PagerTabStrip is an interactive indicator of the current, next,
and previous pages of a ViewPager.
PagerTitleStrip is a non-interactive indicator of the current, next,
and previous pages of a ViewPager. It is intended to be used as a
child view of a ViewPager widget in your XML layout.
Add it as a child of a ViewPager in your layout file and set its
android:layout_gravity to TOP or BOTTOM to pin it to the top or bottom
of the ViewPager. The title from each page is supplied by the method
getPageTitle(int) in the adapter supplied to