res/layout/activity_call_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
Copyright (C) 2004-2012 Savoir-Faire Linux Inc.                     
                                                                    
Author: Adrien Beraud <adrien.beraud@gmail.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, write to the Free Software         
 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.          
                                                                    
Additional permission under GNU GPL version 3 section 7:            
                                                                    
If you modify this program, or any covered work, by linking or      
combining it with the OpenSSL project's OpenSSL library (or a       
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-->

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/CallActivityLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center_horizontal"
    android:orientation="vertical" >

    <!-- 
    <Button
        android:id="@+id/buttonanswer"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Answer Up" />

    <Button
        android:id="@+id/buttonhangup"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Hang Up" />

    <Button
        android:id="@+id/buttonhold"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Hold" />

    <Button
        android:id="@+id/buttonunhold"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Unhold" /> -->

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

</LinearLayout>