Question

我有一个名为Person的自定义类，可以在输入信息时存储有关某人的各种属性。

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，将其放入数组中。点击按钮时，我在将数组保存到NSUserDefaults时遇到问题。

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和Saving custom SWIFT class with NSCoding to UserDefaults，但我没有运气，发现很难理解。

当我只是尝试保存到NSUserDefaults时，我被告知以下内容：

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

有人能通过NSUserDefaults帮我实际保存一系列自定义对象（自定义词典）吗？

Answer 1

您的Person类应如下所示：

斯威夫特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保存和检索数组的例子：

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 2

您需要实施NSCoding协议才能将自定义对象存储到NSUserDefaults中。请查看此示例http://nshipster.com/nscoding/

Answer 3

Swift 4

确认您班级的可编码协议
使用JsonEncoder类
现在将您的数据保存到userDefaults

请参阅此答案以获得清晰的想法 Save Array of Custom Swift object to userDefaults

如何使用NSUserDefaults在Swift中存储自定义类的数组？

3 个答案: