I’m not sure whether I just overlooked it somewhere prior to page 190, but when I got to page 190 and added the code at the bottom of the page to create AppBarConfiguration(bottomNav.menu), I got an error because bottomNav was never defined.

After comparing my MainActivity.kt to the one from chapter 7 of the zipfile, I noticed that the zipfile changed

findViewById<BottomNavigationView>(R.id.bottom_nav).setupWithNavController(this.navController)

to

val bottomNav = findViewById<BottomNavigationView>(R.id.bottom_nav) bottomNav.setupWithNavController(this.navController)

It’s entirely possible you mentioned it earlier in the book & I just overlooked it. (Sigh… I wish publishers would bundle codes for free copies of the ebook with printed copies, or work out something with Amazon like, “buy the printed book, immediately get the Kindle version free”. Ebooks suck for actual reading, but they occasionally come in handy as super-indexes that can be brute-force searched for situations like this.)

I also noticed a minor issue with the way the penny_drop_created_by entry in strings.xml is encoded… the double quotes around the book’s title need to be backslash-escaped, or they won’t be printed:

<string name="penny_drop_created_by">The <i>Penny Drop</i> app was created by Michael Fazio for the Pragmatic Bookshelf title <a href="https://pragprog.com/titles/mfjetpack/">\"Kotlin and Android Development featuring Jetpack\"</a>.</string>

As an aside, for your own future projects, you might want to check out https://noties.io/Markwon as a convenient alternative to SpannableString. I discovered it a few months ago & totally fell in love with it