如何使用 NSUserDefaults 将自定义数组类存储在 Swift 中？

Question

我有一个名为 Person 的自定义 class，它会在某人输入信息时存储有关他们的各种属性。

class Person {

    // Person dictionary variable
    var name: String?
    var age: String?
    var html_url: String?

    init(json: NSDictionary) { // Dictionary object
        self.name = json["name"] as? String
        self.age = json["age"] as? String
        self.html_url = json["html_url"] as? String // Location of the JSON file
    }
}

创建字典后，会将其放入数组中。点击按钮时，我无法将数组保存到 NSUserDefaults。

personArray.append(newPerson) // newPerson = dictionary of attributes


NSUserDefaults.standardUserDefaults().setObject(personArray, forKey: "personArray")
        NSUserDefaults.standardUserDefaults().synchronize()

我看过 How to store custom objects in NSUserDefaults and Saving custom SWIFT class with NSCoding to UserDefaults，但我没有运气，而且我发现它很难理解。

当我只是尝试保存到 NSUserDefaults 时，我被告知如下：

Attempt to set a non-property-list object (
    "PersonApp.Person"
) as an NSUserDefaults/CFPreferences value for key personArray

谁能帮我通过 NSUserDefaults 实际保存一组自定义对象（自定义词典）？

Answer 1

您需要实施 NSCoding 协议才能将自定义对象存储到 NSUserDefaults。看看这个例子 http://nshipster.com/nscoding/

Answer 2

你的人 class 应该是这样的：

Swift 3:

class Person : NSObject, NSCoding{

    // Person dictionary variable
    var name: String?
    var age: String?
    var html_url: String?

    init(json: NSDictionary) { // Dictionary object
        self.name = json["name"] as? String
        self.age = json["age"] as? String
        self.html_url = json["html_url"] as? String // Location of the JSON file
    }

    required init?(coder aDecoder: NSCoder) {

        self.name = aDecoder.decodeObjectForKey("name") as? String;
        self.age = aDecoder.decodeObjectForKey("age") as? String;
        self.html_url = aDecoder.decodeObjectForKey("html") as? String;
    }

    func encodeWithCoder(aCoder: NSCoder) {
        aCoder.encodeObject(self.name, forKey: "name");
        aCoder.encodeObject(self.age, forKey: "age");
        aCoder.encodeObject(self.html_url, forKey: "html");
    }
}

这里有一个从 NSUserDefaults 保存和检索数组的示例：

let p = Person()
p.name = "person1"
p.age = "12"
p.html_url = "www.google.ro"

let p2 = Person()
p2.name = "person2"
p2.age = "11"
p2.html_url = "www.google.ro"

let array = [p, p2]

let userDefaults = NSUserDefaults.standardUserDefaults()
userDefaults.setValue(NSKeyedArchiver.archivedDataWithRootObject(array), forKey: "persons")
userDefaults.synchronize()

let array : [Person]
array = NSKeyedUnarchiver.unarchiveObjectWithData(userDefaults.objectForKey("persons") as! NSData) as! [Person]
print("\(array[0].name)\(array[1].name)")

Swift 4:

class Person : NSObject, NSCoding{

    // Person dictionary variable
    var name: String?
    var age: String?
    var html_url: String?

    init(json: NSDictionary) { // Dictionary object
        self.name = json["name"] as? String
        self.age = json["age"] as? String
        self.html_url = json["html_url"] as? String // Location of the JSON file
    }

    required init?(coder aDecoder: NSCoder) {
        self.name = aDecoder.decodeObject(forKey: "name") as? String;
        self.age = aDecoder.decodeObject(forKey: "age") as? String;
        self.html_url = aDecoder.decodeObject(forKey: "html") as? String;
    }

    func encode(with aCoder: NSCoder) {
        aCoder.encode(self.name, forKey: "name");
        aCoder.encode(self.age, forKey: "age");
        aCoder.encode(self.html_url, forKey: "html");
    }
}

Answer 3

Swift 4

确认您的 class
使用 JsonEncoder 序列化（数据）您的对象 class
现在将您的数据保存到 userDefaults

查看此答案以获得清晰的思路

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