Reloading the List
There is one more detail to take care of. Run CriminalIntent, press a list item, and then modify that Crime’s details. These changes are saved to the model, but when you return to the list, the RecyclerView is unchanged.
The RecyclerView’s Adapter needs to be informed that the data has changed (or may have changed) so that it can refetch the data and reload the list. You can work with the ActivityManager’s back stack to reload the list at the right moment.
When CrimeListFragment starts an instance of CrimeActivity, the CrimeActivity is put on top of the stack. This pauses and stops the instance of CrimeListActivity that was initially on top.
When the user presses the Back button to return to the list, the CrimeActivity ...