Swift-归档和解档

项目中遇到需要存储的数据目前有四种方式，偏好设置(UserDefaults)，文件存储，SQLite，CoreData，第一种方式比较简单，第二种方式一般使用归档和解档的方式实现，先来简单了解一下App基本目录:

FlyElephant.png

偏好设置

偏好设置比较简单，设置数据取数据，代码如下:

let defaults:UserDefaults = UserDefaults.standard
        defaults.setValue("FlyElephant", forKeyPath: "userName")

设置的数据最终保存在Plist文件中:

FlyElephant.png

归档和解档

自定义对象存储需要实现NSCoding协议中的encode和decode方法:

public protocol NSCoding {

    
    public func encode(with aCoder: NSCoder)

    public init?(coder aDecoder: NSCoder) // NS_DESIGNATED_INITIALIZER
}

自定义归档的Order对象:

class Order:NSObject,NSCoding {
    
    var orderName:String = ""
    
    var userName:String = ""
    
    init(orderName:String, userName:String) {
        self.orderName = orderName
        self.userName = userName
        super.init()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init()
        self.orderName = aDecoder.decodeObject(forKey: "OrderName") as! String
        self.userName = aDecoder.decodeObject(forKey: "UserName") as! String
    }
    
    func encode(with aCoder: NSCoder) {
        
        aCoder.encode(self.orderName, forKey:"OrderName")
        
        aCoder.encode(self.userName, forKey: "UserName")
    }
    
}

归档操作:

@IBAction func archiverAction(_ sender: UIButton) {
        
        let order:Order = Order(orderName: "123456789", userName: "FlyElephant")
        
        NSKeyedArchiver.archiveRootObject(order, toFile: getSavePath())
    }

解档操作:

@IBAction func unArchiverAction(_ sender: UIButton) {
        
        let order:Order = NSKeyedUnarchiver.unarchiveObject(withFile: getSavePath()) as! Order
        
        print("订单的名称:\(order.orderName)---用户名称--\(order.userName)")
        
    }

存储路径:

private func getSavePath()->String {
        let cacheDir:String = NSSearchPathForDirectoriesInDomains(.cachesDirectory, .userDomainMask, true)[0]
        let localPath:String = cacheDir.appending("TempTest.plist")
        return localPath;
    }

保存数据:

FlyElephant.png