实战深研：构建高可靠、低延迟的 Flutter + OpenHarmony 智慧教育互动平台（支持离线教学、多端协同与国产化适配）

math_lesson_01.eduoff
├── manifest.json        # 元数据：标题、年级、版本、依赖
├── index.html           # 兼容 Web 渲染（备用）
├── assets/
│   ├── slides.pdf       # 主课件（PDF 或自定义格式）
│   ├── video.mp4        # 教学视频
│   └── interactive.js   # 互动逻辑（可选）
└── flutter_assets/      # Flutter 编译后的资源
    ├── fonts/
    ├── images/
    └── kernel_blob.bin

class OfflineLessonLoader {
  static Future<Lesson> loadFromPackage(String packagePath) async {
    final zip = ZipFile.open(packagePath);
    final manifest = jsonDecode(zip.read('manifest.json'));

    // 验证完整性（SHA256）
    if (!await _verifyIntegrity(zip, manifest['hash'])) {
      throw IntegrityException('课件包被篡改');
    }

    // 解压到安全目录
    await zip.extractTo('/data/lessons/${manifest['id']}');

    // 加载 Flutter 资源
    final engine = await FlutterEngineGroup.createAndRunDefaultEngine();
    engine.assetsBundlePath = '/data/lessons/${manifest['id']}/flutter_assets';

    return Lesson(
      id: manifest['id'],
      title: manifest['title'],
      engine: engine,
    );
  }
}

class ClassroomBus {
  final String teacherId = await Device.getDeviceId();

  Future<void> startClassroom() async {
    // 广播“课堂开启”
    await DSoftBus.publish({
      'service': 'edu_classroom',
      'teacherId': teacherId,
      'lessonId': currentLesson.id,
    });

    // 监听学生加入
    DSoftBus.onDeviceJoin((device) {
      _students.add(device);
      _sendSyncState(device); // 同步当前课件页
    });
  }

  Future<void> sendQuiz(Quiz quiz) async {
    final payload = jsonEncode({
      'type': 'quiz',
      'data': quiz.toJson(),
      'timestamp': DateTime.now().millisecondsSinceEpoch,
    });

    // 广播至所有学生
    for (final student in _students) {
      await DSoftBus.sendMessage(student.id, payload);
    }
  }
}

flutter:
  renderer: vulkan
  enable_impeller: true  # 启用新一代渲染引擎

// lib/platform/edu_platform.dart
abstract class EduPlatform {
  static bool get isLowEndDevice => _detectLowEnd();

  static Future<String> getSystemFont() async {
    if (FMLPlatform.isOhos) {
      return '/system/fonts/HarmonyOS_Sans_SC.ttf';
    } else if (FMLPlatform.isLoongArch) {
      return '/usr/share/fonts/loongson-sans.ttf';
    }
    return 'Roboto';
  }
}

# fml.config.yaml
build:
  targets:
    - ohos_arm64     # 麒麟/统信
    - loongarch64    # 龙芯
    - x86_64_kylin   # 飞腾+银河麒麟
  signing:
    profile: edu_trusted
    certificate: ./certs/edu_gov.p12
  optimization:
    strip_debug_symbols: true
    compress_assets: brotli