Use a RelativeLayout with layout_alignParentLeft and layout_alignParentRight:
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/RelativeLayout01"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="10dp">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:id="@+id/mytextview1"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:id="@+id/mytextview2"/>
</RelativeLayout>
Also, you should probably be using dip (or dp) rather than sp in your layout. sp reflect text settings as well as screen density so they’re usually only for sizing text items.