nextcloud-talk-android/app/src/main/res/layout/activity_magic_call.xml

<?xml version="1.0" encoding="utf-8"?><!--
  ~ Nextcloud Talk application
  ~
  ~ @author Mario Danic
  ~ Copyright (C) 2017-2018 Mario Danic <mario@lovelyhq.com>
  ~
  ~ This program is free software: you can redistribute it and/or modify
  ~ it under the terms of the GNU General Public License as published by
  ~ the Free Software Foundation, either version 3 of the License, or
  ~ at your option) any later version.
  ~
  ~ This program is distributed in the hope that it will be useful,
  ~ but WITHOUT ANY WARRANTY; without even the implied warranty of
  ~ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  ~ GNU General Public License for more details.
  ~
  ~ You should have received a copy of the GNU General Public License
  ~ along with this program.  If not, see <http://www.gnu.org/licenses/>.
  -->

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context=".activities.MagicCallActivity">

    <com.bluelinelabs.conductor.ChangeHandlerFrameLayout
        android:id="@+id/controller_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <com.bluelinelabs.conductor.ChangeHandlerFrameLayout
        android:id="@+id/chatControllerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="gone" />

</RelativeLayout>