how to display data from json api using flutter expansiontile

To display data from a JSON API using Flutter's ExpansionTile widget, you can follow these steps:

Make sure you have the necessary dependencies added to your pubspec.yaml file. You will need the http package to make API requests and the flutter_spinkit package for loading indicators. Here is an example of how to add these dependencies:

dependencies:
  flutter:
    sdk: flutter
  http: ^0.13.4
  flutter_spinkit: ^5.1.0

Import the necessary packages in your Dart file:

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

Create a class to represent the data you will receive from the API. This class should have properties that match the JSON structure. For example:

class MyData {
  final String title;
  final List<String> items;

  MyData({required this.title, required this.items});

  factory MyData.fromJson(Map<String, dynamic> json) {
    return MyData(
      title: json['title'],
      items: List<String>.from(json['items']),
    );
  }
}

Create a stateful widget that will fetch the data from the API and display it using the ExpansionTile widget. Here is an example:

class MyWidget extends StatefulWidget {
  @override
  _MyWidgetState createState() => _MyWidgetState();
}

class _MyWidgetState extends State<MyWidget> {
  late Future<List<MyData>> _data;

  @override
  void initState() {
    super.initState();
    _data = fetchData();
  }

  Future<List<MyData>> fetchData() async {
    final response = await http.get(Uri.parse('https://example.com/api/data'));
    if (response.statusCode == 200) {
      final List<dynamic> jsonData = jsonDecode(response.body);
      return jsonData.map((item) => MyData.fromJson(item)).toList();
    } else {
      throw Exception('Failed to load data');
    }
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder<List<MyData>>(
      future: _data,
      builder: (context, snapshot) {
        if (snapshot.hasData) {
          return ListView.builder(
            itemCount: snapshot.data!.length,
            itemBuilder: (context, index) {
              final data = snapshot.data![index];
              return ExpansionTile(
                title: Text(data.title),
                children: data.items.map((item) => ListTile(title: Text(item))).toList(),
              );
            },
          );
        } else if (snapshot.hasError) {
          return Text('Error: ${snapshot.error}');
        } else {
          return Center(child: CircularProgressIndicator());
        }
      },
    );
  }
}

Replace 'https://example.com/api/data' with the actual URL of your JSON API endpoint.
Use the MyWidget in your app's build method or wherever you want to display the data:

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('My App')),
        body: MyWidget(),
      ),
    );
  }
}

That's it! The ExpansionTile widgets will display the data from the JSON API in an expandable format.