baresip-studio/app/src/main/res/layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<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:layout_marginBottom="10dp"
    tools:context=".MainActivity">

    <ScrollView
        android:id="@+id/scrollView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fillViewport="true" >

        <RelativeLayout
            android:id="@+id/mainActivityLayout"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:focusable="true"
            android:focusableInTouchMode="true"
            android:paddingBottom="@dimen/activity_vertical_margin"
            android:paddingLeft="@dimen/activity_horizontal_margin"
            android:paddingRight="@dimen/activity_horizontal_margin"
            android:paddingTop="@dimen/activity_vertical_margin">

            <Spinner
                android:id="@+id/AoRList"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="@android:drawable/btn_dropdown"
                android:spinnerMode="dropdown"/>

            <TextView
                android:id="@+id/callTitle"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_below="@id/AoRList"
                android:paddingTop="16dp"
                android:paddingStart="3dp"
                android:textSize="20sp"
                android:textColor="@android:color/black"
                android:text="Outgoing call to ..." >
            </TextView>

            <LinearLayout
                android:id="@+id/uriRow"
                android:orientation="horizontal"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_below="@id/callTitle" >

                <AutoCompleteTextView
                    android:id="@+id/uri"
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content"
                    android:layout_weight = "1"
                    android:inputType="textEmailAddress"
                    android:textSize="20sp"
                    android:hint="Callee" >
                    <!-- <requestFocus /> -->
                </AutoCompleteTextView>

                <ImageButton
                    android:id="@+id/securityButton"
                    android:layout_width="24dp"
                    android:layout_height="24dp"
                    android:layout_weight = "0"
                    android:layout_gravity = "center_vertical"
                    android:visibility="invisible"
                    android:contentDescription="@string/app_name" >
                </ImageButton>

            </LinearLayout>

            <ImageButton
                android:id="@+id/callButton"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@id/uriRow"
                android:padding="0dp"
                android:background="@null"
                android:src="@drawable/call_green" >
            </ImageButton>

            <ImageButton
                android:id="@+id/hangupButton"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@id/uriRow"
                android:padding="0dp"
                android:background="@null"
                android:src="@drawable/hangup"
                android:clickable="false"
                android:visibility="invisible" >
            </ImageButton>


            <ImageButton
                android:id="@+id/answerButton"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@id/uriRow"
                android:padding="0dp"
                android:background="@null"
                android:src="@drawable/call_green"
                android:clickable="false"
                android:visibility="invisible" >
            </ImageButton>

            <ImageButton
                android:id="@+id/rejectButton"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@id/uriRow"
                android:padding="0dp"
                android:background="@null"
                android:layout_marginStart="70dp"
                android:src="@drawable/hangup"
                android:clickable="false"
                android:visibility="invisible" >
            </ImageButton>

            <ImageButton
                android:id="@+id/holdButton"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@id/uriRow"
                android:padding="0dp"
                android:src="@drawable/pause"
                android:background="@null"
                android:layout_marginStart="70dp"
                android:clickable="false"
                android:visibility="invisible" >
            </ImageButton>

            <EditText
                android:id="@+id/dtmf"
                android:layout_width="@dimen/button_width"
                android:layout_height="wrap_content"
                android:layout_below="@id/uriRow"
                android:layout_marginStart="140dp"
                android:inputType="phone"
                android:textSize="20sp"
                android:hint="DTMF"
                android:visibility="invisible" >
            </EditText>

        </RelativeLayout>

    </ScrollView>

    <ImageButton
        android:id="@+id/voicemailButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@null"
        android:src="@drawable/voicemail"
        android:layout_toStartOf="@id/contactsButton"
        android:layout_marginEnd="10dp"
        android:layout_alignParentBottom="true"
        android:visibility="invisible" >
    </ImageButton>

    <ImageButton
        android:id="@+id/contactsButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@null"
        android:src="@drawable/contacts"
        android:layout_toStartOf="@id/messagesButton"
        android:layout_marginEnd="10dp"
        android:layout_alignParentBottom="true" >
    </ImageButton>

    <ImageButton
        android:id="@+id/messagesButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@null"
        android:src="@drawable/messages"
        android:layout_toStartOf="@id/callsButton"
        android:layout_marginEnd="10dp"
        android:layout_alignParentBottom="true" >
    </ImageButton>

    <ImageButton
        android:id="@+id/callsButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="0dp"
        android:background="@null"
        android:src="@drawable/calls"
        android:layout_marginEnd="10dp"
        android:layout_alignParentBottom="true"
        android:layout_alignParentEnd="true" >
    </ImageButton>

</RelativeLayout>