Android : Layout with Rounded drop shadow
you should add "corners" to the shape:
<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<solid android:color="#ffffffff"/>
<stroke android:width="3dp"
android:color="#ff000000"
/>
<padding android:left="1dp"
android:top="1dp"
android:right="1dp"
android:bottom="1dp"
/>
<corners android:radius="7dp"/>