<?xml version="1.0" encoding="utf-8"?>
<!--Change angle depending where you want it:-->
<!-- 0   = left-->
<!-- 90  = bottom-->
<!-- 180 = right-->
<!-- 270 = top-->
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <gradient
        android:angle="270"
        android:startColor="@android:color/transparent"
        android:endColor="@color/grey_70"
        android:centerX="0.01"/>
</shape>