读写应用程序数据-NSUserDefault、对象归档（NSKeyedArchiver）、文件操作

ios中数据持久化存储方式一般有5种：NSUserDefault、对象归档（NSKeyedArchiver）、文件操作、数据库存储（SQLite3）、CoreData。

1、NSUserDefault用于保存程序相关的偏好设置和配置数据等，以便下次启动程序后能恢复上次的设置。

NSUserDefault和对象归档

//通过单利来创建一个NSUserDefaults对象，全局变量NSUserDefault，可在整个项目传递变量
let userDefault:NSUserDefaults = NSUserDefaults.standardUserDefaults()

//通过init方法创建
let userDefault1:NSUserDefaults = NSUserDefaults(suiteName: "SwiftClass")!
print(userDefault1.dictionaryRepresentation())

//获取userDefault单利下所有的值
print(userDefault.dictionaryRepresentation())

//判断NSUserDefaults的“appMessage”key 在dictionaryRepresentation中是否存在，如果不存在就设置“appMessage”值为This is app message。
if(userDefault.objectForKey("message") == nil){
userDefault.setObject("This_is_my_default_message", forKey: "message")
}

//如果想单独看某个key的设置，例如:
let dic = userDefault.dictionaryRepresentation()
let object_one:AnyObject? = (dic as NSDictionary).objectForKey("AppleKeyboards")
//        //或者
//        var object_one:AnyObject?  = dic["AppleKeyboards"]

if let oValue: AnyObject! = object_one {
print(oValue)
}

//Int类型
//设置
userDefault.setInteger(123456, forKey: "Int")
//读取
let intValue = userDefault.integerForKey("Int")
print(intValue)

//Float类型
//设置
userDefault.setFloat(3.2, forKey: "Float")
//读取
let floatValue = userDefault.floatForKey("Float")
print(floatValue)

//Double类
//设置
userDefault.setDouble(5.6890, forKey: "Double")
//读取
let doubleValue = userDefault.doubleForKey("Double")
print(doubleValue)

//Bool类型
//设置
userDefault.setBool(true, forKey: "Bool")
//读取
let boolValue = userDefault.boolForKey("Bool")
print(boolValue)

//NSURL类型
//设置
userDefault.setURL(NSURL(string: "http://www.iphonetrain.com")!, forKey: "NSURL")
//读取
let urlValue = userDefault.URLForKey("NSURL")
print(urlValue)

//保存NSDate数据
//将对象转换成NSData流
let imageData:NSData = NSKeyedArchiver.archivedDataWithRootObject(UIImage(named: "SwiftClassWeiXin.png")!)

//存储NSData对象
userDefault.setObject(imageData, forKey: "imageData")

//读取数据
//获取NSData
let objData:AnyObject? = userDefault.objectForKey("imageData")

//还原对象-初始一个UIImage对象
let myImage:AnyObject? = NSKeyedUnarchiver.unarchiveObjectWithData(objData as! NSData)

print(myImage)

//自定义的类实现存取需要通过NSData做载体

//创建AppsModel的实例
let model = AppsModel(imageName: "appIcon2.png", app_Name: "租房点评", app_Description: "租房被骗？现在开始，你来改变这一切！《租房点评》为你而备，租房无忧！")

//实例对象转换成NSData
let modelData:NSData = NSKeyedArchiver.archivedDataWithRootObject(model)

//存储NSData对象
userDefault.setObject(modelData, forKey: "myAppModel")

//保存NSString,
userDefault.setValue("1_NSString", forKey: "NSString")
userDefault.setObject("1_NSString1", forKey: "NSString1")

//保存NSNumber,
let number:NSNumber = NSNumber(int: 32)
userDefault.setValue(number, forKey: "number")
userDefault.setObject(number, forKey: "number1")

//保存NSArray
let array1:NSArray = NSArray(array:["22222","33333"])
userDefault.setValue(array1, forKey: "array")
userDefault.setObject(array1, forKey: "array1")

//保存NSDictionary
let dictionary:NSDictionary = NSDictionary(dictionary: ["1":"1111"])
userDefault.setValue(dictionary, forKey: "dictionary")
userDefault.setObject(dictionary, forKey: "dictionary1")

var value:AnyObject? = userDefault.valueForKey("dictionary")
print(value)

value = userDefault.objectForKey("dictionary1")
print(value)

