res/drawable/focused_button_shape.xml

<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <stroke
        android:width="2dp"
        android:color="#333333"/>
    <corners
        android:radius="7dp"/>
    <padding
        android:left="5dp"
        android:top="5dp"
        android:right="5dp"
        android:bottom="5dp"/>
</shape>