Create drawable vertical dotted line, its the bottom edge of the rectangle.

vertical_dotted_line.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:top="-2.5dp"
        android:bottom="-2dp"
        android:right="-2dp">
        <shape>
            <solid android:color="@android:color/transparent"/>
            <stroke
                android:width="2dp"
                android:color="@color/blue"
                android:dashGap="4dp"
                android:dashWidth="2dp"/>
        </shape>
    </item>
</layer-list>