I was also looking for a solution to this problem and as easy and comfortable I found, was to convert the shape of a rectangular TextView to cirular. With this method will be perfect:
-
Create a new XML file in the drawable folder called “circle.xml” (for example) and fill it with the following code:
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval"> <solid android:color="#9FE554" /> <size android:height="60dp" android:width="60dp" /> </shape>
With this file you will create the new form of TextView. In this case, I created a circle of green. If you want to add a border, you would have to add the following code to the previous file:
<stroke
android:width="2dp"
android:color="#FFFFFF" />
-
Create another XML file ( “rounded_textview.xml”) in the drawable folder with the following code:
<?xml version="1.0" encoding="utf-8"?> <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:drawable="@drawable/circle" /> </selector>
This file will serve to change the way the TextView we eligamos.
-
Finally, in the TextView properties we want to change the way section, we headed to the “background” and select the second XML file created ( “rounded_textview.xml”).
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="H" android:textSize="30sp" android:background="@drawable/rounded_textview" android:textColor="@android:color/white" android:gravity="center" android:id="@+id/mark" />
With these steps, instead of having a TextView TextView rectagular have a circular. Just change the shape, not the functionality of the TextView. The result would be the following:

Also I have to say that these steps can be applied to any other component having the option to “background” in the properties.
Luck!!