res/layout/call_card.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
  -->

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

    <!-- The main content of the CallCard is either one or two "call info"
         blocks, depending on whether one or two lines are in use.

         The call_info blocks are stacked vertically inside a CallCard (LinearLayout),
         each with layout_weight="1".  If only one line is in use (i.e. the
         common case) then the 2nd call info will be GONE and thus the 1st one
         will expand to fill the full height of the CallCard. -->


    <!-- Primary "call card" block, for the foreground call. -->
    <include android:id="@+id/primary_call_info"
            layout="@layout/primary_call_info" />

    <!-- Secondary "Call info" block, for the background ("on hold") call. -->
    <ViewStub android:id="@+id/secondary_call_info"
            android:layout="@layout/secondary_call_info"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1" />

</LinearLayout>