />
        </LinearLayout>
    
    </FrameLayout>
</com.android.systemui.statusbar.phone.NavigationBarView>