Creating it once and using it wherever needed is a good idea. Add this in your styles.xml:
<style name="Divider">
<item name="android:layout_width">match_parent</item>
<item name="android:layout_height">1dp</item>
<item name="android:background">?android:attr/listDivider</item>
</style>
and add this in your xml code, where a line divider is needed:
<View style="@style/Divider"/>
Originally answered by toddles_fp to this question: Android Drawing Separator/Divider Line in Layout?