'android.annotation.NonNull' is not public in 'android.annotation'. Cannot be accessed from outside package

Question

I get this warning when I try to list data. Does anyone know why?

Answer 1

You're referring to the Android platform's internal annotations, which aren't the ones you want to use for your own code. For your code, you should import the AndroidX versions of those annotations:

androidx.annotation.NonNull

androidx.annotation.Nullable

etc. (note the extra x in androidx vs android)

You'll also want to make sure you have declared a dependency on androidx.annotation:annotation in your build.gradle (see here for the latest version information)