Flutter配置googleCalendarAPI.json后仍提示文件找不到的问题

问题根源 #

你用File('assets/googleCalendarAPI.json')直接读取assets文件的方式是错误的。Flutter的assets资源是打包到应用程序包内的，并非存储在设备的文件系统路径中，因此无法通过File类直接访问。

解决方案 #

需要使用Flutter的rootBundle（来自flutter/services.dart）来加载assets文件，具体修改如下：

1. 导入必要的包 #

在代码文件顶部添加：

import 'package:flutter/services.dart' show rootBundle;

2. 修改initializeCalendarApi方法 #

替换原有的文件读取逻辑：

Future<void> initializeCalendarApi() async {
  // 使用rootBundle加载assets中的JSON文件
  final jsonString = await rootBundle.loadString('assets/googleCalendarAPI.json');
  final jsonMap = json.decode(jsonString) as Map<String, dynamic>;

  final credentials = auth.ServiceAccountCredentials.fromJson(jsonMap);
  final client = await auth.clientViaServiceAccount(credentials, _scopes);
  _calendarApi = calendar.CalendarApi(client);
}

额外检查项 #

• 确认pubspec.yaml中assets配置的缩进正确（YAML对缩进敏感，必须用空格而非Tab）：

  flutter:
    assets:
      - assets/googleCalendarAPI.json
  

• 执行flutter pub get命令，确保assets资源被正确注册
• 确认googleCalendarAPI.json文件确实位于项目根目录下的assets文件夹中（路径大小写要匹配，Flutter对路径大小写敏感）

完整修改后的代码示例 #

import 'package:flutter/services.dart' show rootBundle;
// 保留你原有的其他导入（比如googleapis、googleapis_auth等）

Future<void> initializeCalendarApi() async {
  final jsonString = await rootBundle.loadString('assets/googleCalendarAPI.json');
  final jsonMap = json.decode(jsonString) as Map<String, dynamic>;

  final credentials = auth.ServiceAccountCredentials.fromJson(jsonMap);
  final client = await auth.clientViaServiceAccount(credentials, _scopes);
  _calendarApi = calendar.CalendarApi(client);
}

Future<List<calendar.Event>> fetchWeekEvents(DateTime startDate) async {
  await initializeCalendarApi();

  final calendarId = '(imagine a calendar id here)';
  final startTime = startDate.subtract(Duration(days: startDate.weekday - 1));
  final endTime = startTime.add(Duration(days: 7));

  try {
    var events = await _calendarApi.events.list(
      calendarId,
      timeMin: startTime.toUtc(),
      timeMax: endTime.toUtc(),
      singleEvents: true,
      orderBy: 'startTime',
    );

    return events.items ?? [];
  } catch (e) {
    print('Error fetching events: $e');
    return [];
  }
}

内容的提问来源于stack exchange，提问作者DizzyDagem