将 Set<CustomObject> 存储到 UserDefaults

Question

我有一个自定义 class，我将其用作 Set<ListItem>。我想将其存储到 userDefaults。但是，我在尝试时遇到 Attempt to set a non-property-list object as an NSUserDefaults 错误。我试图将其更改为 Array 然后保存，但仍然出现同样的错误。在看到一些帖子后，我也尝试了另存为数据，这又给了我以下错误。

NSForwarding: warning: object 0x600003bf9a00 of class 'iTunes_Search_Me.ListItem' does not implement methodSignatureForSelector: -- trouble ahead

class ListItem: Codable ,Equatable, Hashable {
    let wrapperType, kind: String?
    let artistID, collectionID, trackID: Int?
    let artistName, collectionName, trackName: String?
    let trackViewURL: String?
    let artworkUrl30, artworkUrl60, artworkUrl100: String?
    let releaseDate: String?
    let primaryGenreName: String?
    var isSelected: Bool = false
    enum CodingKeys: String, CodingKey {
        case wrapperType, kind
        case artistID
        case collectionID
        case trackID
        case artistName, collectionName, trackName
        case trackViewURL
        case artworkUrl30, artworkUrl60, artworkUrl100, releaseDate, primaryGenreName
    }

    static func ==(lhs: ListItem, rhs: ListItem) -> Bool {
        return lhs.trackID == rhs.trackID
    }

    func hash(into hasher: inout Hasher) {
        hasher.combine(trackID)
    }
}

Attempt to set a non-property-list object as an NSUserDefaults

Answer 1

您可以像这样将模型设置为 UserDefaults：

首先你应该创建一个模型的实例

然后您可以将模型保存到 UserDefaults:

let encoder = JSONEncoder()
if let encoded = try? encoder.encode(listItemInstance) {
    let defaults = UserDefaults.standard
    defaults.set(encoded, forKey: "ListItemObject")
}

您可以像这样从 UserDefaults 获取模型

if let savedItem = defaults.object(forKey: "ListItemObject") as? Data {
    let decoder = JSONDecoder()
    if let loadedItem = try? decoder.decode(ListItem.self, from: savedItem) {
        print(loadedItem)
    }
}

Answer 2

您可以先尝试设置保存的数据：

struct saveData{
   static let encoded = "encoded"
}

然后保存在那个键下：

UserDefaults.standard.set(encoded as! Data, forKey: "encoded")

或尝试将其另存为字符串。

将 Set<CustomObject> 存储到 UserDefaults

Storing Set<CustomObject> to UserDefaults

ios

arrays

swift

set

userdefaults