如何使用swift将对象数组保存到NSUserDefault？ [英] How to save an array of objects to NSUserDefault with swift?

问题描述

这是一个的地方我定义了：

class Place: NSObject {

    var latitude: Double
    var longitude: Double

    init(lat: Double, lng: Double, name: String){
        self.latitude = lat
        self.longitude = lng
    }

    required init(coder aDecoder: NSCoder) {
        self.latitude = aDecoder.decodeDoubleForKey("latitude")
        self.longitude = aDecoder.decodeDoubleForKey("longitude")
    }

    func encodeWithCoder(aCoder: NSCoder!) {
        aCoder.encodeObject(latitude, forKey: "latitude")
        aCoder.encodeObject(longitude, forKey: "longitude")
    }

}

这就是我试图保存数组的地方 s：

This is how I tried to save an array of Places:

var placesArray = [Place]

//...

func savePlaces() {
    NSUserDefaults.standardUserDefaults().setObject(placesArray, forKey: "places")
    println("place saved")
}

它没有工作，这是我在控制台上得到的：

It didn't work, this is what I get on the console:

Property list invalid for format: 200 (property lists cannot contain objects of type 'CFType')

我是iOS新手，你能帮助我吗？

I am new to iOS, could you help me ?

第二版

我找到了保存数据的解决方案：

I found a solution to save the data :

func savePlaces(){
    let myData = NSKeyedArchiver.archivedDataWithRootObject(placesArray)
   NSUserDefaults.standardUserDefaults().setObject(myData, forKey: "places")
    println("place saved")
}

但是在使用此代码加载数据时出现错误：

But I get an error when loading the data with this code :

 let placesData = NSUserDefaults.standardUserDefaults().objectForKey("places") as? NSData

 if placesData != nil {
      placesArray = NSKeyedUnarchiver.unarchiveObjectWithData(placesData!) as [Place]
 }

错误是：

[NSKeyedUnarchiver decodeDoubleForKey:]: value for key (latitude) is not a double number'

我很确定我存档了一个Double，保存/加载过程存在问题

I am pretty sure I archived a Double, there is an issue with the saving/loading process

任何线索？

推荐答案

来自属性列表编程指南：

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还原数据层次结构。

If a property-list object is a container (that is, an array or dictionary), all objects contained within it must also be property-list objects. If an array or dictionary contains objects that are not property-list objects, then you cannot save and restore the hierarchy of data using the various property-list methods and functions.

您需要将对象转换为 NSData 实例使用 NSKeyedArchiver 和 NSKeyedUnarchiver 。

You'll need to convert the object to and from an NSData instance using NSKeyedArchiver and NSKeyedUnarchiver.

例如：

func savePlaces(){
    let placesArray = [Place(lat: 123, lng: 123, name: "hi")]
    let placesData = NSKeyedArchiver.archivedDataWithRootObject(placesArray)
    NSUserDefaults.standardUserDefaults().setObject(placesData, forKey: "places")
}

func loadPlaces(){
    let placesData = NSUserDefaults.standardUserDefaults().objectForKey("places") as? NSData

    if let placesData = placesData {
        let placesArray = NSKeyedUnarchiver.unarchiveObjectWithData(placesData) as? [Place]

        if let placesArray = placesArray {
            // do something…
        }

    }
}

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