在flutter中没有从json获取用户名的所有记录

{
  "users": [
    {
      "id": 1,
      "username": "user1"
    },
    {
      "id": 2,
      "username": "user2"
    },
    {
      "id": 3,
      "username": "user3"
    }
  ]
}

dependencies:
  flutter:
    sdk: flutter
  # 添加下面这行
  convert: ^2.15.0

import 'dart:convert';

// 读取JSON数据源
String jsonData = '''
{
  "users": [
    {
      "id": 1,
      "username": "user1"
    },
    {
      "id": 2,
      "username": "user2"
    },
    {
      "id": 3,
      "username": "user3"
    }
  ]
}
''';

// 解析JSON数据
var data = json.decode(jsonData);

// 获取用户名的所有记录
List<dynamic> users = data['users'];
List<String> usernames = users.map((user) => user['username']).toList();