Question

我是编程新手。我在swift中为iOS制作了一个小数据库程序。

我有一个人类：

class Person : NSObject {
    var firstName : String
    var lastName : String

    init (firstName : String, lastName : String) {
        self.firstName = firstName
        self.lastName = lastName
    }
}

我在视图控制器的顶部声明了一个类的数组：

    var peopleArray = [Person]()

然后我通过声明一些示例用户并将其附加到数组来填充数组：

    var nateB = Person(firstName: "Nate", lastName: "Birkholz")
    var nateC = Person(firstName: "Nate", lastName: "Carson")
    var nateD = Person(firstName: "Nate", lastName: "Donnelly")
    self.peopleArray.append(nateB)
    self.peopleArray.append(nateC)
    self.peopleArray.append(nateD)

然后我尝试将数据保存到plist文件中：

        let fileManager = (NSFileManager.defaultManager())
        let directorys : [String]? = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory,NSSearchPathDomainMask.AllDomainsMask, true) as? [String]

        if (directorys != nil){
            let directories:[String] = directorys!;
            let pathToFile = directories[0]; //documents directory
            let plistfile = "PeopleArray.plist"
            let plistpath = pathToFile.stringByAppendingPathComponent(plistfile);

            if !fileManager.fileExistsAtPath(plistpath){ 

                println("Declaring cocoaArray")
                var cocoaArray : NSArray = peopleArray
                cocoaArray.writeToFile(plistpath, atomically: true)
            println("I wrote an array to the file at\n\n\(plistpath)")
            }

没有创建plist文件，它默默地无法创建，并且该函数完成就好了。有什么想法吗？

swift数据类型和数据结构与cocoa类的模糊兼容性过程令我感到沮丧。我只想保存一个危险文件。如果我将我的数组声明为NSArray，我也不能使用“append”函数，也不能+ +项目中的项目...

更新：

我在Person类中添加了以下函数：

func encodeWithCoder(aCoder: NSCoder!) {
    aCoder.encodeObject(firstName, forKey:"firstName")
    aCoder.encodeObject(lastName, forKey:"lastName")
}

init (coder aDecoder: NSCoder!) {
    self.firstName = aDecoder.decodeObjectForKey("firstName") as String
    self.lastName = aDecoder.decodeObjectForKey("lasName") as String
}

现在保存文件：

let fileManager = (NSFileManager.defaultManager())
        let directorys : [String]? = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory,NSSearchPathDomainMask.AllDomainsMask, true) as? [String]

        println("value of directorys is \(directorys)")

        if (directorys != nil){
            let directories:[String] = directorys!;
            let pathToFile = directories[0]; //documents directory

            let plistfile = "PeopleArray.plist"
            let plistpath = pathToFile.stringByAppendingPathComponent(plistfile);

            if !fileManager.fileExistsAtPath(plistpath){  //writing Plist file

                self.createInitialPeople()

                println("Declaring cocoaArray")
                var cocoaArray : NSArray = [NSKeyedArchiver.archivedDataWithRootObject(peopleArray)]
                println("writing to path")
                cocoaArray.writeToFile(plistpath, atomically: true)
                let tellMe = cocoaArray.writeToFile(plistpath, atomically: true)
                println("Return of write is \(tellMe)")
            }

创建具有不可知数据的Plist文件。

我关闭应用程序并再次启动它，然后尝试加载文件：

         else {            //Reading Plist file
            println("\n\nPlist file found at \(plistpath)")

            let cocoaArray = NSMutableArray.arrayWithContentsOfFile(plistpath)

            peopleArray = cocoaArray as Array
        }
    }

我失败了，因为我不能贬低“AnyObject与'人'不相同。我曾试图以多种方式向下转发它，但却无法成功。这真的令人沮丧。

Answer 1

将以下函数添加到Person类后：

func encodeWithCoder(aCoder: NSCoder!) {
    aCoder.encodeObject(firstName, forKey:"firstName")
    aCoder.encodeObject(lastName, forKey:"lastName")
}


init (coder aDecoder: NSCoder!) {
    self.firstName = aDecoder.decodeObjectForKey("firstName") as String
    self.lastName = aDecoder.decodeObjectForKey("lasName") as String
}

您应该使用【NSKeyedArchiver】和【NSKeyedUnarchiver】来存储和获取数组。

谢谢 @Anthony Kong 。

他的回答很有帮助，但我认为以下代码可以真正解决问题。

存放在阵列中的阵列

let paths = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory,NSSearchPathDomainMask.AllDomainsMask, true)
let path: AnyObject = paths[0]
let arrPath = path.stringByAppendingString("/array.plist")
NSKeyedArchiver.archiveRootObject(peopleArray, toFile: arrPath)

启动阵列形式列表

if let tempArr: [Person] = NSKeyedUnarchiver.unarchiveObjectWithFile(arrPath) as? [Person] {
    peopleArray = tempArr
}

Answer 2

首先，根本原因是[NSArray writeToFile:atomically:]仅支持某些数据类型。您可以查看文档here。

如果您打印cocoaArray.writeToFile(plistpath, atomically: true)的返回代码，您会看到它设置为False。

要克服此限制，您需要

1）在Person类

中实现编码功能

func encodeWithCoder(aCoder: NSCoder!) {
    aCoder.encodeObject(firstName, forKey:"firstName")
    aCoder.encodeObject(lastName, forKey:"lastName")
}

2）将数组中的元素转换为NSData，例如

   var cocoaArray : NSArray = [NSKeyedArchiver.archivedDataWithRootObject(nateB)]

最后，您还需要Person类中的解码函数来支持从plist文件中读取它们

iOS Swift：保存一组自定义类

2 个答案: