How to change fontFamily of TextView in Android

So I'd prefer to change the android:fontFamily in Android however I don't perceive any pre-characterized text styles in Android. How would I choose one of the pre-characterized ones? I don't actually have to characterize my own TypeFace however all I need is something other than what's expected from what it shows at this moment.

<TextView

    android:id="@+id/HeaderText"

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:layout_alignParentTop="true"

    android:layout_centerHorizontal="true"

    android:layout_marginTop="52dp"

    android:gravity="center"

    android:text="CallerBlocker"

    android:textSize="40dp"

    android:fontFamily="Arial"

 />