How to change the font size of an textview element in Android?

I am trying to display 2 items in a TextView. Is their any way to change the font of the single item in a TextView?

Here is the XML which I am using

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TextView
        android:gravity="center_horizontal"
        android:paddingTop="5dp"
        android:paddingBottom="5dp"
        android:id="@+id/Rowtext"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:text="Listiems"
        android:background="@drawable/customshape"
         />

</LinearLayout>