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

1 //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 2 let userDefault:NSUserDefaults = NSUserDefaults.standardUserDefaults() 3 4 //通过init方法创建 5 let userDefault1:NSUserDefaults = NSUserDefaults(suiteName: "SwiftClass")! 6 print(userDefault1.dictionaryRepresentation()) 7 8 //获取userDefault单利下所有的值 9 print(userDefault.dictionaryRepresentation()) 10 11 //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。 12 if(userDefault.objectForKey("message") == nil){ 13 userDefault.setObject("This_is_my_default_message", forKey: "message") 14 } 15 16 //如果想单独看某个key的设置，例如: 17 let dic = userDefault.dictionaryRepresentation() 18 let object_one:AnyObject? = (dic as NSDictionary).objectForKey("AppleKeyboards") 19 // //或者 20 // var object_one:AnyObject? = dic["AppleKeyboards"] 21 22 if let oValue: AnyObject! = object_one { 23 print(oValue) 24 } 25 26 27 //Int类型 28 //设置 29 userDefault.setInteger(123456, forKey: "Int") 30 //读取 31 let intValue = userDefault.integerForKey("Int") 32 print(intValue) 33 34 //Float类型 35 //设置 36 userDefault.setFloat(3.2, forKey: "Float") 37 //读取 38 let floatValue = userDefault.floatForKey("Float") 39 print(floatValue) 40 41 //Double类 42 //设置 43 userDefault.setDouble(5.6890, forKey: "Double") 44 //读取 45 let doubleValue = userDefault.doubleForKey("Double") 46 print(doubleValue) 47 48 //Bool类型 49 //设置 50 userDefault.setBool(true, forKey: "Bool") 51 //读取 52 let boolValue = userDefault.boolForKey("Bool") 53 print(boolValue) 54 55 //NSURL类型 56 //设置 57 userDefault.setURL(NSURL(string: "http://www.iphonetrain.com")!, forKey: "NSURL") 58 //读取 59 let urlValue = userDefault.URLForKey("NSURL") 60 print(urlValue) 1 //保存NSDate数据 2 //将对象转换成NSData流 3 let imageData:NSData = NSKeyedArchiver.archivedDataWithRootObject(UIImage(named: "SwiftClassWeiXin.png")!) 4 5 //存储NSData对象 6 userDefault.setObject(imageData, forKey: "imageData") 7 8 //读取数据 9 //获取NSData 10 let objData:AnyObject? = userDefault.objectForKey("imageData") 11 12 //还原对象-初始一个UIImage对象 13 let myImage:AnyObject? = NSKeyedUnarchiver.unarchiveObjectWithData(objData as! NSData) 14 15 print(myImage) 1 //自定义的类实现存取需要通过NSData做载体 2 3 //创建AppsModel的实例 4 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！") 5 6 //实例对象转换成NSData 7 let modelData:NSData = NSKeyedArchiver.archivedDataWithRootObject(model) 8 9 //存储NSData对象 10 userDefault.setObject(modelData, forKey: "myAppModel") 1 //保存NSString, 2 userDefault.setValue("1_NSString", forKey: "NSString") 3 userDefault.setObject("1_NSString1", forKey: "NSString1") 4 5 //保存NSNumber, 6 let number:NSNumber = NSNumber(int: 32) 7 userDefault.setValue(number, forKey: "number") 8 userDefault.setObject(number, forKey: "number1") 9 10 //保存NSArray 11 let array1:NSArray = NSArray(array:["22222","33333"]) 12 userDefault.setValue(array1, forKey: "array") 13 userDefault.setObject(array1, forKey: "array1") 14 15 //保存NSDictionary 16 let dictionary:NSDictionary = NSDictionary(dictionary: ["1":"1111"]) 17 userDefault.setValue(dictionary, forKey: "dictionary") 18 userDefault.setObject(dictionary, forKey: "dictionary1") 1 var value:AnyObject? = userDefault.valueForKey("dictionary") 2 print(value) 3 4 value = userDefault.objectForKey("dictionary1") 5 print(value) 6 7 8 9 //-------- 删除所有的值 10 let ar:NSDictionary = userDefault.dictionaryRepresentation() 11 12 for key in ar.allKeys { 13 14 userDefault.removeObjectForKey(key as! String) 15 16 userDefault.synchronize()//内存中数据同步更新数据库 17 }

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 //1、获取程序的Home目录 2 let homeDirectory = NSHomeDirectory() 3 print(homeDirectory) 4 5 6 //2、获取Documents目录 7 let documentPaths = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true) 8 9 let documentPath = documentPaths[0] 10 print(documentPath) 11 12 //或通过home目录自己追加文件夹 13 let documentPath2 = homeDirectory + "/Documents" 14 print(documentPath2) 15 16 //3、获取Library目录 17 let libraryPaths = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.LibraryDirectory, NSSearchPathDomainMask.UserDomainMask, true) 18 let libraryPath = libraryPaths[0] 19 print(libraryPath) 20 21 //或通过home目录自己追加文件夹 22 let libraryPath2 = homeDirectory + "/Library" 23 print(libraryPath2) 24 25 26 27 28 //4、获取Cache目录 29 let cachesPaths = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.CachesDirectory, NSSearchPathDomainMask.UserDomainMask, true) 30 let cachesPath = cachesPaths[0] 31 print(cachesPath) 32 33 //或通过home目录自己追加文件夹 34 let cachesPath2 = homeDirectory + "/Library/Caches" 35 print(cachesPath2) 36 37 38 //5、获取Tmp目录 39 let tmpDir = NSTemporaryDirectory() 40 print(tmpDir) 41 42 //或通过home目录自己追加文件夹 43 let tmpDir2 = homeDirectory + "/tmp" 44 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() 1 //创建目录 2 //定义几个自己的目录 3 let myDirectory1:String = NSHomeDirectory() + "/Documents/myFolder/Images" 4 let myDirectory2:String = NSHomeDirectory() + "/Documents/myFolder/Films" 5 let myDirectory3:String = NSHomeDirectory() + "/Documents/myFolder/Musics" 6 let myDirectory4:String = NSHomeDirectory() + "/Documents/myFolder/Files" 7 8 //创建目录 9 //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 10 //如果设置成false，因为myFolder目录不存在，所以无法创建1234目录 11 12 //创建myDirectory1目录 13 do 14 { 15 try fileManager.createDirectoryAtPath(myDirectory1, withIntermediateDirectories: true, attributes: nil) 16 } 17 catch let error as NSError { 18 print(error)//如果创建失败，error 会返回错误信息 19 } 20 21 //创建myDirectory2目录 22 do 23 { 24 try fileManager.createDirectoryAtPath(myDirectory2, withIntermediateDirectories: true, attributes: nil) 25 } 26 catch let error as NSError { 27 print(error)//如果创建失败，error 会返回错误信息 28 } 29 30 //创建myDirectory3目录 31 do 32 { 33 try fileManager.createDirectoryAtPath(myDirectory3, withIntermediateDirectories: true, attributes: nil) 34 } 35 catch let error as NSError { 36 print(error)//如果创建失败，error 会返回错误信息 37 } 38 39 //创建myDirectory4目录 40 do 41 { 42 try fileManager.createDirectoryAtPath(myDirectory4, withIntermediateDirectories: true, attributes: nil) 43 } 44 catch let error as NSError { 45 print(error)//如果创建失败，error 会返回错误信息 46 }

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

 

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