Page 3 of codelab says it will use ObservableFields and then uses LiveData

[dmcg]

There are multiple ways to implement observability. You can use observable classes, observable fields, or, the preferred way, LiveData. The full documentation on that is here.

We're going to use ObservableFields as they are simpler. ...

Replace ... with the new LiveDatas:

[le-kamba]

It's now on page 7.

[davidfrancisandroidemul]

It's a year later. The problem is still there. Edit: This sounds snarky when it was supposed to be amusing - apologies - anyhow, the issue is still there, the text is a bit confusing. Still a great tutorial though.