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I'm new to flutter and trying to use spread operator and Map into a List but I get null safety error , tried using (!) but no good.

CodePudding user response：

Although I don't quite understand what you are talking about, I roughly understand where your code is wrong.

This is the example code:

change

_snapshot.data!.name

to

_snapshot.data?.name ?? "Unknown"

CodePudding user response：

First, maybe to someone reading this you have already edited your question as asked in the comments by @nagendra nag and @CLucera. Your error should stop if you just change this:

(questions[indexNum]['answers'] as List<String>)

to this:

((questions[indexNum]['answers'] ?? []) as List<String>)

The error is about the 'answers' field being empty or null and you are trying to cast it as a non-nullable List. I suggested the above instead of just casting it to List<String>? because if you cast it this way, the map operation would have to be called on a nullable value (yourListCasted?.map(...)) and that would mean that this could not be called, making the spread operator complain about the object not being a List.