Question

我希望我的strcut符合可解码的要求，但是尽管我遵守，但我总是会收到此错误。

类型“ DBTweet”不符合协议“可解码”

那是我的代码：

struct DBTweet {
    private(set) public var user: DBUser
    private(set) public var profileImage: UIImage?
    private(set) public var tweetID: Int
    private(set) public var content: String
    private(set) public var postedImageURL: String?
    private(set) public var timestamp: String
    private(set) public var comments: [DBComment]
}

extension DBTweet: Decodable {
    enum MyStructKeys: String, CodingKey { // declaring our keys
        case user, tweetID, content, postedImageURL, timestamp, comments
    }

    init(from decoder: Decoder) throws {

    }
}

Answer 1

您尚未实现init（来自：Decoder）。如果所有模型属性都符合Codable，则也可以使模型符合Codable（Decodable），而无需实现它们。

struct DBTweet: Codable {
    private(set) public var user: DBUser
    private(set) public var profileImage: UIImage?
    private(set) public var tweetID: Int
    private(set) public var content: String
    private(set) public var postedImageURL: String?
    private(set) public var timestamp: String
    private(set) public var comments: [DBComment]
}

确保DBUser和DBComment也符合Codable

[更新] 使用init：

struct DBTweet: Decodable {
    private(set) public var user: DBUser
    private(set) public var profileImage: UIImage?
    private(set) public var tweetID: Int
    private(set) public var content: String
    private(set) public var postedImageURL: String?
    private(set) public var timestamp: String
    private(set) public var comments: [DBComment]

    enum CodingKeys: String, CodingKey {
        case user, tweetID, content, postedImageURL, timestamp, comments
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        self.user = try container.decode(DBUser.self, forKey: .user)
        self.profileImage = nil // Construct here your profileImage
        self.tweetID = try container.decode(Int.self, forKey: .tweetID)
        self.content = try container.decode(String.self, forKey: .content)
        self.postedImageURL = try container.decodeIfPresent(String.self, forKey: .postedImageURL)
        self.timestamp = try container.decode(String.self, forKey: .timestamp)
        self.comments = try container.decode([DBComment].self, forKey: .comments)
    }
}

类型“ DBTweet”不符合协议“可解码”

1 个答案: