res/layout/video_call_views.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
  -->

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextureView
        android:id="@+id/incomingVideo"
        android:layout_gravity="center"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
    <!-- The width and height are replaced at runtime based on the selected camera. -->
    <FrameLayout
        android:id="@+id/previewVideoContainer"
        android:layout_width="70dp"
        android:layout_height="120dp"
        android:layout_gravity="bottom|right"
        android:layout_margin="@dimen/video_preview_margin" >

        <!-- The video preview surface, where the user's outgoing video is shown. -->
        <TextureView
            android:id="@+id/previewVideo"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

        <!-- The user's profile photo, shown when the user's camera is shut off. -->
        <ImageView
            android:id="@+id/previewProfilePhoto"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:scaleType="centerInside"
            android:adjustViewBounds="false"
            android:contentDescription="@string/profile_photo_description"
            android:background="@android:color/black"
            android:visibility="gone" />

        <!-- The "camera off" icon, shown when the user's camera is shut off. -->
        <ImageView
            android:id="@+id/previewCameraOff"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom|right"
            android:layout_marginEnd="10dp"
            android:layout_marginBottom="10dp"
            android:scaleType="centerCrop"
            android:contentDescription="@string/camera_off_description"
            android:src="@drawable/ic_toolbar_video_off"
            android:visibility="gone" />
    </FrameLayout>
</FrameLayout>