我有一个对象数组,每个对象都有许多属性。以下是循环遍历对象数组的一些示例数据:
Name = Rent
Default Value 750
This Months Estimate = 750
Sum Of This Months Actuals = 0
Risk Factor = 0.0
Monthly Average = 750.0
--------------
Name = Bills
Default Value 250
This Months Estimate = 170
Sum Of This Months Actuals = 140
Risk Factor = 0.0
Monthly Average = 190.0
--------------
Name = Food
Default Value 240
This Months Estimate = 200
Sum Of This Months Actuals = 95
Risk Factor = 0.0
Monthly Average = 190.0
--------------
Name = Lunches
Default Value 100
This Months Estimate = 150
Sum Of This Months Actuals = 155
Risk Factor = 0.899999976158142
Monthly Average = 190.0
它的数据很少,所以我想避免使用核心数据。我需要能够持久保存数组然后再次打开它并能够循环它。我希望使用一个简单的解决方案,如NSUserDefaults或NSKeyedArchiver,但在Swift中,我既不能使用这种类型的数组(我已经在线阅读文档和论坛和示例24小时了......)
你会如何推荐我坚持保存像上面这样的对象数组?或者可能坚持保存这种类型的数组是不好的做法?
在此先感谢您的帮助!
添加对象类:
class costCategory : NSObject {
var name : String
var defaultValue : Int
var thisMonthsEstimate : Int
var sumOfThisMonthsActuals : Int
var riskFactor : Float
var monthlyAverage : Float
init (name:String, defaultValue:Int, thisMonthsEstimate:Int, sumOfThisMonthsActuals:Int, riskFactor:Float, monthlyAverage:Float) {
self.name = name
self.defaultValue = defaultValue
self.thisMonthsEstimate = thisMonthsEstimate
self.sumOfThisMonthsActuals = sumOfThisMonthsActuals
self.riskFactor = riskFactor
self.monthlyAverage = monthlyAverage
}
}
如果我尝试将数组保存到NSUserDefaults我收到错误:
Property list invalid for format: 200 (property lists cannot contain objects of type 'CFType')
我尝试过使用NSCoder类继承,但是我得到了一个无法解决的错误,如下所示:
class costCategory : NSObject, NSCoder {
var name : String
var defaultValue : Int
var thisMonthsEstimate : Int
var sumOfThisMonthsActuals : Int
var riskFactor : Float
var monthlyAverage : Float
init (name:String, defaultValue:Int, thisMonthsEstimate:Int, sumOfThisMonthsActuals:Int, riskFactor:Float, monthlyAverage:Float) {
self.name = name
self.defaultValue = defaultValue
self.thisMonthsEstimate = thisMonthsEstimate
self.sumOfThisMonthsActuals = sumOfThisMonthsActuals
self.riskFactor = riskFactor
self.monthlyAverage = monthlyAverage
}
// MARK: NSCoding
required convenience init(coder decoder: NSCoder) {
self.init() //Error here "missing argument for parameter name in call
self.name = decoder.decodeObjectForKey("name") as String
self.defaultValue = decoder.decodeIntegerForKey("defaultValue")
self.thisMonthsEstimate = decoder.decodeIntegerForKey("thisMonthsEstimate")
self.sumOfThisMonthsActuals = decoder.decodeIntegerForKey("sumOfThisMonthsActuals")
self.riskFactor = decoder.decodeFloatForKey("riskFactor")
self.monthlyAverage = decoder.decodeFloatForKey("monthlyAverage")
}
func encodeWithCoder(coder: NSCoder) {
coder.encodeObject(self.name, forKey: "name")
coder.encodeInt(Int32(self.defaultValue), forKey: "defaultValue")
coder.encodeInt(Int32(self.thisMonthsEstimate), forKey: "thisMonthsEstimate")
coder.encodeInt(Int32(self.sumOfThisMonthsActuals), forKey: "sumOfThisMonthsActuals")
coder.encodeFloat(self.riskFactor, forKey: "riskFactor")
coder.encodeFloat(self.monthlyAverage, forKey: "monthlyAverage")
}
}
一种可能性是将对象属性:value转换为string:object将它们存储到NSUserDefaults
然后获取并解码它们。
如果你想使用NSKeyedArchiver
存储你的对象,你的类需要符合NSCoding
并且是NSObject
的子类。例:
class costCategory : NSObject, NSCoding {
var name : String
var defaultValue : Int
var thisMonthsEstimate : Int
var sumOfThisMonthsActuals : Int
var riskFactor : Float
var monthlyAverage : Float
init (name:String, defaultValue:Int, thisMonthsEstimate:Int, sumOfThisMonthsActuals:Int, riskFactor:Float, monthlyAverage:Float) {
self.name = name
self.defaultValue = defaultValue
self.thisMonthsEstimate = thisMonthsEstimate
self.sumOfThisMonthsActuals = sumOfThisMonthsActuals
self.riskFactor = riskFactor
self.monthlyAverage = monthlyAverage
}
// MARK: NSCoding
required init(coder decoder: NSCoder) {
//Error here "missing argument for parameter name in call
self.name = decoder.decodeObjectForKey("name") as String
self.defaultValue = decoder.decodeIntegerForKey("defaultValue")
self.thisMonthsEstimate = decoder.decodeIntegerForKey("thisMonthsEstimate")
self.sumOfThisMonthsActuals = decoder.decodeIntegerForKey("sumOfThisMonthsActuals")
self.riskFactor = decoder.decodeFloatForKey("riskFactor")
self.monthlyAverage = decoder.decodeFloatForKey("monthlyAverage")
super.init()
}
func encodeWithCoder(coder: NSCoder) {
coder.encodeObject(self.name, forKey: "name")
coder.encodeInt(Int32(self.defaultValue), forKey: "defaultValue")
coder.encodeInt(Int32(self.thisMonthsEstimate), forKey: "thisMonthsEstimate")
coder.encodeInt(Int32(self.sumOfThisMonthsActuals), forKey: "sumOfThisMonthsActuals")
coder.encodeFloat(self.riskFactor, forKey: "riskFactor")
coder.encodeFloat(self.monthlyAverage, forKey: "monthlyAverage")
}
}
然后你可以存档并保存到NSDefaults
:
let defaults = NSUserDefaults.standardUserDefaults()
let arrayOfObjectsKey = "arrayOfObjectsKey"
var arrayOfObjects = [costCategory]()
var arrayOfObjectsData = NSKeyedArchiver.archivedDataWithRootObject(arrayOfObjects)
defaults.setObject(arrayOfObjectsData, forKey: arrayOfObjectsKey)
// ...
