Non-nullable instance field 'Welcome' must be initialized Flutter-CodePudding

I am trying to call API's in flutter but when I am defining the variable _Welcome I am getting this error. Does anyone know how to fix it?

class _PostsPageState extends State<PostsPage> {
Future<Welcome> _Welcome; //error here


@override
void initState() {
_Welcome = API_Manager().getNews();
super.initState();
}

CodePudding user response：

This error due to the null-safety property of flutter. So, what is null-safety? Flutter null safety is the feature that became available after the release of version 2. This feature helps to improve developers' productivity by eliminating a whole class of bugs caused by null dereferencing errors. So, how can you solve this problem? Actually, there are many options for that; you can initialize the variable at the time of the declaration, or you can use late keyword such as late Future<Welcome> _Welcome;

CodePudding user response：

try late Future<Welcome> _Welcome;

With this you promise to the compiler that it is initialized when it's accessed later on. Since you assing it directly in the initState that is fine.

CodePudding user response：

Your Future is not used with the late keyword, so the Dart analyzer expects it to be instantly initialized.

Either do:

late Future<Welcome>. _Welcome;

@override
void initState() {
_Welcome = API_Manager().getNews();
super.initState();
}

or just at the start:

Future<Welcome> _Welcome = API_Manager().getNews();

CodePudding user response：

Use late Future<Welcome> _welcome;