👀 Views: 6719 💬 Answers: 1 📅 Created: 2025-06-14

flutter dart json Dart

I'm stuck trying to I'm collaborating on a project where I'm experiencing an scenario in my Flutter web application where I need to cast a list of dynamic objects to a specific type... The dynamic list is coming from a JSON response that I'm decoding. When I try to cast it to a list of a specific model, I get an 'Invalid Cast' exception. Here's the relevant code snippet: ```dart import 'dart:convert'; import 'package:flutter/material.dart'; class MyModel { final String name; MyModel({required this.name}); factory MyModel.fromJson(Map<String, dynamic> json) { return MyModel( name: json['name'], ); } } Future<List<MyModel>> fetchData() async { final response = await http.get(Uri.parse('https://api.example.com/data')); if (response.statusCode == 200) { List<dynamic> jsonResponse = json.decode(response.body); return jsonResponse.map((item) => MyModel.fromJson(item)).toList(); } else { throw Exception('Failed to load data'); } } class MyHomePage extends StatelessWidget { @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar(title: Text('My App')), body: FutureBuilder<List<MyModel>>( future: fetchData(), builder: (context, snapshot) { if (snapshot.connectionState == ConnectionState.waiting) { return CircularProgressIndicator(); } else if (snapshot.hasError) { return Text('behavior: ${snapshot.behavior}'); } else { return ListView.builder( itemCount: snapshot.data!.length, itemBuilder: (context, index) { return ListTile( title: Text(snapshot.data![index].name), ); }, ); } }, ), ); } } ``` When I run this code, I get the following behavior message: `type 'List<dynamic>' is not a subtype of type 'List<Map<String, dynamic>>'`. I suspect the scenario arises from the way the JSON is being parsed, but I've checked that the API response indeed returns a list of objects formatted correctly. I've also tried explicitly casting the list before mapping it: ```dart List<Map<String, dynamic>> jsonResponse = List<Map<String, dynamic>>.from(json.decode(response.body)); ``` However, this didn't resolve the scenario. Any suggestions on how to properly handle this dynamic list and avoid the casting behavior? Any suggestions would be helpful. Any pointers in the right direction?