var arrayOfObjectsUnarchivedData = defaults.dataForKey(arrayOfObjectsKey)!
var arrayOfObjectsUnarchived = NSKeyedUnarchiver.unarchiveObjectWithData(arrayOfObjectsUnarchivedData) as [costCategory]
核心数据非常强大,我强烈建议您不要被其令人生畏的外观所左右。当您的应用程序增长时,您会非常感激您使用Core Data支持您的数据,因为它的扩展性非常好。
话虽这么说,这是一篇关于NSHipster that covers the basics of using the NSKeyedArchiver的好文章。所以解决方案是让你的对象成为NSObject的子类并符合NSCoding协议。这允许您归档从磁盘中取消归档对象。您可以将文件保存到documents directory
然后你的子类需要隐式解包所有可编码变量,结果会产生:
class costCategory : NSObject, NSCoding {
var name : String!
var defaultValue : Int!
var thisMonthsEstimate : Int!
var sumOfThisMonthsActuals : Int!
var riskFactor : Float!
var monthlyAverage : Float!
init (name:String, defaultValue:Int, thisMonthsEstimate:Int, sumOfThisMonthsActuals:Int, riskFactor:Float, monthlyAverage:Float) {
self.name = name
self.defaultValue = defaultValue
self.thisMonthsEstimate = thisMonthsEstimate
self.sumOfThisMonthsActuals = sumOfThisMonthsActuals
self.riskFactor = riskFactor
self.monthlyAverage = monthlyAverage
}
override init() {
super.init()
}
// MARK: NSCoding
required convenience init(coder decoder: NSCoder) {
self.init()
self.name = decoder.decodeObjectForKey("name") as String
self.defaultValue = decoder.decodeIntegerForKey("defaultValue")
self.thisMonthsEstimate = decoder.decodeIntegerForKey("thisMonthsEstimate")
self.sumOfThisMonthsActuals = decoder.decodeIntegerForKey("sumOfThisMonthsActuals")
self.riskFactor = decoder.decodeFloatForKey("riskFactor")
self.monthlyAverage = decoder.decodeFloatForKey("monthlyAverage")
}
func encodeWithCoder(coder: NSCoder) {
coder.encodeObject(self.name, forKey: "name")
coder.encodeInteger((self.defaultValue), forKey: "defaultValue")
coder.encodeInteger((self.thisMonthsEstimate), forKey: "thisMonthsEstimate")
coder.encodeInteger((self.sumOfThisMonthsActuals), forKey: "sumOfThisMonthsActuals")
coder.encodeFloat(self.riskFactor, forKey: "riskFactor")
coder.encodeFloat(self.monthlyAverage, forKey: "monthlyAverage")
}
}
然后,您可以添加一种在文档目录中查找位置的方法:
func documentsDirectory() -> NSString {
let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
let documentDirectory = paths[0] as String
return documentDirectory
}
所以存档看起来像这样:
var filePath = documentsDirectory().stringByAppendingPathComponent("fileName")
NSKeyedArchiver.archiveRootObject(receipts, toFile: filePath)
以后你可以从磁盘读回你的数组:
let receipts = NSKeyedUnarchiver.unarchiveObjectWithFile(filePath)
我建议不要使用User Defaults来存储数组,它意味着存储首选项,这里看一下文档:
NSUserDefaults类提供了一个用于与默认系统交互的编程接口。默认系统允许应用程序自定义其行为以匹配用户的首选项。例如,您可以允许用户确定应用程序显示的度量单位或自动保存文档的频率。应用程序通过将值分配给用户默认数据库中的一组参数来记录此类首选项。
理想情况下,您不希望持久化数组,因为即使您需要一个对象,也必须将整个数组提取到内存中。自然核心数据将为你解决所有不必要的堆乱:)
编辑
为了让自己更容易进入核心数据,你可以随时查看Magical Record。它们简化了维护Core Data堆栈所需的大量工作。
祝好运
核心数据传播者