without an additional -ktx library to add an exten...

# android

[Adam Powell]

without an additional -ktx library to add an extension overload of observe that accepts an observer lambda, you have to supply both the LifecycleOwner and the Observer as lambdas or neither of them, since LifecycleOwner is a SAM interface and kotlin's SAM conversion is all or nothing for a method. As for Observer value nullability, yes, but the LiveData library still targets jdk7 and type annotations weren't a thing until jdk8, plus the nullability of LiveData values is a bit weird since it doesn't require a default value on construction; getValue can return null if a value hasn't been set yet.