packages/SystemUI/res/layout/screen_pinning_request_buttons.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
/**
 * Copyright (c) 2014, 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.
 */
-->
<!--
     This layout matches the structure of navigation_bar.xml and will need
     to be kept up to sync with changes there.
     On sw600dp, dimensions are changed to be large enough such that the
     empty views between the buttons is reduced to nothing, if (nav bar)
     sw600dp layout is changed then this will likely have to be adjusted
     and possibly need a sw600dp specific one.
-->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/screen_pinning_buttons"
    android:layout_width="match_parent"
    android:layout_height="@dimen/screen_pinning_request_button_height"
    android:background="?android:attr/colorAccent">

    <View
        android:layout_width="@dimen/screen_pinning_request_side_width"
        android:layout_height="match_parent"
        android:layout_weight="0"
        android:visibility="invisible" />

    <FrameLayout
        android:id="@+id/screen_pinning_back_group"
        android:layout_width="@dimen/screen_pinning_request_button_width"
        android:layout_height="@dimen/screen_pinning_request_button_height"
        android:layout_weight="0"
        android:paddingStart="@dimen/screen_pinning_request_frame_padding"
        android:paddingEnd="@dimen/screen_pinning_request_frame_padding"
        android:theme="@*android:style/ThemeOverlay.DeviceDefault.Accent">

        <ImageView
            android:id="@+id/screen_pinning_back_bg_light"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:scaleType="matrix"
            android:src="@drawable/screen_pinning_light_bg_circ" />

        <ImageView
            android:id="@+id/screen_pinning_back_bg"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:paddingEnd="@dimen/screen_pinning_request_inner_padding"
            android:paddingStart="@dimen/screen_pinning_request_inner_padding"
            android:paddingTop="@dimen/screen_pinning_request_inner_padding"
            android:scaleType="matrix"
            android:src="@drawable/screen_pinning_bg_circ" />

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:paddingEnd="@dimen/screen_pinning_request_nav_side_padding"
            android:paddingStart="@dimen/screen_pinning_request_nav_side_padding"
            android:paddingTop="@dimen/screen_pinning_request_nav_icon_padding"
            android:scaleType="center"
            android:src="@drawable/ic_sysbar_back" />
    </FrameLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:visibility="invisible" />

    <FrameLayout
        android:id="@+id/screen_pinning_home_group"
        android:layout_width="@dimen/screen_pinning_request_button_width"
        android:layout_height="@dimen/screen_pinning_request_button_height"
        android:layout_weight="0"
        android:paddingStart="@dimen/screen_pinning_request_frame_padding"
        android:paddingEnd="@dimen/screen_pinning_request_frame_padding" >

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:paddingEnd="@dimen/screen_pinning_request_nav_side_padding"
            android:paddingStart="@dimen/screen_pinning_request_nav_side_padding"
            android:paddingTop="@dimen/screen_pinning_request_nav_icon_padding"
            android:scaleType="center"
            android:src="@drawable/ic_sysbar_home" />
    </FrameLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:visibility="invisible" />

    <FrameLayout
        android:id="@+id/screen_pinning_recents_group"
        android:layout_width="@dimen/screen_pinning_request_button_width"
        android:layout_height="@dimen/screen_pinning_request_button_height"
        android:layout_weight="0"
        android:paddingStart="@dimen/screen_pinning_request_frame_padding"
        android:paddingEnd="@dimen/screen_pinning_request_frame_padding" >

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:paddingEnd="@dimen/screen_pinning_request_nav_side_padding"
            android:paddingStart="@dimen/screen_pinning_request_nav_side_padding"
            android:paddingTop="@dimen/screen_pinning_request_nav_icon_padding"
            android:scaleType="center"
            android:src="@drawable/ic_sysbar_recent" />
    </FrameLayout>

    <View
        android:layout_width="@dimen/screen_pinning_request_side_width"
        android:layout_height="match_parent"
        android:layout_weight="0"
        android:visibility="invisible" />

</LinearLayout>