Here is simple snippet for making imitation of underline for textview. To use it – just set it as a textview’s background.
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
tools:background="#EDF5F5">
<item
android:bottom="10dp"
android:gravity="bottom"
android:left="4dp"
android:right="4dp">
<shape>
<corners android:radius="1dp" />
<size android:height="2dp" />
<solid android:color="#FF0000" />
</shape>
</item>
</layer-list>
Preview:

