Applying shadow to custom grid view

I want to apply shadow to each cell of my custom grid view.

I want the output to be something like this:-

See the shadow below each cell, I want the shadow on each cell of my grid view like that.

My code:-

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://ift.tt/nIICcg" >
    <item >

        <shape 
            android:shape="rectangle">

            <corners
                android:radius="5dp"/>
            <gradient 
             android:startColor="#202020"
             android:endColor="#454545"
             android:angle="270"/>

        </shape>
        </item>

    <item 
        android:bottom="5dp">
        <shape
            android:shape="rectangle">

        <solid
            android:color="#202020"/>
         <corners
             android:radius="3dp"/>
         <stroke
        android:width="1dp"
        android:color="#ffffff" >
         </stroke>
         </shape>
    </item>


</layer-list>

Can anyone point out the improvement to this code. Thanks.