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UserDefaults适合轻量级的本地客户端存储，存储一个值，新值可以覆盖旧值，可以重复存储，也可以存储一次，然后直接从UserDefaults里面读取上次存储的信息，很方便，用的时候，宏定义下，直接调用！ 轻量级数据库的话，移动端一般使用SQlite数据库，也是一款轻量级的适合移动端设备的数据库，具体可以参考我以前写的关于SQlite的博客，当然了UserDefaults根本不用管这些东西，直接就想读取字符串一样，直接读取就可以了！ UserDefaults支持的数据格式也很多：有：Int，Float，Double，BOOL，Array，Dictionary，甚至 Any 类型 1. 样例展示：
func get_uuid() -> String { let userID = UserDefaults.standard.string(forKey: "HHGGLL") //判断UserDefaults中是否已经存在 if userID != nil { return userID! }else{ let uuid_ref = CFUUIDCreate(nil) let uuid_string_ref = CFUUIDCreateString(nil, uuid_ref) let uuid = uuid_string_ref! as String UserDefaults.standard.set(uuid, forKey: "HHGGLL") return uuid } }
输出： print("用户的UUID：\(get_uuid())") 如上图！ 2.其他基本数据类型和any类型的存储 //存储练习 let userDefault = UserDefaults.standard //any userDefault.set("hgl001", forKey: "object") let objectValue:Any? = userDefault.object(forKey: "object") print("\(objectValue as! String)") //int userDefault.set(12345, forKey: "int") let intValue = userDefault.integer(forKey: "int") print(intValue) //float userDefault.set(3.2, forKey: "float") let floatValue = userDefault.float(forKey: "float") print(floatValue) //double userDefault.set(5.2369, forKey: "double") let doubleValue = userDefault.double(forKey: "double") print(doubleValue) //bool userDefault.set(true, forKey: "bool") let boolValue = userDefault.bool(forKey: "bool") print(boolValue) //url userDefault.set(URL(string:"http://hangge.com")!, forKey: "URL") let urlValue = userDefault.url(forKey: "URL") print(urlValue) //string类型 userDefault.set("hgl is a hero!", forKey: "string") let stringValue = userDefault.string(forKey: "string") print(stringValue) //nsnumber类型 var number = NSNumber(value:22) userDefault.set(number, forKey: "number") number = userDefault.object(forKey: "number") as! NSNumber print(number) //array类型 var array:Array = ["123","223"] userDefault.set(array, forKey: "Array") array = userDefault.array(forKey: "Array") as! [String] print(array) //Dictionary类型 var dictory = ["name":"hero11223"] userDefault.set(dictory, forKey: "dictory") dictory = userDefault.dictionary(forKey: "dictory") as! [String:String] print(dictory) //系统对象的存储与读取 let userDeafaults = UserDefaults.standard //存储对象 let label = UILabel() label.text = "天空飘来五个字" let labelData = NSKeyedArchiver.archivedData(withRootObject: label) //存储data对象 userDefault.set(labelData, forKey: "labelData") //对象读取 //获取data let objData = userDefault.data(forKey: "labelData") //还原对象 let mylabel = NSKeyedUnarchiver.unarchiveObject(with: objData!) as? UILabel print(mylabel) //UIImage对象存储 let image1 = UIImage(named:"1.jpeg") let image2 = UIImage(cgImage: (image1?.cgImage!)!, scale: (image1?.scale)!, orientation: (image1?.imageOrientation)!) let imageData = NSKeyedArchiver.archivedData(withRootObject: image2) //存储Data对象 userDefault.set(imageData, forKey: "imageData") //UIImage对象读取 //获取Data let objDatas = userDefault.data(forKey: "imageData") //还原对象 let myImg = NSKeyedUnarchiver.unarchiveObject(with: objDatas!) print("输出是\(myImg)") 打印如下图： 3.删除存储对象 通过removeObject()方法可以删除已保存的数据 UserDefaults.standard.removeObject(forKey: "key值")
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