Hello,

I'm having problems getting data back from documents directory to show it in my List. Saving function seems to be working fine:

func saveData(name: String, id: UUID, image: UIImage) {
        let idString = String("\(id)")
        do {
            try name.write(to: url, atomically: true, encoding: .utf8)
            try idString.write(to: url, atomically: true, encoding: .utf8)
            if let jpegData = image.jpegData(compressionQuality: 0.8) {
                try? jpegData.write(to: url, options: [.atomic, .completeFileProtection])
            }
        } catch {
            print(error.localizedDescription)
        }
    }

However, when i try to loadData, it shows me an error: dataCorrupted(Swift.DecodingError.Context(codingPath: [], debugDescription: "The given data was not valid JSON.", underlyingError: Optional(Error Domain=NSCocoaErrorDomain Code=3840 "Garbage at end around line 1, column 3." UserInfo={NSDebugDescription=Garbage at end around line 1, column 3., NSJSONSerializationErrorIndex=3})))

This is the loadData function.

func loadData() {
        do {
            let data = try Data(contentsOf: savePath)
            persons = try JSONDecoder().decode([Person].self, from: data)
        } catch {
            print(String(describing: error))
            persons = []
        }
    }

What could be the problem? Does my saving function doesn't save data properly?

Here is my Person structure:

struct Person: Codable, Identifiable, Comparable {
    enum CodingKeys: CodingKey {
        case id, name, image
    }

    let savePath = FileManager.documentsDirectory.appendingPathComponent("ImageContext")

    let id: UUID
    var name: String
    var image: UIImage

    static func < (lhs: Person, rhs: Person) -> Bool {
        lhs.name < rhs.name
    }

    init(id: UUID, name: String, image: UIImage) {
        self.id = id
        self.name = name
        self.image = image
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)

        id = try container.decode(UUID.self, forKey: .id)
        name = try container.decode(String.self, forKey: .name)

        let imageData = try container.decode(Data.self, forKey: .image)
        let decodedImage = UIImage(data: imageData) ?? UIImage()
        self.image = decodedImage
    }

    func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(id, forKey: .id)
        try container.encode(name, forKey: .name)
        if let jpegData = image.jpegData(compressionQuality: 0.8) {
            try? jpegData.write(to: savePath, options: [.atomic, .completeFileProtection])
            try container.encode(jpegData, forKey: .image)
        }
    }
}

It looks like you are not encoding the data before saving. Your save fuction is saving over the same file "url" 3 times.

@Fly0strich Thank you, the problem with saving function was that i didn't encode it, you're right. But that was not the only thing - i had a lot of unnecessary stuff there which caused to save stuff as dictionary, not array of all people. I commented out the unnecessary stuff and now everything is working fine! :)

Here is the final code that is giving me the expected outcome.

func saveData(/*name: String, id: UUID, image: UIImage*/) {
        // let newPerson = Person(id: id, name: name, image: image)
        do {
            let data = try JSONEncoder().encode(persons)
            try data.write(to: url, options: [.atomic])
            /*if let jpegData = image.jpegData(compressionQuality: 0.8) {
                try? jpegData.write(to: url, options: .atomic)
            }*/
            print("Data saved to URL: \(url)")
        } catch {
            print(error.localizedDescription)
        }
    }

func loadData() {
        do {
            let data = try Data(contentsOf: savePath)
            persons = try JSONDecoder().decode([Person].self, from: data)
        } catch {
            print(String(describing: error))
            persons = []
        }
    }