On page 251, you talk about activity_crime_pager XML layout. Note that if you follow the book steps you don’t have this layout, you are never told to create it. In fact, if you do a search across all book you will see that this is the only place in the book where activity_crime_pager appears.
Please note that if you look at the code available for download for chapters 11 and 12 you do have this layout there! I believe you should remove it to avoid confusion.
Moreover, this layout is useless since we are setting the layout in code in CrimePagerActivity. The id for the ViewPager is set in res/values/ids.xml. Hence, there is no need to create this layout (activity_crime_pager).
Maybe this errata should appear in chapter 11, where ViewPager is introduced, but activity_crime_pager is only cited in page 251.