Supabase and problem with fetch data - problem with read data

I have I think a simple problem but I cannot find the solution for that ...
I use library supabase_flutter

All elements are configured like anonKey and url.

I have this code:

import 'package:flutter/material.dart';

class HomeScreen extends StatefulWidget {
  const HomeScreen({super.key});

  @override
  State<HomeScreen> createState() => _HomeScreenState();
}

class _HomeScreenState extends State<HomeScreen> {
  List<String> categoryNames = [];

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

  Future<void> fetchCategories() async {
    // Perform the Supabase query
    final response = await supabase.from('main_categories').select('name');

    print(response);
  }

  @override
  Widget build(BuildContext context) {
    print(categoryNames.toString());
    return Scaffold(
      body: Center(
        child: Text(''),
      ),
    );
  }
}

So as you can see very simple code. My idea is to add elements from response to my list categoryNames.

I try to use Gemini & ChatGPT to help me but all this AI give me code that didn't works.

For example Gemini say:

Future<void> fetchCategories() async {
  try {
    // Perform the Supabase query
    final response = await supabase.from('main_categories').select('name');
    
    // Access data based on your Supabase version (refer to previous responses)
    final List<dynamic> decodedData = response.data; // Or appropriate method

    // Extract category names
    categoryNames.clear(); // Clear existing categories (optional)
    for (final item in decodedData as List<Map<String, dynamic>>) {
      categoryNames.add(item['name'] as String);
    }
    
    // Update UI (explained in step 2 of previous response)
    setState(() {});
  } catch (error) {
    // Handle database or connection errors here
    print("Error fetching categories: $error");
    // Show an error message in the UI (explained in step 2)
  }
}

my debugger say:

The getter 'data' isn't defined for the type 'List<Map<String, dynamic>>'.
Try importing the library that defines 'data', correcting the name to the name of an existing getter, or defining a getter or field named 'data'.dartundefined_getter
Type: InvalidType

I try to use .read, .data etc and I don't know how to do this ...

Please help or explain me where is the problem
Thank you for your help

You can do it like this :

Future<void> fetchCategories() async {
  // Perform the Supabase query
  final categoriesFetched = await supabase
      .from('main_categories')
      .select('name')
      .withConverter((list) {
    return list.map((data) => data['name'] as String).toList();
  });

  WidgetsBinding.instance.addPostFrameCallback((timeStamp) { // Perform setState safely
    setState(() {
      categoryNames = List.from(categoriesFetched);
    });
  });
}

Consider using FutureBuilder, in this case you can replace :

WidgetsBinding.instance.addPostFrameCallback((timeStamp) { // Perform setState safely
    setState(() {
      categoryNames = List.from(categoriesFetched);
    });
});

to :

setState(() {
    categoryNames = List.from(categoriesFetched);
});