//-------- 删除所有的值
let ar:NSDictionary = userDefault.dictionaryRepresentation()

for key in ar.allKeys {

userDefault.removeObjectForKey(key as! String)

userDefault.synchronize()//内存中数据同步更新数据库
}

2、文件操作

应用开发中所有的非代码文件都存储在沙盒中。

//1、获取程序的Home目录
let homeDirectory = NSHomeDirectory()
print(homeDirectory)

//2、获取Documents目录
let documentPaths = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true)

let documentPath = documentPaths[0]
print(documentPath)

//或通过home目录自己追加文件夹
let documentPath2 = homeDirectory + "/Documents"
print(documentPath2)

//3、获取Library目录
let libraryPaths = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.LibraryDirectory, NSSearchPathDomainMask.UserDomainMask, true)
let libraryPath = libraryPaths[0]
print(libraryPath)

//或通过home目录自己追加文件夹
let libraryPath2 = homeDirectory + "/Library"
print(libraryPath2)

//4、获取Cache目录
let cachesPaths = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.CachesDirectory, NSSearchPathDomainMask.UserDomainMask, true)
let cachesPath = cachesPaths[0]
print(cachesPath)

//或通过home目录自己追加文件夹
let cachesPath2 = homeDirectory + "/Library/Caches"
print(cachesPath2)

//5、获取Tmp目录
let tmpDir = NSTemporaryDirectory()
print(tmpDir)

//或通过home目录自己追加文件夹
let tmpDir2 = homeDirectory + "/tmp"
print(tmpDir2)

对文件操作需要先创建一个文件管理器

// 创建文件管理器
let fileManager :NSFileManager = NSFileManager.defaultManager()

//创建目录
//定义几个自己的目录
let myDirectory1:String = NSHomeDirectory() + "/Documents/myFolder/Images"
let myDirectory2:String = NSHomeDirectory() + "/Documents/myFolder/Films"
let myDirectory3:String = NSHomeDirectory() + "/Documents/myFolder/Musics"
let myDirectory4:String = NSHomeDirectory() + "/Documents/myFolder/Files"

//创建目录
//withIntermediateDirectories 设置成true，代表中间所有的路径目录如果不存在，都会创建
//如果设置成false，因为myFolder目录不存在，所以无法创建1234目录

//创建myDirectory1目录
do
{
try fileManager.createDirectoryAtPath(myDirectory1, withIntermediateDirectories: true, attributes: nil)
}
catch let error as NSError {
print(error)//如果创建失败，error 会返回错误信息
}

//创建myDirectory2目录
do
{
try fileManager.createDirectoryAtPath(myDirectory2, withIntermediateDirectories: true, attributes: nil)
}
catch let error as NSError {
print(error)//如果创建失败，error 会返回错误信息
}

//创建myDirectory3目录
do
{
try fileManager.createDirectoryAtPath(myDirectory3, withIntermediateDirectories: true, attributes: nil)
}
catch let error as NSError {
print(error)//如果创建失败，error 会返回错误信息
}

//创建myDirectory4目录
do
{
try fileManager.createDirectoryAtPath(myDirectory4, withIntermediateDirectories: true, attributes: nil)
}
catch let error as NSError {
print(error)//如果创建失败，error 会返回错误信息
}

Swift 的错误处理机制要求你必须使用 do-catch 语句来捕获所有的错误并处理他们。

//创建文件
let filePath = myDirectory1 + "/appInfo.txt"
let info = "经常听到：被中介骗了，押金不退，晚一天交房租，被讹了。租房普遍现象：网上报价不真实？经常被忽悠！（看房时报价都比网上高！）证件不齐全，被骗过!（其实根本不是房东啦!）看房前态度都很热情！ 签约之后态度骤变!入住后家电维修只能靠自己！ 房屋到期，押金各种被勒索！现在开始，你来改变这一切！《租房点评》为你而备，租房无忧！再也不用担心被欺骗，想要知道给你介绍房子的人好不好，《租房点评》告诉你！"

