swift - 如何实现 NSCoding

Question

import Foundation

class C: NSObject, NSCoding {
    var n: String = ""

    override init() {
        super.init()
        n = "instance of class C"
    }

    convenience init(_ name: String) {
        self.init()
        n = name
    }

    required init(coder: NSCoder) {
        // self.init()
        // super.init()
        // super.init(coder)
        n = coder.decodeObjectForKey("name") as String
    }

    func encodeWithCoder(coder: NSCoder) {
        coder.encodeObject(n, forKey:"name")
    }

    override var description: String {
        get { return "C instance: \(n)" }
    }
}

let c = C("Tom")
println(c)
if NSKeyedArchiver.archiveRootObject(c, toFile: "demo") {
    println("OK")
}
let c2: C = NSKeyedUnarchiver.unarchiveObjectWithFile("demo") as C

在命令行上编译

xcrun swift coder.swift

调用NSKeyedUnarchiver.unarchiveObjectWithFile失败，崩溃

> xcrun swift coder.swift
C instance: Tom
OK
2014-09-06 10:45:11.925 swift[483:100b] *** Terminating app due to uncaught exception
'NSInvalidUnarchiveOperationException', reason: '*** -[NSKeyedUnarchiver decodeObjectForKey:]: cannot decode object of class (coder.C)'

我看过各种“工作示例”，但它们似乎不适合我。所有注释行都不起作用或没有帮助。我做错了什么？

Answer 1

我建议打开雷达(bugreport.apple.com)。如果您编译它而不是尝试通过 swift 解释器直接运行它，则效果很好。它可以在 Xcode 中运行。它适用于 Playground 。它与 xcrun -sdk macosx swiftc coder.swift && ./coder 配合使用。唯一不起作用的情况是通过 swift。