Swift使用NSCoding编码元组

Question

是否可以使用NSCoding？存储元组？我有一个像元组一样的元组((UInt8, UInt8), (UInt8, UInt8)).但是aCoder.encodeObject(myTuple)不起作用.我是否必须将元组转换为NSData或者这绝对不可能？谢谢你的帮助

Answer 1

元组不能被编码,因为它不是一个类,但一种方法是分别编码元组的每个组件,然后在解码时解码每个组件,然后将元组的值设置为由解码内容构造的元组.

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

        let obj = SomeClass()
        obj.foo = (6,5)

        let data = NSKeyedArchiver.archivedDataWithRootObject(obj)
        NSUserDefaults.standardUserDefaults().setObject(data, forKey: "books")

        if let data = NSUserDefaults.standardUserDefaults().objectForKey("books") as? NSData {
            let o = NSKeyedUnarchiver.unarchiveObjectWithData(data) as SomeClass
            println(o.foo) // (Optional(6), Optional(5))

        }
    }
}

class SomeClass: NSObject, NSCoding {
    var foo: (x: Int?, y: Int?)!

    required convenience init(coder decoder: NSCoder) {
        self.init()
        let x = decoder.decodeObjectForKey("myTupleX") as Int?
        let y = decoder.decodeObjectForKey("myTupleY") as Int?
        foo = (x,y)
    }

    func encodeWithCoder(coder: NSCoder) {
        coder.encodeObject(foo.x, forKey: "myTupleX")
        coder.encodeObject(foo.y, forKey: "myTupleY")
    }
}