[Android] Elevation on Pre-lollipop Devices

shadow.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" 
       android:shape="rectangle">
  
  <gradient
    android:startColor="@android:color/transparent"
    android:endColor="#44000000"
    android:angle="90"/>
  
</shape>