Question

enum Media {
  case image
  case video
}

struct UploadManager {

  static func upload(mediaType: Media, data: AnyObject, completion: Response -> Void) {
    switch mediaType {
    case .image:
        uploadImage(data as? UIImage, completion: completion)
    case .video:
        uploadVideo(data as? NSURL, completion: completion)
    }
  }

  static func uploadImage(image: UIImage, completion: Response -> Void ) {
    let imageData = UIImagePNGRepresentation(image)! as NSData
    let options = ["resourcetype": "image"]
    //API call
  }

  static func uploadVideo(filePath: NSURL, completion: Response -> Void ) {
    let options = ["resourcetype": "video"]
    //API call

  }
}

示例通话将是：

UploadManager.upload(.image, data: data, completion: {

})

这里我使用.image类型和数据向UploadManager发出请求。我担心的是图像和数据是互斥的，容易出错。说，我通过了.image而不是.video，而向下转发会导致崩溃。任何方式来处理这个问题

Answer 1

您可以在枚举中嵌入数据。例如：

enum Media {
  case Image(image: UIImage)
  case Video(url: NSURL)
}

您可以在match-case：

中提取它们

static func upload(media: Media, completion: Response -> Void) {
    switch media {
    case .Image(let image):
        uploadImage(image, completion: completion)
    case .Video(let url):
        uploadVideo(url, completion: completion)
    }
}

然后，你可以这样调用这个方法：

let image = UIImage()
UploadManager.upload(.Image(image)) { response in
    print("Upload complete!")
}

如何避免丢失类型？

1 个答案: