我的结构不符合协议“可解码” /“可编码” [英] My structure does not conform to protocol 'Decodable' / 'Encodable'

问题描述

我试图使用Codable从正在创建的应用程序中保存数据，但是当我将Codable放入我的结构时，我不断收到错误消息：

I was trying to use Codable to save my data from the app I am creating but when I put Codable into my structure I keep getting the error:

类型'ReminderGroups'不符合协议'可解码'

Type 'ReminderGroups' does not conform to protocol 'Decodable'

and

类型'ReminderGroups'不符合协议'Encodable'

Type 'ReminderGroups' does not conform to protocol 'Encodable'

struct ReminderGroups: Codable {
    var contentsArray: [ReminderItem] = []
    var reminderName: String = ""
    var reminderItem: UIImage = #imageLiteral(resourceName: "Folder")
}

推荐答案

为了使某个类或结构符合协议，该类或结构的所有属性必须符合同一协议。

In order for a class or a struct to conform to a protocol, all properties of that class or struct must conform to the same protocol.

UIImage 不符合 Codable ，因此任何属性类型为 UIImage 的类或结构都不会也符合。您可以将图像替换为图像数据或图像的base64表示形式（如 String ）。

UIImage does not conform to Codable, so any class or struct that has properties of type UIImage won’t conform as well. You can replace the image with image data or the image’s base64 representation (as String).

我将显示您是第一个选择。我想您不想每次写如果让，那么让我们添加两个小的扩展名到 UIImage 和 Data 可以加快未来的转换速度。

I’ll show you the first option. I suppose you don’t want to write those if lets every time, so let’s add two little extensions to UIImage and Data that will speed up future conversions.

extension UIImage {
    var data: Data? {
        if let data = self.jpegData(compressionQuality: 1.0) {
            return data
        } else {
            return nil
        }
    }
}

extension Data {
    var image: UIImage? {
        if let image = UIImage(data: self) {
            return image
        } else {
            return nil
        }
    }
}

将 reminderItem 的类型从 UIImage 到 Data 。

从现在开始，在需要时要访问图像，请编写类似 imageView.image = hinterGroup.reminderItem.image 的内容。然后，当您需要将 UIImage 的实例保存到 reminderItem 时，编写类似 reminderGroup的内容。 hinterItem = image.data！（需要bang运算符（感叹号），因为计算出的属性 data 是可选的）。

From now on, when you need to access the image, write something like imageView.image = reminderGroup.reminderItem.image. And when you need to save an instance of UIImage to reminderItem, write something like reminderGroup.reminderItem = image.data! (the bang operator (exclamation mark) is needed because the computed property data is optional).

还要确保 ReminderItem 确实符合 Codable 。您没有提供该类型的声明，所以我不能说它是否符合。

Also make sure ReminderItem does conform to Codable. You didn’t provide the declaration of that type, so I can’t say whether it conforms of not.

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