尝试将非属性列表对象设置为 NSUserDefaults

Question

我以为我知道是什么导致了这个错误，但我似乎无法弄清楚我做错了什么。

这是我收到的完整错误消息：

尝试设置非属性列表对象 ( “” ) 作为关键 personDataArray 的 NSUserDefaults 值

我有一个 Person 类，我认为它符合 NSCoding 协议，我的 person 类中同时拥有这两种方法：

- (void)encodeWithCoder:(NSCoder *)coder {
    [coder encodeObject:self.personsName forKey:@"BCPersonsName"];
    [coder encodeObject:self.personsBills forKey:@"BCPersonsBillsArray"];
}

- (id)initWithCoder:(NSCoder *)coder {
    self = [super init];
    if (self) {
        self.personsName = [coder decodeObjectForKey:@"BCPersonsName"];
        self.personsBills = [coder decodeObjectForKey:@"BCPersonsBillsArray"];
    }
    return self;
}

在应用程序的某个时刻，BC_PersonClass 中的 NSString 已设置，并且我有一个 DataSave 类，我认为它正在处理我的 BC_PersonClass 中的属性编码。 这是我在 DataSave 类中使用的代码：

- (void)savePersonArrayData:(BC_Person *)personObject
{
   // NSLog(@"name of the person %@", personObject.personsName);

    [mutableDataArray addObject:personObject];

    // set the temp array to the mutableData array
    tempMuteArray = [NSMutableArray arrayWithArray:mutableDataArray];

    // save the person object as nsData
    NSData *personEncodedObject = [NSKeyedArchiver archivedDataWithRootObject:personObject];

    // first add the person object to the mutable array
    [tempMuteArray addObject:personEncodedObject];

    // NSLog(@"Objects in the array %lu", (unsigned long)mutableDataArray.count);

    // now we set that data array to the mutable array for saving
    dataArray = [[NSArray alloc] initWithArray:mutableDataArray];
    //dataArray = [NSArray arrayWithArray:mutableDataArray];

    // save the object to NS User Defaults
    NSUserDefaults *userData = [NSUserDefaults standardUserDefaults];
    [userData setObject:dataArray forKey:@"personDataArray"];
    [userData synchronize];
}

我希望这些代码足以让您了解我想要做什么。 我再次知道我的问题在于我如何在我的 BC_Person 类中编码我的属性，我似乎无法弄清楚我做错了什么。

感谢您的帮助！

Answer 1

您发布的代码尝试将一组自定义对象保存到NSUserDefaults。你不能那样做。实现NSCoding 方法没有帮助。您只能在NSUserDefaults 中存储NSArray、NSDictionary、NSString、NSData、NSNumber 和NSDate 之类的内容。

您需要将对象转换为NSData（就像您在某些代码中所做的那样）并将该NSData 存储在NSUserDefaults 中。如果需要，您甚至可以存储 NSArray 或 NSData。

当您读回数组时，您需要取消归档 NSData 以取回您的 BC_Person 对象。

也许你想要这个：

- (void)savePersonArrayData:(BC_Person *)personObject {
    [mutableDataArray addObject:personObject];

    NSMutableArray *archiveArray = [NSMutableArray arrayWithCapacity:mutableDataArray.count];
    for (BC_Person *personObject in mutableDataArray) { 
        NSData *personEncodedObject = [NSKeyedArchiver archivedDataWithRootObject:personObject];
        [archiveArray addObject:personEncodedObject];
    }

    NSUserDefaults *userData = [NSUserDefaults standardUserDefaults];
    [userData setObject:archiveArray forKey:@"personDataArray"];
}

Answer 2

对我来说，自己遍历数组并将对象编码为 NSData 似乎相当浪费。您的错误 BC_Person is a non-property-list object 告诉您该框架不知道如何序列化您的 person 对象。

因此，只需确保您的 person 对象符合 NSCoding，您就可以简单地将您的自定义对象数组转换为 NSData 并将其存储为默认值。这是一个游乐场：

编辑：在 Xcode 7 上写入 NSUserDefaults 被破坏，因此 Playground 将归档到数据并返回并打印输出。包括 UserDefaults 步骤，以防它在以后修复

//: Playground - noun: a place where people can play

import Foundation

class Person: NSObject, NSCoding {
    let surname: String
    let firstname: String

    required init(firstname:String, surname:String) {
        self.firstname = firstname
        self.surname = surname
        super.init()
    }

    //MARK: - NSCoding -
    required init(coder aDecoder: NSCoder) {
        surname = aDecoder.decodeObjectForKey("surname") as! String
        firstname = aDecoder.decodeObjectForKey("firstname") as! String
    }

    func encodeWithCoder(aCoder: NSCoder) {
        aCoder.encodeObject(firstname, forKey: "firstname")
        aCoder.encodeObject(surname, forKey: "surname")
    }
}

//: ### Now lets define a function to convert our array to NSData

func archivePeople(people:[Person]) -> NSData {
    let archivedObject = NSKeyedArchiver.archivedDataWithRootObject(people as NSArray)
    return archivedObject
}

