在flutter中获取JSON数据返回NULL

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

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

class _MyWidgetState extends State<MyWidget> {
  List<dynamic> jsonData = [];

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

  Future<void> fetchData() async {
    final response = await http.get(Uri.parse('https://example.com/api/data.json'));
    if (response.statusCode == 200) {
      setState(() {
        jsonData = json.decode(response.body);
      });
    } else {
      print('Failed to fetch data');
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('JSON Data'),
      ),
      body: ListView.builder(
        itemCount: jsonData.length,
        itemBuilder: (context, index) {
          return ListTile(
            title: Text(jsonData[index]['title']),
            subtitle: Text(jsonData[index]['description']),
          );
        },
      ),
    );
  }
}