InCallUI/res/layout/answer_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Copyright (C) 2013 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.incallui.GlowPadWrapper
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:dc="http://schemas.android.com/apk/res-auto"
        android:id="@+id/glow_pad_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:focusable="true"
        android:layout_centerHorizontal="true"
        android:gravity="center"
        android:background="@color/glowpad_background_color"
        android:layout_marginBottom="@dimen/glowpadview_margin_bottom"

        dc:targetDrawables="@array/incoming_call_widget_audio_with_sms_targets"
        dc:targetDescriptions="@array/incoming_call_widget_audio_with_sms_target_descriptions"
        dc:directionDescriptions="@array/incoming_call_widget_audio_with_sms_direction_descriptions"
        dc:handleDrawable="@drawable/ic_incall_audio_handle"
        dc:outerRingDrawable="@drawable/ic_lockscreen_outerring"
        dc:outerRadius="@dimen/glowpadview_target_placement_radius"
        dc:innerRadius="@dimen/glowpadview_inner_radius"
        dc:snapMargin="@dimen/glowpadview_snap_margin"
        dc:feedbackCount="1"
        dc:vibrationDuration="20"
        dc:glowRadius="@dimen/glowpadview_glow_radius"
        dc:pointDrawable="@drawable/ic_lockscreen_glowdot"
        dc:allowScaling="true" />