使用Codable（Swift）从Json文件解析UIColor [英] Parse UIColor from Json file with Codable (Swift)

问题描述

我正在尝试解码json文件，并且我在那里有很多ui配置，我正在寻找一种干净的解决方案以直接将十六进制代码解析为UIColor。但是UIColor不符合Codable。

Im trying to decode a json file, and i have alot of ui configurations there, and im looking for a clean solution to parse directly a hex code to UIColor. But UIColor doesnt conform to Codable.

例如，此json：

var json = """
{
    "color": "#ffb80c"
}
""".data(using: .utf8)!

而我希望能够做到这一点：

and i want to be able to do this:

struct Settings: Decodable {
    var color: UIColor
}

，而即时解码将十六进制字符串转换为UIColor

and while im decoding convert the "hex" string into a UIColor

我已经具有此功能，可以从字符串中解码并返回UIColor：

I already have this function to decode from a String and return a UIColor:

public extension KeyedDecodingContainer {

    public func decode(_ type: UIColor.Type, forKey key: Key) throws -> UIColor {

        let colorHexString = try self.decode(String.self, forKey: key)
        let color = UIColor(hexString: colorHexString)

        return color
    }
}

要执行此操作，我需要通过手动解码容器并对其进行解码，但是由于我有很多配置，因此我的课程非常庞大，因为我需要设置所有内容：

For this to work i need to decode it manually by getting the container and decode it, but since i have alot of configurations my class will be huge because i need to set everything:

struct Settings: Decodable {

    var color: Color

    enum CodingKeys: CodingKey {

        case color
    }

   init(from decoder: Decoder) throws {

        let container = try decoder.container(keyedBy: CodingKeys.self)

        color = try container.decode(UIColor.self, forKey: .color)
   }
}

最终im寻找一种更清洁的方法来执行此操作。理想的方法是将UIColor设置为可编码（但我认为我不能做到这一点）

In the end im looking for a much cleaner way to do this. The ideal way is to turn UIColor codable (but i think i cant do that)

预先感谢

推荐答案

我要解决此问题的方法是引入一种新的 Color 类型，该类型符合 Decodable 协议并包装单个 UIColor 属性：

What I did to solve this problem is to introduce a new Color type that conforms to the Decodable protocol and wraps a single UIColor property:

struct Color : Decodable {
    let value: UIColor

    init(from decoder: Decoder) throws {
        let container = try decoder.singleValueContainer()
        let string = try container.decode(String.self)
        self.value = try UIColor(rgba_throws: string) // From https://github.com/yeahdongcn/UIColor-Hex-Swift
    }
}

然后您将使用它：

cell.textLabel?.textColor = settings.color.value

仅适用于UIColor，如果您希望使其适用于不符合Decoda的任何类型作为一种协议，John Sundell在在Swift中自定义可编码类型中描述了一种通用方法。

That's for UIColor only, if you want to make it work for any type that doesn't conform to the Decodable protocol, John Sundell describes a generic approach in Customizing Codable types in Swift.

这篇关于使用Codable（Swift）从Json文件解析UIColor的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！