I am going thru an online course, Android Studio 3.3 and using JetPack, AndroidX and Bottom Navigation (for a List/Tasks project). I strongly recommend the new updated RW book embrace these technologies and approach, especially for the ListMaker sections.
Bottom Navigation shows the power of Fragments (each ‘tab’ is a fragment, so List fragment, Task fragment, etc) and how Fragments call methods in Activities (e.g. to Intent to other activities, using Interfaces).
JetPack and AndroidX get rid of findByViewID and redundant var references to Layout elements and provide significant code optimisation. Check them out on Android Developers website.
All the best.