layout_dummy_card.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:paddingTop="8dp"
    android:layout_height="match_parent">


    <android.support.v7.widget.CardView
        xmlns:card_view="http://schemas.android.com/apk/res-auto"
        android:id="@+id/card_view"
        android:layout_gravity="center"
        android:layout_width="match_parent"
        android:layout_height="100dp"
        card_view:cardCornerRadius="4dp">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:padding="16dp"
            >

            <TextView
                android:id="@+id/dummy_text"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:textSize="24sp"
                android:layout_centerInParent="true"
                android:textColor="@android:color/black"
                />

        </RelativeLayout>

    </android.support.v7.widget.CardView>


</LinearLayout>