title: CardView custom background
body: <p>I try to add custom background in my CardView.This is my source</p>
  
  <pre><code>&lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  android:id="@+id/item_container"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:background="#ff00"
  android:orientation="vertical"&gt;
  
  
  &lt;android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      card_view:cardCornerRadius="12dp"
      card_view:cardElevation="12dp"
      card_view:cardPreventCornerOverlap="false"
      card_view:contentPadding="0dp"
      android:layout_margin="16dp"
      &gt;
  
      &lt;LinearLayout
          android:layout_width="match_parent"
          android:layout_height="80dp"
          android:orientation="vertical"&gt;
          &lt;RelativeLayout
              android:layout_width="match_parent"
              android:layout_height="40dp"
              android:background="#cccccc"&gt;
          &lt;/RelativeLayout&gt;
      &lt;/LinearLayout&gt;
  &lt;/android.support.v7.widget.CardView&gt;
  </code></pre>
  
  <p>
  <a href="https://i.stack.imgur.com/LnGJL.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/LnGJL.png" alt="And this is a result"></a></p>
  
  <p>As you can see into Cardview i have LinearLayout and RelativieLayout.RelativeLayout's background color is #cccccc,but cornerradius and elevetion not working with custom background color.(please see my picture)
  How i can solve my problem?</p>