//: ### Create some people

let people = [Person(firstname: "johnny", surname:"appleseed"),Person(firstname: "peter", surname: "mill")]

//: ### Archive our people to NSData

let peopleData = archivePeople(people)

if let unarchivedPeople = NSKeyedUnarchiver.unarchiveObjectWithData(peopleData) as? [Person] {
    for person in unarchivedPeople {
        print("\(person.firstname), you have been unarchived")
    }
} else {
    print("Failed to unarchive people")
}

//: ### Lets try use NSUserDefaults
let UserDefaultsPeopleKey = "peoplekey"
func savePeople(people:[Person]) {
    let archivedObject = archivePeople(people)
    let defaults = NSUserDefaults.standardUserDefaults()
    defaults.setObject(archivedObject, forKey: UserDefaultsPeopleKey)
    defaults.synchronize()
}

func retrievePeople() -> [Person]? {
    if let unarchivedObject = NSUserDefaults.standardUserDefaults().objectForKey(UserDefaultsPeopleKey) as? NSData {
        return NSKeyedUnarchiver.unarchiveObjectWithData(unarchivedObject) as? [Person]
    }
    return nil
}

if let retrievedPeople = retrievePeople() {
    for person in retrievedPeople {
        print("\(person.firstname), you have been unarchived")
    }
} else {
    print("Writing to UserDefaults is still broken in playgrounds")
}

瞧，您已将一组自定义对象存储到 NSUserDefaults 中

Answer 3

首先，rmaddy 的回答（上面）是正确的：实现NSCoding 没有帮助。但是，您需要实现NSCoding 才能使用NSKeyedArchiver 和所有这些，所以这只是又一步......通过NSData 转换。

示例方法

- (NSUserDefaults *) defaults {
    return [NSUserDefaults standardUserDefaults];
}

- (void) persistObj:(id)value forKey:(NSString *)key {
    [self.defaults setObject:value  forKey:key];
    [self.defaults synchronize];
}

- (void) persistObjAsData:(id)encodableObject forKey:(NSString *)key {
    NSData *data = [NSKeyedArchiver archivedDataWithRootObject:encodableObject];
    [self persistObj:data forKey:key];
}    

- (id) objectFromDataWithKey:(NSString*)key {
    NSData *data = [self.defaults objectForKey:key];
    return [NSKeyedUnarchiver unarchiveObjectWithData:data];
}

因此，您可以将 NSCoding 对象包装在 NSArray 或 NSDictionary 或其他任何东西中......

Answer 4

保存：

NSUserDefaults *currentDefaults = [NSUserDefaults standardUserDefaults];
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:yourObject];
[currentDefaults setObject:data forKey:@"yourKeyName"];

获取：

NSData *data = [currentDefaults objectForKey:@"yourKeyName"];
yourObjectType * token = [NSKeyedUnarchiver unarchiveObjectWithData:data];

删除

[currentDefaults removeObjectForKey:@"yourKeyName"];

Answer 5

我在尝试将字典保存到 NSUserDefaults 时遇到了这个问题。事实证明它不会保存，因为它包含 NSNull 值。所以我只是将字典复制到一个可变字典中删除了空值然后保存到NSUserDefaults

NSMutableDictionary* dictionary = [NSMutableDictionary dictionaryWithDictionary:dictionary_trying_to_save];
[dictionary removeObjectForKey:@"NullKey"];
[[NSUserDefaults standardUserDefaults] setObject:dictionary forKey:@"key"];

在这种情况下，我知道哪些键可能是 NSNull 值。

Answer 6

Swift 3 解决方案

简单实用类

class ArchiveUtil {

    private static let PeopleKey = "PeopleKey"

    private static func archivePeople(people : [Human]) -> NSData {

        return NSKeyedArchiver.archivedData(withRootObject: people as NSArray) as NSData
    }

    static func loadPeople() -> [Human]? {

        if let unarchivedObject = UserDefaults.standard.object(forKey: PeopleKey) as? Data {

            return NSKeyedUnarchiver.unarchiveObject(with: unarchivedObject as Data) as? [Human]
        }

        return nil
    }

    static func savePeople(people : [Human]?) {

        let archivedObject = archivePeople(people: people!)
        UserDefaults.standard.set(archivedObject, forKey: PeopleKey)
        UserDefaults.standard.synchronize()
    }

}

模型类

class Human: NSObject, NSCoding {

    var name:String?
    var age:Int?

    required init(n:String, a:Int) {

        name = n
        age = a
    }


    required init(coder aDecoder: NSCoder) {

        name = aDecoder.decodeObject(forKey: "name") as? String
        age = aDecoder.decodeInteger(forKey: "age")
    }


    public func encode(with aCoder: NSCoder) {

        aCoder.encode(name, forKey: "name")
        aCoder.encode(age, forKey: "age")

    }
}

如何调用

var people = [Human]()

people.append(Human(n: "Sazzad", a: 21))
people.append(Human(n: "Hissain", a: 22))
people.append(Human(n: "Khan", a: 23))

