Unhandled Exception: inheritFromWidgetOfExactType(_LocalizationsScope) or inheritFromElement() was called before _ScreenState.initState() completed

Question

I am calling initial method to load data from API using initState. But it is resulting me an error. Here is error:

Unhandled Exception: inheritFromWidgetOfExactT         


        

Answer 1

You need to call _getCategories after initState has completed.

@override
void initState() {
   super.initState();

   Future.delayed(Duration.zero, () {
      this._getCategories();
   });

   // Could do this in one line: Future.delayed(Duration.zero, this._getCategories);
}

Also, you could do this on a different way, using addPostFrameCallback like showed in another answers.

Answer 2

Use the didChangeDependencies method which gets called after initState.

For your example:

@override
void initState() {
  super.initState();
}

@override
void didChangeDependencies() {
  super.didChangeDependencies();

  this._getCategories();
}

void _getCategories() async {
  // Omitted for brevity
  // ...

 }

Answer 3

The best solution i think is use the context from the Widget build. And paste the method _getCategories(context) after the build with the context from the tree. So there is no problem with the widget tree.

Answer 4

Adding a frame callback might be better than using Future.delayed with a zero duration - it's more explicit and clear as to what is happening, and this kind of situation is what frame callback was designed for:

@override
  void initState() {
    super.initState();

    WidgetsBinding.instance.addPostFrameCallback((_) async {
      _getCategories();
    });
  }

Answer 5

There are many ways to solve this problem, override initState method:

@override
void initState() {
  super.initState();
  // Use any of the below code here. 
}

• Using SchedulerBinding mixin:

  SchedulerBinding.instance.addPostFrameCallback((_) {
    // Call your function
  });
  

• Using Future class:

  Future(() {
    // Call your function
  });
  

• Using Timer class:

  Timer(() {
    // Call your function
  });
  

Answer 6

an alternative is to put it inside PostFrameCallback which is between initState and Build so we can be sure that the initState is already finished.

 @override
  void initState() {
    WidgetsBinding.instance.addPostFrameCallback((_) => getData());
    super.initState();
  }

  getData() async {

  }