【Flutter】抽象类的运用（abstract与implements的实践）

使用场景：功能支持两种接口模式，使用抽象类分别实现接口

1、定义抽象类及统一接口

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abstract class UploadStrategy {
  /// 抽象上传方法
  /// [file]：待上传文件
  /// [onSendProgress]：进度回调（已上传字节数，总字节数）
  Future<String> upload({
    required File file,
    Function(int, int)? onSendProgress
  });
}

2、通过创建策略工厂类（根据类型获取上传实例）

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class UploadStrategyFactory {
  static UploadStrategy getStrategy(
    UploadApiType type) {
    switch (type) {
      case UploadApiType.aLiYun:
        return AliYunUploader();
      case UploadApiType.sam:
        return SamUploader();
    }
  }
}

3、通过implements分别实现自定义上传接口

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/// 阿里云OSS上传实现
class AliYunUploader implements UploadStrategy {
  @override
  Future<String> upload({
    required File file,
    Function(int, int)? onSendProgress
  }) async {
    // 复用原阿里云上传逻辑
    return await AliyunOss.upload(
      file: file,
      onSendProgress: onSendProgress,
    );
  }
}

//上传实现
class SamUploader implements UploadStrategy {
  @override
  Future<String> upload({
    required File file,
    Function(int, int)? onSendProgress
  }) async {
    return await FileUploadService()
        .uploadCommon(file);
  }
}

4、使用示例：

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 final uploader = UploadStrategyFactory.getStrategy(uploadType);
    try {
      final urls = await Future.wait(
        files.map(
          (file) => uploader.upload(
            file: file,
            onSendProgress: onSendProgress,
          ),
        ),
      );

      UIToast.showSuccess('上传成功');
      successCallback(urls);
    } catch (e) {
      UIToast.showError('上传失败: ${e.toString()}');
    } finally {
      UIToast.dismissHud();
    }

总结：虽然可以通过参数方式实现不同类型接口的功能，但通过抽象类可以减少逻辑，并更加简便的使用上传方法，后期若有增加类型，也更容易维护。