RealmSwift：需要公共 init() 错误

Question

import RealmSwift
import Realm

public class Card : Object {
    dynamic var username: String = ""
    dynamic var firstName: String = ""
    dynamic var lastName: String = ""

    convenience init?(dictionary: [String:Any]?) {
        guard let dictionary = dictionary , let username =  dictionary["username"] as? String else { return else}
        self.init()
        self.username = username
        self.firstName = firstName 
        self.lastName = lastName
    }

    required public init() {
        fatalError("init() has not been implemented")
    }

    required public init( realm: RLMRealm, schema: RLMObjectSchema) {
        fatalError("init(realm:schema:) has not been implemented")
    }

    required public init( value: Any, schema: RLMSchema) {
       fatalError("init(value:schema:) has not been implemented")
    }
}

根据建议，我将变量设为动态 var 而不是 var，并将它们初始化为空字符串。最初，我使用 init() 和 init() 一样方便。添加领域后，便利 init() 根据建议调用 self.init() 。现在默认实现要求 throws

(fatalError("init() has not been implemented")

在所需的 public init() 中应该包含什么？是否需要重新初始化变量？

Answer 1

正如我在my answer to your previous question 中提到的，通过将您的init? 方法切换为便利初始化程序，不再需要覆盖超类中各种所需的初始化程序。您可以简单地从您的子类中删除三个 required public init 方法。

public class Card : Object {
    dynamic var username: String = ""
    dynamic var firstName: String = ""
    dynamic var lastName: String = ""

    convenience init?(dictionary: [String:Any]?) {
        guard let dictionary = dictionary,
            let username = dictionary["username"] as? String,
            let firstName = dictionary["firstName"] as? String,
            let lastName = dictionary["lastName"] as? String
            else { return nil }

        self.init()

        self.username = username
        self.firstName = firstName
        self.lastName = lastName
    }
}