Flutter, provider and a Future async function (http post request)

Question

i am trying to call an (Future) http post request in a ChangeNotifier class. That means, after the Future is completed, the notifyListeners() should be called (see example below).

No matter, what I tried, in the ChangeNotifier - App_State_Controller class, the function callAPI executes its functions not in the correct order, waiting for the API request (despite the await keyword) and then executing the setText and therefore notifyListeners() (I also used the a combination using futureFunction.then((){})).

In a previous answer on stackoverflow it is suggested to either set the state of a stateful widget or use a FutureBuilder. In principle, the setText(text) notifyListeners() updates many widgets.

Do you have any idea how to solve this problem if possible within the ChangeNotifier class??

import 'package:flutter/material.dart';
import 'dart:async';
import 'dart:convert';
import 'package:http/http.dart' as http;
import 'package:provider/provider.dart';


Future<Map> getHttpPost(String httpURL,String text) async {
  // According to //https://docs.flutter.dev/cookbook/networking/fetch-data
  final http.Response response = await http.post(
      Uri.parse(httpURL),
      headers: <String, String>{
        'Content-Type': 'application/json; charset=UTF-8',
        'Access-Control-Allow-Origin': '*'
      },
      body: jsonEncode(<String, String>{
        "information_text"  : text,
      }
      ));
  if(response.body.isNotEmpty) {
    if (response.statusCode == 200) {
      return json.decode(response.body);
    } else {
      return {};
    }
  }else{
    return {};
  }
}

class App_State_Controller extends ChangeNotifier {
  Map AnalysisResults                   = {"text":"defaulttext"};
  String anotherStringVariable          = "";

  Future<void> callAPI (String token,String text) async {
    AnalysisResults = await getHttpPost(token, text);
    // The problem is here: Instead of waiting for the
    // AnalysisResults to arrive, it calls setText and
    // activates the notifyListener with an OLDER TEXT!
    setText(AnalysisResults["text"]);
  }

  void setText(String new_text) {
    anotherStringVariable = new_text;
    notifyListeners();
  }
}