问题
I would like to be able to save a Custom-struct to UserDefaults but for that I need it to be Codable.. I tried it like this:
struct Wishlist: Codable {
var name: String
var image: UIImage
var wishData: [Wish]
var color: UIColor
var textColor: UIColor
var index: Int
}
But that gives me this error:
Type 'Wishlist' does not conform to protocol 'Decodable'
Here is my Class Wish , maybe that's where the problem is:
class Wish: NSObject {
public var wishName : String?
public var checkedStatus : Bool?
public var wishLink : String?
public var wishPrice : String?
public var wishNote : String?
public var wishImage : UIImage?
init(withWishName name: String, link: String, price: String, note: String, image: UIImage, checked: Bool) {
super.init()
wishName = name
checkedStatus = checked
wishLink = link
wishPrice = price
wishNote = note
wishImage = image
}
}
What am I doing wrong here??
回答1:
You will need to make Wish adopt Codable.
But because UIImage and UIColor are not Codable, you’ll have to manually implement them as outlined in Encoding and Decoding Custom Types:
struct Wishlist: Codable {
var name: String
var image: UIImage
var wishes: [Wish]
var color: UIColor
var textColor: UIColor
var index: Int
enum CodingKeys: String, CodingKey {
case name, image, wishData, color, textColor, index
}
init(name: String, image: UIImage, wishes: [Wish], color: UIColor, textColor: UIColor, index: Int) {
self.name = name
self.image = image
self.wishes = wishes
self.color = color
self.textColor = textColor
self.index = index
}
init(from decoder: Decoder) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
name = try values.decode(String.self, forKey: .name)
wishes = try values.decode([Wish].self, forKey: .wishData)
color = try values.decode(Color.self, forKey: .color).uiColor
textColor = try values.decode(Color.self, forKey: .textColor).uiColor
index = try values.decode(Int.self, forKey: .index)
let data = try values.decode(Data.self, forKey: .image)
guard let image = UIImage(data: data) else {
throw DecodingError.dataCorruptedError(forKey: .image, in: values, debugDescription: "Invalid image data")
}
self.image = image
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(name, forKey: .name)
try container.encode(wishes, forKey: .wishData)
try container.encode(Color(uiColor: color), forKey: .color)
try container.encode(Color(uiColor: textColor), forKey: .textColor)
try container.encode(index, forKey: .index)
try container.encode(image.pngData(), forKey: .image)
}
}
struct Wish: Codable {
public var name: String
public var checkedStatus: Bool
public var link: String
public var price: String
public var note: String
public var image: UIImage
init(name: String, link: String, price: String, note: String, image: UIImage, checkedStatus: Bool) {
self.name = name
self.checkedStatus = checkedStatus
self.link = link
self.price = price
self.note = note
self.image = image
}
enum CodingKeys: String, CodingKey {
case name, checkedStatus, link, price, note, image
}
init(from decoder: Decoder) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
name = try values.decode(String.self, forKey: .name)
checkedStatus = try values.decode(Bool.self, forKey: .checkedStatus)
link = try values.decode(String.self, forKey: .link)
price = try values.decode(String.self, forKey: .price)
note = try values.decode(String.self, forKey: .note)
let data = try values.decode(Data.self, forKey: .image)
guard let image = UIImage(data: data) else {
throw DecodingError.dataCorruptedError(forKey: .image, in: values, debugDescription: "Invalid image data")
}
self.image = image
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(name, forKey: .name)
try container.encode(checkedStatus, forKey: .checkedStatus)
try container.encode(link, forKey: .link)
try container.encode(price, forKey: .price)
try container.encode(note, forKey: .note)
try container.encode(image.pngData(), forKey: .image)
}
}
Where I’d use this as a convenient way to encode UIColor objects:
struct Color: Codable {
let red: CGFloat
let green: CGFloat
let blue: CGFloat
let alpha: CGFloat
init(red: CGFloat, green: CGFloat, blue: CGFloat, alpha: CGFloat) {
self.red = red
self.green = green
self.blue = blue
self.alpha = alpha
}
init(uiColor: UIColor) {
var red: CGFloat = 0
var green: CGFloat = 0
var blue: CGFloat = 0
var alpha: CGFloat = 0
uiColor.getRed(&red, green: &green, blue: &blue, alpha: &alpha)
self.red = red
self.green = green
self.blue = blue
self.alpha = alpha
}
var uiColor: UIColor { UIColor(red: red, green: green, blue: blue, alpha: alpha) }
}
Note, I did a couple of unrelated changes:
I made both of these
struct. I wouldn’t introduce reference types (much lessNSObjectsubclasses) unless necessary.I simplified some of the property names. E.g. in
Wish, we wouldn’t generally usewishprefix in property names. I also wouldn’t use “data” in a property name unless it was, in fact, aData.I updated
initmethods to use standard naming conventions.
回答2:
Also your class Wish have to implement Codable protocol
回答3:
UIImage does not conform to Codable. You could convert it to Base64 first and then store that in UserDefaults.
回答4:
I got the same error before, but then I realized that the CodingKey doesn't match with the struct. or there is Any Data type, just change the data type to your custom object.
for example:
public struct DtClip: Codable {
// MARK: Properties
public var video: String?
public var preview: String?
public var clip: String?
public var trailer: String?
enum CodingKeys: String, CodingKey {
case video = "video"
case preview = "preview"
case clip = "clip"
}
}
from the example we know that trailer isn't in the codingKeys yet. You should add it to CodingKeys too.
public struct DtClip: Codable {
// MARK: Properties
public var video: String?
public var preview: String?
public var clip: String?
public var trailer: Any?
enum CodingKeys: String, CodingKey {
case video = "video"
case preview = "preview"
case clip = "clip"
}
}
from the second example, Any should be changed to another data type like String, Int, or Trailer (custom data type).
来源：https://stackoverflow.com/questions/61548074/custom-struct-type-does-not-conform-to-protocol-decodable