通过writeToFile方法，将一些对象写入到文件中

do
{
try info.writeToFile(filePath, atomically: true, encoding: NSUTF8StringEncoding)
}
catch let error as NSError {
print(error)//如果创建失败，error 会返回错误信息
}

//保存图片
let image = UIImage(named: "SwiftClassWeiXin@3x.png")
let data:NSData = UIImageJPEGRepresentation(image!, 1.0)!
let data1:NSData = UIImagePNGRepresentation(image!)!
data.writeToFile(myDirectory1 + "/SwiftClassIcon.jpg", atomically: true)
data1.writeToFile(myDirectory1 + "/SwiftClassIcon.png", atomically: true)

//保存NSArray
let array = NSArray(objects: "111","222","333")
array.writeToFile(myDirectory4 + "/array.plist", atomically: true)

//保存NSDic
let dictionary = NSDictionary(objects: ["1111","22222","33333"], forKeys: ["1","2","3"])
dictionary.writeToFile(myDirectory4 + "/dictionary.plist", atomically: true)

//判断目录或文件是否存在
let exist = fileManager.fileExistsAtPath(filePath)
print(exist)

//移动
let filePath2 = myDirectory4 + "/appInfo.txt"
do
{
try fileManager.moveItemAtPath(filePath, toPath: filePath2)
}
catch let error as NSError {
print(error)//如果创建失败，error 会返回错误信息
}

//重命名
//通过移动该文件对文件重命名
let filePath3 = myDirectory4 + "/appInfo2.txt"
do
{
try fileManager.moveItemAtPath(filePath2, toPath: filePath3)
}
catch let error as NSError {
print(error)//如果创建失败，error 会返回错误信息
}

//拷贝
let filePath4 = myDirectory4 + "/appInfoCopy.txt"
do
{
try fileManager.copyItemAtPath(filePath3, toPath: filePath4)
}
catch let error as NSError {
print(error)//如果创建失败，error 会返回错误信息
}

//获取目录列里所有文件名
//先拷贝一些文件到myDirectory4目录下
let filePath00 = myDirectory4 + "/appInfoCopy00.txt"
let filePath11 = myDirectory4 + "/appInfoCopy11.txt"
let filePath22 = myDirectory4 + "/appInfoCopy22.txt"
do
{
try fileManager.copyItemAtPath(filePath3, toPath: filePath00)
try fileManager.copyItemAtPath(filePath3, toPath: filePath11)
try fileManager.copyItemAtPath(filePath3, toPath: filePath22)
}
catch let error as NSError {
print(error)//如果创建失败，error 会返回错误信息
}

//获取所有文件
let fileArray = fileManager.subpathsAtPath(myDirectory4)
print(fileArray)
//        Optional([appInfo.txt, appInfo2.txt, appInfoCopy.txt, appInfoCopy00.txt, appInfoCopy11.txt, appInfoCopy22.txt])

//iPhone中获取文件各项属性方法
//获取文件属性
do
{
var fileAttributes : [NSObject:AnyObject]? = try NSFileManager.defaultManager().attributesOfItemAtPath(filePath22)

//获取文件的创建日期
let modificationDate:AnyObject? = fileAttributes![NSFileModificationDate]
print(modificationDate)

//获取文件的字节大小
let fileSize:AnyObject? = fileAttributes![NSFileSize]
print(fileSize)
}
catch let error as NSError {
print(error)//如果创建失败，error 会返回错误信息
}

//删除文件
do
{
try fileManager.removeItemAtPath(filePath4)
}
catch let error as NSError {
print(error)//如果创建失败，error 会返回错误信息
}

//删除目录下所有文件
//方法1： 获取所有文件，然后遍历删除
let fileArray2 : [AnyObject]? = fileManager.subpathsAtPath(myDirectory4)
for fn in fileArray2!
{
do
{
try fileManager.removeItemAtPath(myDirectory4 + "/\(fn)")
}
catch let error as NSError {
print(error)//如果创建失败，error 会返回错误信息
}
}

//方法2：删除目录后重新创建该目录
do
{
try fileManager.removeItemAtPath(myDirectory4)
try fileManager.createDirectoryAtPath(myDirectory4, withIntermediateDirectories: true, attributes: nil)
}
catch let error as NSError {
print(error)//如果创建失败，error 会返回错误信息
}
}