Error in Ch 31: Expected a value of type 'DatabaseNote', but got one of type 'Null'

[athyg]

Hi there,

I'm an old-shool developer & haven't been hand-on coding for over 20 yrs and hoping to upskill by completing this tutorial.
Just working my way through your tutorial; all going great till I got to Chapter 31: Creating New Notes and I'm getting an error:
"Expected a value of type 'DatabaseNote', but got one of type 'Null'"
Don't know where to start troubleshooting, so hoping for some expert assistance.
FYI - I'm not using the Android emulator; just testing using the web app version - is that the problem here?
Based on comments in an earlier issue, it seems that code implemented in this chapter is tailored to smart phone devices, rather than a web app. Is there a version of code that works on the web?