A Simple solution :
Create a drawable file as edittext_stroke.xml in drawable folder. Add the below code:
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="line"
>
<stroke
android:width="1dp"
android:color="@android:color/white" >
</stroke>
</shape>
In layout file , add the drawable to edittext as
android:drawableBottom="@drawable/edittext_stroke"
<EditText
android:textColor="@android:color/white"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:drawableBottom="@drawable/edittext_stroke"
/>