Codable class 不符合“可解碼”協議

Question

嘗試在結構中添加枚舉 Codingkeys，但它顯示錯誤 Codable doesn't conform Decodable。

為什么我會收到一致的可解碼錯誤？ 我應該分開結構嗎？

struct Model: Codable {
    let aps: Aps
    let link: String?
    let checkAction: String?
   
    enum CodingKeys: String, CodingKey {
           case aps ,link, alert,sound,title,body
           case checkAction = "gcm.notificaiton.check_action"
    }
    
    struct Aps: Codable {
        let alert: Alert
        let sound: String?
       
        
        struct Alert: Codable {
            let title: String?
            let body: String?
        }
    }
   

}

是否必須像下面這樣分離結構？

struct FCMModel: Codable {
    let aps: Aps
    let link: String?
    let checkAction: String?
   
    enum CodingKeys: String, CodingKey {
           case aps ,link
           case checkAction = "gcm.notificaiton.check_action"
    }
    

}
struct Aps: Codable {
    let alert: Alert
    let sound: String?
   
    
    struct Alert: Codable {
        let title: String?
        let body: String?
    }
}

Answer 1

沒有必要分離結構。 發生錯誤是因為您在CodingKeys枚舉中添加了太多鍵。 如果您只保留所需的，那么它將起作用：

struct Model: Codable {
    let aps: Aps
    let link: String?
    let checkAction: String?
   
    enum CodingKeys: String, CodingKey {
           case aps ,link
           case checkAction = "gcm.notificaiton.check_action"
    }
    
    struct Aps: Codable {
        let alert: Alert
        let sound: String?
       
        
        struct Alert: Codable {
            let title: String?
            let body: String?
        }
    }
}

alert 、 sound等不是Model的編碼鍵。 它們是Aps的編碼鍵。 不必在Aps中指定它們，因為它們與屬性名稱相同。