ArchiveUtil.savePeople(people: people)

let others = ArchiveUtil.loadPeople()

for human in others! {

    print("name = \(human.name!), age = \(human.age!)")
}

Answer 7

https://developer.apple.com/reference/foundation/userdefaults

默认对象必须是一个属性列表——即，NSData、NSString、NSNumber、NSDate、NSArray 或 NSDictionary 的实例（或集合的实例组合）。

如果要存储任何其他类型的对象，通常应该将其归档以创建 NSData 的实例。有关详细信息，请参阅首选项和设置编程指南。

Answer 8

Swift-4 Xcode 9.1

试试这个代码

不能在 NSUserDefault 中存储 mapper，只能存储 NSData、NSString、NSNumber、NSDate、NSArray 或 NSDictionary。

let myData = NSKeyedArchiver.archivedData(withRootObject: myJson)
UserDefaults.standard.set(myData, forKey: "userJson")

let recovedUserJsonData = UserDefaults.standard.object(forKey: "userJson")
let recovedUserJson = NSKeyedUnarchiver.unarchiveObject(with: recovedUserJsonData)

Answer 9

Swift 5非常简单的方法

//MARK:- First you need to encoded your arr or what ever object you want to save in UserDefaults
//in my case i want to save Picture (NMutableArray) in the User Defaults in
//in this array some objects are UIImage & Strings

//first i have to encoded the NMutableArray 
let encodedData = NSKeyedArchiver.archivedData(withRootObject: yourArrayName)
//MARK:- Array save in UserDefaults
defaults.set(encodedData, forKey: "YourKeyName")

//MARK:- When you want to retreive data from UserDefaults
let decoded  = defaults.object(forKey: "YourKeyName") as! Data
yourArrayName = NSKeyedUnarchiver.unarchiveObject(with: decoded) as! NSMutableArray

//MARK: Enjoy this arrry "yourArrayName"

Answer 10

Swift 5：可以使用 Codable 协议代替 NSKeyedArchiever。

struct User: Codable {
    let id: String
    let mail: String
    let fullName: String
}

Pref 结构是围绕 UserDefaults 标准对象的自定义包装器。

struct Pref {
    static let keyUser = "Pref.User"
    static var user: User? {
        get {
            if let data = UserDefaults.standard.object(forKey: keyUser) as? Data {
                do {
                    return try JSONDecoder().decode(User.self, from: data)
                } catch {
                    print("Error while decoding user data")
                }
            }
            return nil
        }
        set {
            if let newValue = newValue {
                do {
                    let data = try JSONEncoder().encode(newValue)
                    UserDefaults.standard.set(data, forKey: keyUser)
                } catch {
                    print("Error while encoding user data")
                }
            } else {
                UserDefaults.standard.removeObject(forKey: keyUser)
            }
        }
    }
}

所以你可以这样使用它：

Pref.user?.name = "John"

if let user = Pref.user {...

Answer 11

Swift 与 @propertyWrapper

将Codable对象保存到UserDefault

@propertyWrapper
    struct UserDefault<T: Codable> {
        let key: String
        let defaultValue: T

        init(_ key: String, defaultValue: T) {
            self.key = key
            self.defaultValue = defaultValue
        }

        var wrappedValue: T {
            get {

                if let data = UserDefaults.standard.object(forKey: key) as? Data,
                    let user = try? JSONDecoder().decode(T.self, from: data) {
                    return user

                }

                return  defaultValue
            }
            set {
                if let encoded = try? JSONEncoder().encode(newValue) {
                    UserDefaults.standard.set(encoded, forKey: key)
                }
            }
        }
    }




enum GlobalSettings {

    @UserDefault("user", defaultValue: User(name:"",pass:"")) static var user: User
}

示例用户模型确认可编码

struct User:Codable {
    let name:String
    let pass:String
}

如何使用

//Set value 
 GlobalSettings.user = User(name: "Ahmed", pass: "Ahmed")

//GetValue
print(GlobalSettings.user)

Answer 12

我遇到了这个问题，最终发现这是因为我试图使用NSNumber 作为字典键，而属性列表只允许字符串作为键。 setObject:forKey: 的文档没有提到这个限制，但它链接到的 About Property Lists 页面确实：

按照惯例，表 2-1 中列出的每个 Cocoa 和 Core Foundation 对象都称为属性列表对象。从概念上讲，您可以将“属性列表”视为所有这些类的抽象超类。如果您从某个方法或函数接收到一个属性列表对象，您就知道它必须是这些类型之一的实例，但您可能不知道先验是哪种类型。如果属性列表对象是容器（即数组或字典），则其中包含的所有对象也必须是属性列表对象。如果数组或字典包含不是属性列表对象的对象，则无法使用各种属性列表方法和函数保存和恢复数据层次结构。尽管 NSDictionary 和 CFDictionary 对象允许它们的键是任何类型的对象，如果键不是字符串对象，则集合不是属性列表对象。

（强调我的）