title: Round only top corner of cardview
body: <p>I want to corner only the top of a cardview.</p>
  
  <p>I used below property and it is rounding all the corner.</p>
  
  <p>I want to show an overlap of all cards</p>
  
  <pre><code>card_view:cardCornerRadius="4dp"
  </code></pre>
  
  <p>here is my layout</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.v7.widget.CardView
      xmlns:card_view="http://schemas.android.com/apk/res-auto"
      xmlns:android="http://schemas.android.com/apk/res/android"
      android:id="@+id/card_view"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      card_view:cardCornerRadius="4dp"
      card_view:cardPreventCornerOverlap="false"
      &gt;
  
      &lt;RelativeLayout
          android:layout_width="match_parent"
          android:layout_height="100dp"
          android:id="@+id/re1"&gt;
  
          &lt;TextView
              android:id="@+id/title"
              android:layout_width="match_parent"
              android:layout_height="20dp"
              android:background="@color/colorAccent"
              android:text="contact det"
              android:gravity="center_vertical"
              android:textColor="@android:color/white"
              android:textSize="14dp"/&gt;
  
          &lt;TextView
              android:id="@+id/txtName"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:text="Name"
              android:gravity="center_vertical"
              android:textSize="10dp"
              android:layout_below="@id/title"
              android:layout_marginTop="10dp"
              android:layout_marginLeft="5dp"/&gt;
  
          &lt;TextView
              android:id="@+id/txtSurname"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:text="Surname"
              android:gravity="center_vertical"
              android:textSize="10dp"
              android:layout_below="@id/txtName"
              android:layout_marginTop="10dp"
              android:layout_marginLeft="5dp"
              /&gt;
  
          &lt;TextView
              android:id="@+id/txtEmail"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:text="Email"
              android:textSize="10dp"
              android:layout_marginTop="10dp"
              android:layout_alignParentRight="true"
              android:layout_marginRight="150dp"
              android:layout_alignBaseline="@id/txtName"/&gt;
  
          &lt;TextView
              android:id="@+id/txtAdd"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:text="Address"
              android:textSize="10dp"
              android:layout_alignLeft="@id/txtEmail"
              android:layout_alignBaseline="@id/txtSurname"/&gt;
  
      &lt;/RelativeLayout&gt;
  
  
      &lt;/android.support.v7.widget.CardView&gt;
  </code></pre>