Ahh, I get it now.
Regarding the reuse of the id crime_id in fragment_crime.xml and list_item_crime.xml, note that the Android documentation states that ids need not be unique across the entire application. In our case, the build process generates a single crime_id integer in R.java. But then the question is, doesn’t that id map to a single view widget? (It doesn’t.) And if so, how can it be mapping to two different widgets? This is because the existence of these ids in R.java is separate from how they are used. Each parent View object maintains its own tree of widgets. When building this tree, it uses the id values in R.java. But these view trees are independent - hence, we can use the same id in separate XML views. Despite this, it is not recommended to do this.